Cognitive Loss/Impaired Sensory Gating from HCN Channels - Recovered by PDE4 Inhibition or an α2A Receptor Agonist

Today we have a complex dysfunction, but we have a plausible understanding of the detailed biological underpinnings and several therapeutic options. It is relevant to people with autism who have impaired sensory gating (they find noises like a clock ticking annoying), and perhaps those who struggle with complex thought. It is very likely to be disturbed in some people with ADHD and many with schizophrenia.

Trouble in the Pre-Frontal Cortex

For a recap on sensory gating, here is an earlier post:-

Sensory Gating in Autism, Particularly Asperger's

Today’s dysfunction relates to HCN channels located on those tiny dendritic spines in a part of the brain called the pre-frontal cortex. These are a type of voltage gated potassium channel found in your brain and heart, there are 4 types, it looks to me that HCN2 is the key one today.

The pre-frontal cortex (PFC) is seen as the part of the brain most affected by mental illness (schizophrenia, bipolar, ADHD etc.), although medicine’s current understanding looks rather medieval to me.

These HCN channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network (created by numerous interacting neurons) is effectively disconnected.

By keeping these channels closed, it is thought that you can improve working memory and reducing distractibility. Now you might think distractibility is an odd word, and it is not a word I expected to encounter, what it really means is impaired sensory gating. This is a core feature of Asperger’s, ADHD and schizophrenia.

One of the key risk genes for schizophrenia, DISC1, also affects HCN channels and this may account for some of the cognitive deficit found in schizophrenia. High level thinking is particularly affected.  It is thought that loss of DISC1 function in the PFC would likely prevent proper PDE4 function, leading to a dysregulated build-up of cAMP in dendritic spines resulting in excessive opening of HCN channels

Role of disrupted in schizophrenia 1 (DISC1) in stress-induced prefrontal cognitive dysfunction

I did wonder how nicotine fits in, since in earlier post we saw that α7 nAChR agonists, like nicotine, improve sensory gating and indeed that people with schizophrenia tend to be smokers. It turns out that nicotine is also an HCN channel blocker. For a change, everything seems to fit nicely together. There are different ways to block HCN channels, some of which are indirect. One common ADHD drug, Guanfacine, keeps these channels closed, but in a surprising way.

Alpha-2A adrenergic receptors near the HCN channels, on those dendritic spines, inhibit the production of cAMP and the HCN channels stay closed, allowing the information to pass through into the cell, connecting the network. These Alpha-2A adrenergic  receptors are stimulated by a natural brain chemical norepinephrine, or by drugs like Guanfacine.

Stress appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

This would explain why stress makes people’s sensory gating problems get worse. So someone with Asperger’s would get more distracted/disturbed at exam time at school for example, or when he goes for a job interview. Reducing stress is another method to improve sensory gating and indeed cognition. In Monty, aged 14 with ASD, the only time he exhibits significantly impaired sensory gating, is when he has stopped all his Polypill therapies for several days. I think stress/anxiety is what has changed and this opens those HCN channels. Then even the sound of someone eating food next to him makes him angry.

Excessive opening of HCN channels might underlie many lapses in higher cognitive function.

While the researchers at Yale patented the idea of HCN blockers to improve cognition, we can see how other existing ideas to improve cognition may indeed have the same mechanism, most notably PDE4 inhibitors.

The University of Maastricht holds patents on the use of Roflumilast, a PDE4 inhibitor, to improve cognition; most interestingly, this takes effect at one fifth of the COPD dosage, for which it is an approved drug. At high doses PDE4 inhibitors have annoying side effects, but at low doses they tend to be trouble-free.

One effect of a PDE4 inhibitor is that it reduces cAMP. So a PDE4 inhibitor acts indirectly like an HCN blocker.

Not surprisingly recent research showed that low doses of Roflumilast improves sensory gating in those affected by this issue.

So rather than waiting for a brain selective HCN blocker, the potential exists to use a one fifth dose of Roflumilast today. This is something that should indeed be investigated across different types of cognitive dysfunction.

There are numerous dysfunctions that can impair cognition and they can occur in different diagnosis. For example impaired autophagy is a key feature of Huntington’s, impaired remyelination defines multiple sclerosis, low levels of nerve growth factor are a key feature of Rett syndrome. Less severe dysfunctions of these processes occur in entirely different conditions.

It is thought that people with Alzheimer’s might benefit from PDE4 inhibition. If it was me, I would try it in all types of dementia or cognitive loss of any kind.

PDE4 Inhibitors

There have been many mentions of PDE4 inhibitors elsewhere in this blog. They are broadly anti-inflammatory and anti-oxidant, but currently only widely used to treat asthma in Japan and COPD in Western countries. COPD is a kind of very severe asthma.

Traditionally a PDE4 inhibitor is thought of as drug used to block the degradative action of phosphodiesterase 4 (PDE4) on cyclic adenosine monophosphate (cAMP). That all sound complicated, just think of it as increasing cAMP.

Now cAMP is a messenger in many biological processes, one of which relates to PKA (Protein Kinase A). In autism we know that PKA, PKB and PKC are often disturbed. These PKs are very important because they have the ability to literally change the function of thousands of proteins in your body. This is similar to how epigenetic tags can switch on or switch off a particular gene. PKs, via a different mechanism we will look at in another post, change the function of proteins, so it is very important that you have the correct level of PKA, PKB and PKC.

We saw in a recent post that the Pitt Hopkins gene TCF4 is regulated by PKA and that under-expression of TCF4 is also a feature of some ID and schizophrenia. So more PKA, please.

The Intellectual Disability and Schizophrenia Associated Transcription Factor TCF4 Is Regulated by Neuronal Activity and Protein Kinase A 

You can use a PDE4 inhibitor to increase cAMP, which then increases PKA.

Other effects of PDE4 inhibitors

Today’s post is about sensory gating and the effect here of PDE4 inhibitors is via the effect of cAMP on those HCN channels in your tiny dendritic spines.

There are numerous other effects of PDE4 that may also be therapeutic. One interesting effect is that inhibition of PDE4 can mimic calorie restriction by activating AMPK/SIRT1 pathway.

Calorie restriction has just been shown in a large trial to be able to reverse type 2 diabetes, if initiated with a few years of the disease developing.

Humans have evolved based to periods of feast and famine. Periods of fasting may be therapeutic for many modern conditions.

Not surprisingly one side effect of PDE4 inhibitors is weight loss. Many psychiatric drugs cause troubling weight gain.

Acute administration of Roflumilast enhances sensory gating in healthy young humans in a randomized trial. 

Abstract

 

INTRODUCTION:

Sensory gating is a process involved in early information processing which prevents overstimulation of higher cortical areas by filtering sensory information. Research has shown that the process of sensory gating is disrupted in patients suffering from clinical disorders including attention deficit hyper activity disorder, schizophrenia, and Alzheimer's disease. Phosphodiesterase (PDE) inhibitors have received an increased interest as a tool to improve cognitive performance in both animals and man, including sensory gating.

METHODS:

The current study investigated the effects of the PDE4 inhibitor Roflumilast in a sensory gating paradigm in 20 healthy young human volunteers (age range 18-30 years). We applied a placebo-controlled randomized cross-over design and tested three doses (100, 300, 1000 μg).

RESULTS:

Results show that Roflumilast improves sensory gating in healthy young human volunteers only at the 100-μg dose. The effective dose of 100 μg is five times lower than the clinically approved dose for the treatment of acute exacerbations in chronic obstructive pulmonary disease (COPD). No side-effects, such as nausea and emesis, were observed at this dose. This means Roflumilast shows a beneficial effect on gating at a dose that had no adverse effects reported following single-dose administration in the present study.

CONCLUSION:

The PDE4 inhibitor Roflumilast has a favourable side-effect profile at a cognitively effective dose and could be considered as a treatment in disorders affected by disrupted sensory gating.

Treating Cognitive Impairment with Roflumilast, Maastricht University

Background Information

Selective phosphodiesterase (PDE) inhibition has been considered as a very promising target for cognition enhancement.

Roflumilast is a PDE4 inhibitor that has been developed by Takeda for Chronic Obstructive Pulmonary Disease (COPD). In recent year, Maastricht University has been collaborating with Takeda to develop Roflumilast for cognitive impairments

In 2015 Takeda sold COPD indication of Roflumilast to AstraZeneca, and ownership of IP for treatment of cognitive impairment returned to Maastricht University.

Compelling clinical results

A single administration of Roflumilast improves episodic memory in mice, and in young and elderly healthy subjects at a non-emetic dose

As shown in the figure, healthy (A) and memory impaired (B) elderly subjects showed better performances in the delayed recall of the Verbal Learning Task after roflumilast

Key Features and Advantages

Opportunities to reposition a clinically-proven safe compound with a well-established pharmacology.

Compelling preclinical and clinical evidences showing that Roflumilast effectively deliver to the brain to produce robust cognitive enhancement.

Pro-cognitive effects at low dose (5 times lower than COPD indication), which allows to circumvent the emetic effects commonly observed with other PDE4 inhibitors

Maastricht University has a strong IP protection extending to at least 2033.

Effect of Roflumilast on cognitive function in schizophrenia

PDE inhibitors in psychiatry--future options for dementia, depression and schizophrenia?

Author information

Abstract

Phosphodiesterases are key enzymes in cellular signalling pathways. They degrade cyclic nucleotides and their inhibition via specific inhibitors offers unique 'receptor-independent' opportunities to modify cellular function. An increasing number of in vitro and animal model studies point to innovative treatment options in neurology and psychiatry. This review critiques a selection of recent studies and developments with a focus on dementia/neuroprotection, depression and schizophrenia. Despite increased interest among the clinical neurosciences, there are still no approved PDE inhibitors for clinical use in neurology or psychiatry. Adverse effects are a major impediment for clinical approval. It is therefore necessary to search for more specific inhibitors at the level of different PDE sub-families and isoforms.

Brain Networks Strengthened By Closing Ion Channels, Research Could Lead To ADHD Treatment

The current study found that brain cells in PFC contain ion channels called hyperpolarization-activated cyclic nucleotide-gated channels (HCN) that reside on dendritic spines, the tiny protrusions on neurons that are specialized for receiving information. These channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network is effectively disconnected. Arnsten said inhibiting cAMP closes the channels and allows the network to reconnect.

Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility," she said. "This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels."

Arnsten said the excessive opening of HCN channels might underlie many lapses in higher cognitive function. Stress, for example, appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

The study also found alpha-2A adrenergic receptors near the channels that inhibit the production of cAMP and allow the information to pass through into the cell, connecting the network. These receptors are stimulated by a natural brain chemical  norepinephrine or by medications like guanfacine.

 “Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility,” she said. “This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels.”

Yale has submitted a patent application on the use of HCN blockers for the treatment of PFC cognitive deficits based on the data reported in the Cell paper.

The full Yale paper:

α2A-Adrenoceptors Strengthen Working Memory Networks by Inhibiting cAMP-HCN Channel Signaling in Prefrontal Cortex

Guanfacine for the Treatment of Cognitive Disorders: A Century of Discoveries at Yale

The prefrontal cortex (PFC) is among the most evolved brain regions, contributing to our highest order cognitive abilities. It regulates behavior, thought, and emotion using working memory. Many cognitive disorders involve impairments of the PFC. A century of discoveries at Yale Medical School has revealed the neurobiology of PFC cognitive functions, as well as the molecular needs of these circuits. This work has led to the identification of therapeutic targets to treat cognitive disorders. Recent research has found that the noradrenergic α2A agonist guanfacine can improve PFC function by strengthening PFC network connections via inhibition of cAMP-potassium channel signaling in postsynaptic spines. Guanfacine is now being used to treat a variety of PFC cognitive disorders, including Tourette’s Syndrome and Attention Deficit Hyperactivity Disorder (ADHD). This article reviews the history of Yale discoveries on the neurobiology of PFC working memory function and the identification of guanfacine for treating cognitive disorders.

Nicotine blocks the hyperpolarization-activated current Ih and severely impairs the oscillatory behavior of oriens-lacunosum moleculare interneurons.

Molecular modeling suggests that, similarly to ZD 7288, nicotine and epibatidine directly bind to the inner pore of the HCN channels. It is therefore likely that nicotine severely influences rhythmogenesis and high cognitive functions in smokers.

Modulation of HCN channels in lateral septum by nicotine

Conclusion

I think many people stand to benefit from the drugs mentioned in today’s post, but for different biological reasons. A person with Pitt Hopkins may benefit from Roflumilast because it will upregulate PKA and then increase expression of their remaining TCF4 gene.

In a person with schizophrenia there are multiple reasons these drugs might help them and it will depend on which genes they have that are misexpressed (TCF4, DISC1 etc.).

In a person with idiopathic Asperger’s and impaired sensory gating it looks like the effect on HCN channels is what is important.

I think low dose Roflumilast has great potential for many. The Japanese drug Ibudilast very likely will provide similar benefits, but at what dosage?

PDE4 inhibitors do have side effects at higher doses in part because there are several different types of PDE4 (PDE4A, PDE4B, PDE4C etc) and different drugs effect different subtypes differently.

Ibudilast is used as a daily drug therapy for asthma in Japan and is being studied as a therapy for Multiple Sclerosis (MS) in the US.

Roflumilast is sold by Astra Zeneca as Daxas/Daliresp but at a high dose of 500mcg to treat flare ups of COPD (Chronic Obstructive Pulmonary Disease) it does cause troubling side effects, but it reduces your chance of dying from COPD.

The cognitive dose used in research is 100mcg. Higher doses had no cognitive/sensory gating benefit.

Further investigation of the ADHD drug Guanfacine should be made, because some of the people who benefit from a PDE4 inhibitor might get a similar effect from Guanfacine. People with Pitt Hopkins would not be in this category. A person with Asperger’s and impaired sensory dating should respond to Guanfacine, a cheap drug.

At the end of the day, choice of therapy will come down to side effects and cost. In the US, Roflumilast is expensive ($330), seven times more expensive than in some other countries; in the UK the price of the same 30 tablets is $50. One pack would be enough for 5 months at the suggested dose.

Under-expression (Haploinsufficiency) of ARID1B in Autism and Corpus Callosum Abnormalities

People keep telling me that my blog is too complicated; compared to the literature it really is not. If your child has a disabling condition you really should be willing to invest all the time needed to learn about it, rather than be a passive bystander.

I think you can investigate even complex sounding genetic disorders without being an expert, which is what happens in today’s post.  

Are there 20,000 types of jeans?

As readers may recall, humans only have about 20,000 genes, far less than originally was thought. Each gene provides the instructions to make one thing, usually a protein.

For the great majority of genes we have two copies, one from Mum and one from Dad. Mitochondrial genes all come from Mum.

These genes are stored on chromosomes (like recipe books).

For 22 of these recipe books you have two copies, so if one page got damaged at least you have an undamaged version from the other book.

The 23rd pair of books is special because while females have two copies, males do not. This is the X chromosome and if a male has a problem on any page in this little book, he has a big problem, while his sister has less of a problem, because she has a spare copy. The male has a Y chromosome in place of a second copy of X. 

Examples of problems on the X chromosome:-

·        The MECP2 gene is on the X chromosome and when there is one working copy and one mutated version you have Rett syndrome and you must be female. If you were male with one mutated version you cannot survive.

·        In Fragile X syndrome a problem with the FMR1 gene means not enough not enough fragile X mental retardation protein (FMRP), which is required for normal development of the connection between neurons. Females would normally have a clean spare copy of the FMR1 gene and so show much less severe symptoms that a male with Fragile X.

Problems on chromosomes 1 to 22:-

If you have a problem in the first 22 chromosomes (recipe books), boys and girls are equal. If one page got damaged you can always look up the recipe in the other book.

In case one gene got mutated but the other copy is fine, things can work out just fine, in which case it is called haplosufficiency. You get to make enough of that protein.

In some cases you really need to use that recipe a lot; that particular protein is in big demand. One copy of that gene just is not enough. This is called  haploinsufficiency.

In most cases when the gene has a problem, it just fails to produce the intended protein. In some cases it actually produces a mutated protein, which can be worse than no protein. 

Pitt Hopkins

In Pitt Hopkins Syndrome there is a problem on chromosome 18, where you find the TCF4 gene. Not enough expression of TCF4 means not enough Transcription Factor 4;  this is an example of haploinsufficiency.

Now the reason why these rare conditions are important to many other people is that they not only affect people who happened to have a random mutation and hence a severe deficit of the protein; moderately reduced transcription of this gene, for any reason, can also result in troubling symptoms.

So in the case of the Pitt Hopkins and the gene TCF4, as was pointed out to me recently, reduced expression is a feature of some MR/ID and indeed schizophrenia. 

The Intellectual Disability and Schizophrenia Associated Transcription Factor TCF4 Is Regulated by Neuronal Activity and Protein Kinase A 

Instead of just a tiny number of people with Pitt Hopkins, you can see that upregulating TCF4 expression could help a lot of people.

It appears that people with Pitt Hopkins have a “clean copy” of TCF4, so it is just a case of making it work a little harder. There are ways being researched to achieve just that.

I suspect people with schizophrenia have two “clean copies” of TCF4, but for some reason have a deficiency of the protein encoded by it.

In the above paper it was shown that Protein Kinase A (PKA) plays a key role in regulating what your TCF4 gene is producing.

We have come across PKA before in this blog and we know that in regressive autism there can be a deficit of PKA. There is also PKB and PKC. All three are very important, but complicated. 

Brain Region–Specific Decrease in the Activity and Expression of Protein Kinase A in the Frontal Cortex of Regressive Autism

Without going into all the details you can see that if someone with Pitt Hopkins has a lack of PKA, like those with regressive autism, then he will struggle to make the most of his good copy of the gene TCF4.

It all gets very complicated, but PKA is controlled by something called cAMP. In turn cAMP is controlled by PDE. PDE4 is known to be disturbed in the brains of some people with autism.

It appears that you can activate PKA with a PDE4 inhibitor. The long established Japanese asthma drug Ibudilast is such a PDE4 inhibitor. At least one reader of this blog uses Ibudilast long term.

PDE4 inhibitor, roflumilast protects cardiomyocytes against NO-induced apoptosis via activation of PKA and Epac dual pathways

PDE4 inhibitors have been explored to treat various neurological conditions like schizophrenia.

PDE4 as a target for cognition enhancement

So logically if you feed a PDE4 inhibitor to a Pitt Hopkins mouse, you might expect something good to happen. There now is such a mouse model.

I think I could keep that mouse quite busy. 

The point being you do not have to figure things out 100%, before starting to see what you have in your drug library might be truly beneficial.  

Some of the things in the drug library are actually in the kitchen cupboard, as we have already seen. 

Protein Kinase A

Protein kinase A (PKA) is something that is both complicated and important.

The effects of PKA activation vary with cell type.

PKA has always been considered important in formation of a memory.  Formation of a normal memory is highly sensitive to PKA levels; too much is bad and too little is bad.

ARID1B in Autism and Corpus Callosum Abnormalities

I don’t think anyone has set up a research foundation for agenesis of the Corpus Callosum (ACC), perhaps they should. 

There was a post on this a while back, prompted by meeting someone whose son has this condition. 

Agenesis of the Corpus Callosum

The Corpus Callosum is just a fancy name for what joins the two sides of the brain together. Agenesis of the Corpus Callosum (ACC) is what they call it when there is a complete or partial absence of the corpus callosum.

ACC is we are told a very rare condition, but clearly smaller corpus callosum variations are a key part of some autism. 

For example, in Pitt Hopkins a small corpus callosum is typical.

An estimated 7 percent of children with autism and macrocephaly (big heads) carry a PTEN mutation. This is associated with an enlarged corpus callosum. 

PTEN is an autism gene, but it is more usually thought of as a tumor suppressor, making it a cancer gene. In older people, losing PTEN appears to be often a first step to developing cancer; up to 70% of men with prostate cancer are estimated to have lost a copy of the PTEN gene at the time of diagnosis  (https://www.ncbi.nlm.nih.gov/pubmed/16079851). 

PTEN is interesting because too little can allow cancer to develop, but too much may eventually result in type 2 diabetes. So, as always, it is a balance. 

PTEN upregulation may explain the development of insulin resistance and type 2 diabetes with high dose statins. 

Evidently from the comments in this blog, regarding tumors/cancers, people with autism are likely shifted towards the direction of lacking tumor suppressing proteins. The exception would be those born very small, or with small heads. 

ARID1B gene

ARID1B is another tumor suppressing gene, like PTEN, and like PTEN it is also an autism gene.

What I found interesting was the link between ARID1B and corpus callosum anomalies. 

ARID1B mutations are the major genetic cause of corpus callosum anomalies in patients with intellectual disability  

Corpus callosum abnormalities, intellectual disability, speech impairment, and autism inpatients with haploinsufficiency of ARID1B

Corpus callosum abnormalities are common brain malformations with a wide clinical spectrum ranging from severe intellectual disability to normal cognitive function. The etiology is expected to be genetic in as much as 30–50% of the cases, but the underlying genetic cause remains unknown in the majority of cases.

Additional functional studies including a systematic search for ARID1B target genes may show how haploinsufficiency of ARID1B predispose to CC defects and to an array of cognitive defects, including severe speech defects

Several readers of this blog have highlighted a recent study:-  

Breakthrough research suggests potential treatment for autism, intellectual disability 

We showed that cognitive and social deficits induced by an Arid1b mutation in mice are reversed by pharmacological treatment with a GABA receptor modulating drug. And, now we have a designer mouse that can be used for future studies." 

The full study:-

Arid1b haploinsufficiency disrupts cortical interneuron development and mouse behavior

Clonazepam also reversed the reduced time spent in the center and reduced moving distance displayed by Arid1b-mutant mice in the open field test (Fig. 7c,d and Supplementary Fig. 14c). However, depression measures, using the forced swim test and the tail suspension test, showed no reversible effect of clonazepam in Arid1b+/− mice compared with controls (Fig. 7e,f). Our results show that clonazepam rescues impaired recognition, social memory, and elevated anxiety in Arid1b+/− mice. 

Our mouse model effectively mirrors the behavioral characteristics of intellectual disability and ASD. Arid1b+/− and Arid1bconditional-knockout mice displayed impaired spatial learning, recognition memory, and reference memory. Open field and social behavior tests also revealed decreased social interaction in the mice. Mice with mutations in genes encoding Smarca2 and Actl6b, other subunits of the BAF complex, have severe defects in social interaction and long-term memory35. Thus, this chromatin remodeling complex may provide a cellular and molecular platform for normal intellectual and social behavior. In addition, Arid1b+/− mice showed heightened levels of anxiety- and depression-related behaviors, which are common symptoms of ASD36. 

For people with intellectual disability, the prevalence of anxiety disorders has likewise been shown to be much higher. This may be due to reduced cognitive function and increased vulnerability to environmental demands. Communication difficulties may also make it more difficult for people with cognitive disabilities to deal with anxiety or fear. ARID1B haploinsufficiency may be responsible for multiple facets of characteristic ASD behaviors. Other isoforms of Arid1b that are not affected by the Arid1b mutation could exist in the mouse line. Additionally, it is possible that the genetic background for the mouse line may impact the effect of Arid1b haploinsufficiency. Thus it is important to consider allele specificity, genetic backgrounds, and knockout strategies for comparing phenotypes of other Arid1bhaploinsufficiency models.  

GABA allosteric modulators, including clonazepam, a benzodiazepine, have been used to treat seizures and anxiety. We found that clonazepam injection rescued deficits in object and social recognition and anxiety in Arid1b+/− mice. These results suggest that treatment with a benzodiazepine could be a potential pharmacological intervention for symptoms of ASD. Furthermore, our results suggest that pharmacological manipulation of GABA signaling is a potential treatment strategy for cognitive and social dysfunctions in ASD- or intellectual disability-associated disorders due to mutations in chromatin remodeling genes.  

ACC Research Foundation

If there actually was an ACC Research Foundation, they could explore whether clonazepam was therapeutic in children who have Arid1b haploinsufficiency.

While they are at it, they might want to look into Hereditary Motor and Sensory Neuropathy with agenesis of the corpus callosum (HMSN/ACC), this is caused by mutations in the potassium-chloride co-transporter 3 (SLC12A6/KCC3) gene. This I stumbled upon a long time ago, when trying to upregulate KCC2, which causes elevated intracellular chloride in many people with autism and likely many with Down Syndrome.

KCC2 is usually associated with neuropathic pain and now we see that so is KCC3. Odd reaction to pain is a well known feature of autism. The rather ill-defined condition of fibromyalgia seems common in female relatives of those with autism and I do not think this is just a coincidence. 

The interesting thing is that the research shows you can potentially upregulate KCC3 with curcumin. 

Transit Defect of Potassium-Chloride Co-transporter 3 Is a Major Pathogenic Mechanism in Hereditary Motor and Sensory Neuropathy with Agenesis of the Corpus Callosum

HMSN/ACC is a severe and progressive neurodegenerative disease that exhibits an early onset of symptoms. Signs of HMSN/ACC, such as hypotonia and delays in motor development skills, are noticed before 1 year of age. However, the motor abilities of patients progress slowly to 4–6 years of age, and these children are able to stand and walk with some help. This is followed by a motor deterioration that generally renders affected subjects wheelchair-dependent by adolescence. 

Accordingly, we found that curcumin relieved the ER retention of dimerized R207C in mammalian cultured cells. A diet enriched in curcumin may therefore be beneficial for the relief or delay of some of the HMSN/ACC symptoms in patients bearing the R207C mutation, including the Turkish patient described in this study (as patient has not yet reached puberty).

KCC3 defects also cause the very similar Andermann syndrome also known as agenesis of corpus callosum with neuronopathy (ACCPN).

KCC3 defects are associated with epilepsy.

My question was can you have KCC3 under-expression with partial ACC, epilepsy but no peripheral neuropathy? If this was likely, then upregulating KCC3 with curcumin might help.

The gene for KCC3 is located at chromosome 15q14. Based on my “logic of associations”, if you have ACC and epilepsy you should consider KCC3 under-expression.

I did suggest to my former classmate whose son has partial ACC and epilepsy, but no neuropathy, that it might be worth trying some curcumin. Since his son is already on anti-epileptic drugs (AEDs) my suggested effect to look for was improved cognitive function.

6 months later it does indeed, apparently, improve cognitive function.  Of course this does not establish that upregulating KCC3 had anything to do with it. It is nonetheless a nice story and another parent has realized that you can change things for the better, in spite of what neurology currently says. 

The question now is can you have both ARID1B under-expression and KCC3 under-expression, in which case you would add some clonazepam, based on the latest research. At this point you should of course go and talk to your neurologist, rather than read my blog and that was my recommendation. 

Partial agenesis of the corpus callosum in a patient with juvenile myoclonic epilepsy

We describe a patient who presented at our epilepsy-monitoring unit with myoclonic jerks, and was diagnosed with juvenile myoclonic epilepsy (JME). Imaging of his brain revealed partial agenesis of the corpus callosum (ACC). We discuss the known genetic basis of both JME and ACC, as well as the role of the corpus callosum (CC) in primary generalized epilepsy. Both JME and ACC are associated with gene loci on chromosome 15q14. Structural brain abnormalities other than ACC, such as atrophy of the corpus callosum have been reported in patients with JME. ACC has been associated with seizures, suggesting an anti-epileptogenic role of the corpus callosum

Conclusion

If you have a biological diagnosis you are one big step closer to finding a therapy. Even if you have a diagnosis like partial Agenesis of the Corpus Callosum (ACC), you can go one step further and ask why. You have a 50% chance of being able to find out a specific gene that is the cause. If you know with certainty which gene is the originator of the problem, you know a lot.  I think you are then two big steps closer to a therapy.

In the case of Rett Syndrome, a really good website is run by their research foundation (Rett Syndrome Research Trust). They look like they mean business. 

https://reverserett.org/cure/

If you look at the above site you might be left wondering why the much larger and better financed autism organizations look so amateur by comparison.  The big difference is that Rett Syndrome is a biological diagnosis and autism is not. In many ways calling autism a spectrum is not helpful, as the originators of the ASD concept are beginning to realize.  The precise biological dysfunctions are what matter and lumping together hundreds of miscellaneous brain dysfunctions into a pile labelled ASD may not be so clever, in fact I would call it primitive.

Histamine Reaction to Bio Gaia Gastrus

Alli from Switzerland discovered the autism benefits of Bio Gaia Gastrus.

This probiotic contains two different bacteria:-

·        Lactobacillus reuteri 17938 (Lactobacillus reuteri Protectis)

 ·        Lactobacillus reuteri ATCC PTA 6475

These two bacteria have different effects.

The first bacteria is very well researched and recently was shown to increase oxytocin in autism mouse studies.  It is available on its own and this is the product most people I know are using.

The second bacteria is included in Bio Gaia Gastrus specifically for its additional anti-inflammatory effects.

Recent comments on this blog have shown that some people have a negative “histamine-y" reaction to Bio Gaia Gastrus.  This is entirely logical since the mode of action of the second bacteria is to generate histamine to activate H2 receptors in the gut.

This might sound rather odd since histamine is thought of as inflammatory, but the researchers working for Bio Gaia have shown that histamine can produce the opposite effect, suppressing TNF via Modulation of PKA and ERK Signaling.

Histamine Derived from Probiotic Lactobacillus reuteri Suppresses TNF via Modulation of PKA and ERK Signaling

Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s) produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC) separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA), histidine/histamine antiporter (hdcP), and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2)-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H₂receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA) and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases.

This may mean that people who respond well to H2 histamine antagonists (Zantac, Tagamet etc) are unlikely to benefit from Lactobacillus. reuteri ATCC PTA 6475.

It might also mean that people who respond negatively to Bio Gaia Gastrus might get benefit from H2 histamine antagonists.

It might be worthwhile people trialing the single bacteria Bio Gaia product (Protectis), if they have a negative reaction to Gastrus.

Therapeutic Epigenetics in Autism and Junk DNA

Epigenopathies were introduced in an earlier post

Today’s post takes another dip into the genetics of autism and currently existing therapies that could be re-purposed for autism.  We also see that many secrets remain beyond the 3% of your DNA that usually gets all the research attention.  The remaining 97% is not junk after all.

There was an earlier post on this blog that introduced Epigenetics.  It is not such a complicated subject, just think about it as little tags on your DNA that turn genes on/off usually when they should not be, but there remains the possibility to use epigenetics for good.  In people with under-expression of an important gene you could “tag it” and then increase its expression.

The exome is the part of your DNA that encodes the various proteins needed to build your body.  The remaining 97% of your DNA was once thought to be just junk; we saw in recent post that one part contains enhancers and silencers that control expression of the genes in the 3% that is the exome.

A recent study of gene expression in neurological conditions including autism showed just how broadly disturbed gene expression is.

Post-mortem transcriptomes from patients with Alzheimer'sdisease, Autism and Schizophrenia show distinctive cellular phenotypes.

(A) Consistent fold enrichments were found for each cell type across fourteen cortical and three subcortical brain regions of Alzheimer's patients. The box plots mark the distribution of cellular fold enrichments across all the brain regions examined. Asterisks mark that the fold enrichment for each cell type that was found to be significantly non-zero with p < 0.05. (B) Two independent autism studies show the same cellular phenotypes, including upregulation of glial cells and downregulation of neurons. Asterisks mark those cell types found to be significantly differential with p < 0.05 after BH correction over all groups.

Here I am making the point that even though only a handful of genes may have an identifiable dysfunction, a much broader range of genes seem to be affected, as we see in the wide range of over and under expressed genes.

While it would be logical to think about a specific dysfunction needing a therapy that targets just that gene, this appears not to be necessary.

It appears that downstream processes may be the most damaging/relevant, for example disturbances in Protein Kinase A and C (PKA and PKC) may play a key role in many cases of regressive autism, and this will feature in its own post, because it would be treatable today. 

Reduced activity of protein kinase C in the frontal cortex of subjects with regressive autism: relationship with developmental abnormalities.

Brain Region–Specific Decrease in the Activity and Expression of Protein Kinase A inthe Frontal Cortex of Regressive Autism

 

Both the above papers are by Abha and Ved Chauhan.  I put Abha on my Dean’s list long ago.  I did have a discussion with her a while back.  She is clearly a very nice person and intellectually towers over the Curemark lady (Joan Fallon) who gets $40 million to play with her pancreatic enzymes, but never publishes anything except very superficial patents.

I think for $40 million Abha and Ved could figure it all out.

PKB, otherwise known as Akt is also very relevant to some types of autism.

Tamoxifen, recently shown to reverse autism in a SHANK3 mouse model, is a PKC inhibitor.

Another epigenetic drug, Theophylline activates PKA.

Akt, also known as protein kinase B (PKB), is a central node in cell signaling downstream of growth factors, cytokines, and other cellular stimuli. Aberrant loss or gain of Akt activation underlies the pathophysiological properties of a variety of complex diseases, including type-2 diabetes and cancer.

If you could identify if a particular person was hypo/hyper in PKA, PKB and PKC, this might well open the door to an effective treatment.

Research on PKB, also known as AKT

Dysregulation of theIGF-I/PI3K/AKT/mTOR signaling pathway in autism spectrum disorders.

Decreased Phosphorylated Protein Kinase B (Akt) inIndividuals with Autism Associated with High Epidermal Growth Factor Receptor(EGFR) and Low Gamma-Aminobutyric Acid (GABA)

And a paper from the clever Japanese:-

Roles of PTEN/PI3K/AKT/GSK3β Pathway in Neuron Signaling Involved in Autism

Autism spectrum disorder is a set of neurodevelopmental disorders in terms of prevalence, morbidity and impact to the society, which is characterized by intricate behavioral phenotype and deficits in both social and cognitive functions. The molecular pathogenesis of autism spectrum disorder has not been well understood, however, it seems that PI3K, AKT, and its downstream molecules have crucial roles in the molecular pathogenesis of autism spectrum disorder. The PI3K/AKT signaling pathway plays an important role in the regulation of cell proliferation, differentiation, motility, and protein synthesis. Deregulated PI3K/AKT signaling has also been shown to be associated with the autism spectrum disorder. Discovery of molecular biochemical phenotypes would represent a breakthrough in autism research. This study has provided new insight on the mechanism of the disorder and would open up future opportunity for contributions to understand the pathophysiology

For those who favour dietary intervention:-

  
Based on the above chart curcumin should likely be good for my N=1 case of autism. Time will tell.

Consequences of upstream dysfunctions

So it might be better to consider autism as a disease of wider downstream gene expression, rather than necessarily of “faulty” genes.  Modulating the resulting wider gene expression may be much more realistic than fixing individual genes.

It is certainly plausible that the body has its own protective self-repair mechanism that might be somehow re-energized. Some people have pondered why so many highly intelligent mathematicians and computer scientists seem have relatives with autism.  The clever genes do associate with a type of autism plus ID/MR.  It was suggested that protective genetic changes might be in play, so that the people with the most genetic variance are actually the family members without the autism.

This does remain conjecture, but as more whole genome data is collected we are seeing some interesting findings.

A fascinating very recent study that looked at a group of 53 families with autism using the traditional approach of whole exome sequencing and also microarray. 

Using these methods, that are the current gold standard, the researchers found very little.  Dysfunctions in the 700 known autism genes were not detected.

However using more expensive whole genome sequencing, dysfunctions were identified in the “DNA junk” zone very close beside the known autism genes.  The researchers were then able to identify the genetic cause of 30% of the cases, a big improvement on 0%.  I expect if they looked a little harder the 30% would be higher.

“We performed whole-genome sequencing (WGS) of 208 genomes from 53 families affected by simplex autism.”

“For the majority of these families, no copy-number variant (CNV) or candidate de novo gene-disruptive single-nucleotide variant (SNV) had been detected by microarray or whole-exome sequencing (WES).

Comparing the sequences of the individuals with autism and those of their unaffected siblings, the researchers found that people with autism are more likely to have genetic variants — either single base-pair changes in the sequence or small CNVs — in swaths of DNA abutting known autism genes. But the researchers only found the variants after they restricted their search to regions of the genome already implicated in autism, and even then the statistical significance is modest.

Sequencing whole genomes could reveal the genetic cause of autism in as much as 30 percent of people for whom faster and cheaper sequencing methods come up short

“It’s increasing power even in areas that are supposed to be covered by whole-exome sequencing,” says Peixoto. “It seems that it’s clear that whole-genome sequencing will become the standard.”

Spaces near genes may harbor pitfalls for autism

Genome Sequencing of Autism-Affected Families Reveals Disruption of Putative Noncoding Regulatory DNA.

One specific microRNA has strong links to autism spectrum disorder, say TSRI scientists

Epigenopathies

Many diseases have an epigenetic component. The severe progressive asthma that is COPD is a well-known example.  It appears that smoking in middle age often leads to permanent epigenetic changes that come back to haunt often then non-smokers in old age.  Even though they have not smoked for twenty years, there oxidative stress response has been permanently modified.  This results in a kind of steroid resistance, so that usually reliable drug therapies fail to work. 

It is thought that autism has an epigenetic component.  This would do some way to explaining 30-40% of the increase in prevalence in recent years that is not explained by ever widening diagnostic criteria.

Because epigenetic changes can be heritable and can be accumulated from all kinds of exposures, even simple ones like severe emotional stress and pollution, you can reconcile autism as being primarily a genetic condition even though incidence has clearly risen within one or two generations. So you can have an “epigenetic epidemic”, so to speak.

Epigenetics as a therapy

While much is written about epigenetic change being bad, it could also be good.

There are many known substances that affect gene expression; some are very target specific which is useful.

This answers a recent issue raised by a reader of this blog who did exome sequencing. What is the point of discovering a genetic dysfunction if there is no therapy? Medicine is some decades behind science, better to know what gene is affected because you well be able to affect its expression, you just need some help from Google.

Epigenetic therapy could be used to remove unwanted tags, but it could also be used to leave new ones to upregulate under-expressed genes.

Such epigenetic therapy is already a reality in COPD and is being considered for rare single autisms where one copy of the gene is not functional, so turn up the volume on the remaining copy.

As we saw in the post on epigenetics, one potential category of drugs are HDAC inhibitors, these would affect one epigenetic mechanism.

There are many such HDAC inhibitors and most have other modes of action, so you cannot be sure what is giving the noted effect.

Valproate

This epilepsy drug has numerous effects including as a HDAC inhibitor.  Given to mothers during pregnancy it can cause autism in the offspring, but when given to the affected offspring the autism can be reduced.

Valproate is given off label to treat autism even when no epilepsy is present.

As we saw in the comments section, long term valproate se can have side effects.

Sulforaphane

This substance derived from broccoli and patented by Johns Hopkins, is another HDAC inhibitor.  It also upregulates Nrf2, which turns on the oxidative response genes.  This was proposed as a COPD therapy by Professor Barnes.

We saw in a post that for Nrf2 to have its full effect there needed to be enough of a protein called DJ-1.  You can increase DJ-1 expression with cinnamon (sodium benzoate).

That was one reason to think that cinnamon would complement Sulforaphane as a therapy for both COPD and some autism.

Sodium Butyrate

Sodium Butyrate is an HDAC inhibitor that is available as a supplement. We came across it in an earlier post as a precursor to butyric acid.  Butyric acid plays a role in the permeability of the gut and the Blood Brain Barrier (BBB).  It also seems to protect from auto immune disease.

Butyrate is fed to millions of farm animals every day to increase their resistance to auto-immune disease.

Butyric acid is produced naturally in the gut by the bacteria living there, however the amount can be increased by the uses of a particular probiotic-bacteria.

This would support the uses of sodium butyrate and the Miyari 588 bacteria.

I have on my to-do-list to investigate higher doses of Miyari 588, but having read the comment by Alli that 500 mg of sodium butyrate is effective, I will try that first.  She also found higher doses ineffective, which was the same in a mouse study published last November,

The study below highlights which genes were down-regulated and which were up-regulated, the overall effect was beneficial

Sodium butyrate attenuate ssocial behavior deficits and modifies the transcription ofinhibitory/excitatory genes in the frontal cortex of an autism model.

 

The core behavioral symptoms of Autism Spectrum Disorders (ASD) include dysregulation of social communication and the presence of repetitive behaviors. However, there is no pharmacological agent that is currently used to target these core symptoms. Epigenetic dysregulation has been implicated in the etiology of ASD, and may present a pharmacological target. The effect of sodium butyrate, a histone deacetylase inhibitor, on social behavior and repetitive behavior, and the frontal cortex transcriptome, was examined in the BTBR autism mouse model. A 100 mg/kg dose, but not a 1200 mg/kg dose, of sodium butyrate attenuated social deficits in the BTBR mouse model. In addition, both doses decreased marble burying, an indication of repetitive behavior, but had no significant effect on self-grooming. Using RNA-seq, we determined that the 100 mg/kg dose of sodium butyrate induced changes in many behavior-related genes in the prefrontal cortex, and particularly affected genes involved in neuronal excitation or inhibition. The decrease in several excitatory neurotransmitter and neuronal activation marker genes, including cFos Grin2b, and Adra1, together with the increase in inhibitory neurotransmitter genes Drd2 and Gabrg1, suggests that sodium butyrate promotes the transcription of inhibitory pathway transcripts. Finally, DMCM, a GABA reverse agonist, decreased social behaviors in sodium butyrate treated BTBR mice, suggesting that sodium butyrate increases social behaviors through modulation of the excitatory/inhibitory balance. Therefore, transcriptional modulation by sodium butyrate may have beneficial effects on autism related behaviors.

  

Theophylline

Theophylline is an old asthma drug that is an HDAC inhibitor.

At low doses it is now being trialled as an epigenetic add-on therapy in COPD.  It pretty obviously does work, but data needs to be collected to measure how effective it is and what is the best dose.

It shows how the COPD researchers/clinicians like Professor Barnes are doing a good job and not frightened to experiment.

Would a similar low dose of theophylline benefit a sub-group of those with autism/schizophrenia?  I think it is quite likely.

COPD and autism/schizophrenia share the same impaired oxidative stress response.

A randomised, double-blind placebo controlled trial of the effectiveness of low dose oral theophylline as an adjunct to inhaled corticosteroids in preventing exacerbations of chronic obstructive pulmonary disease (TWICS)

Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease characterised by progressive airflow limitation. In the UK, it affects around 3 million people, is the fifth leading cause of death and costs the NHS approximately £1 billion annually. Exacerbations of COPD account for 60% of NHS COPD costs and are associated with accelerated rate of lung function decline, reduced physical activity, reduced quality of life, increased mortality and increased risk of co-morbidities. COPD treatment guidelines recommend inhaled corticosteroids (ICS) to reduce exacerbations and improve lung function. However, in COPD, airway inflammation is relatively insensitive to the anti-inflammatory effects of ICS and even high doses fail to prevent exacerbations. Preclinical and pilot studies demonstrate that low dose theophylline may increase the sensitivity of the airway inflammation to ICS, and thus when used with ICS will reduce the rate of COPD exacerbation. In this study we will determine the clinical effectiveness and cost-effectiveness of adding low dose theophylline to ICS therapy in patients with COPD. The primary outcome is the number of exacerbations. The primary economic outcome is the cost-per-QALY gained during the one year treatment period. We will recruit 1424 participants from primary and secondary care across seven areas of the UK. Participants will be randomised to theophylline (200 mg once or twice daily depending on smoking status and weight) or placebo for 12 months. We will follow participants up at six and twelve months to assess the number of exacerbations. We will also collect data on adverse events, health care utilisation, quality of life and breathlessness, and lung function. Low dose theophylline is cheap (10p/day) and, if shown to make current ICS therapy more effective in a cost effective manner, it will improve the quality of life of COPD patients and reduce the burden of COPD on the NHS.

At large doses, Theophylline has long been a therapy for asthma and COPD, but as with Sodium Butyrate, it is quite possible that larger doses of Theophylline produce a different result.  In other words the epigenetic effect fortunately comes from the low dose.

Low doses mean less chance of side effects.

For example, in anyone predisposed to reflux/GERD/GORD many asthma drugs pose a problem because at the same time as opening the airways in your lungs they will relax the lower esophageal sphincter and allow stomach acid to rise upwards.

We saw in an earlier post that in some types of autism something called mGluR5 is dysfunctional in the brain. By chance mGluR5 is also involved in closing the lower esophageal sphincter.  In people with reflux/GERD/GORD a mGluR5 inhibitor was found to have promise for the management of their symptoms.

Randomised clinical trial:effects of monotherapy with ADX10059, a mGluR5 inhibitor, on symptoms and reflux events in patients with gastro-oesophageal reflux disease.

So it is not surprising that many people with autism also have reflux/GERD/GORD. 

But the dysfunction with mGluR5 in autism can be both hyper and hypo, so the therapy might be a positive allosteric modulator (PAM), or a negative allosteric modulator (NAM).  

In someone with autism + reflux/GERD/GORD  it would be reasonable to think a NAM, like ADX10059, might help both conditions.

Gene Repression and Genome Stability

There is another epigenetic process that may be disturbing gene expression in some people and may be treatable.

I have been trying to find why so many people with autism can benefit from biotin; I think I have found a plausible explanation.

“Biotinylation of histones plays a role in gene repression and repression of transposable elements, thereby maintaining genome stability”

I think in some people with autism and no clinical deficiency of biotin the continued “overdosing” of biotin might be having an effect on gene expression, bringing things a little closer to where they should be.

Rather beyond the scope of this blog, it appears that in some people the impaired genome stability, reversible with biotin(ylation), this might be a significant cancer risk.

In essence, for most people supraphysiological concentrations of biotin will do absolutely nothing, but in a sub-group it might do a lot of good.  It is epigenetic, but you do not have to understand it to benefit from it.  It is complicated.

Biotinylation of Histones Represses Transposable Elements in Human and Mouse Cells and Cell Lines and in Drosophila melanogaster

Transposable elements such as long terminal repeats (LTR) constitute ∼45% of the human genome; transposition events impair genome stability. Fifty-four promoter-active retrotransposons have been identified in humans. Epigenetic mechanisms are important for transcriptional repression of retrotransposons, preventing transposition events, and abnormal regulation of genes. Here, we demonstrate that the covalent binding of the vitamin biotin to lysine-12 in histone H4 (H4K12bio) and lysine-9 in histone H2A (H2AK9bio), mediated by holocarboxylase synthetase (HCS), is an epigenetic mechanism to repress retrotransposon transcription in human and mouse cell lines and in primary cells from a human supplementation study. Abundance of H4K12bio and H2AK9bio at intact retrotransposons and a solitary LTR depended on biotin supply and HCS activity and was inversely linked with the abundance of LTR transcripts. Knockdown of HCS in Drosophila melanogaster enhances retrotransposition in the germline. Importantly, we demonstrated that depletion of H4K12bio and H2AK9bio in biotin-deficient cells correlates with increased production of viral particles and transposition events and ultimately decreases chromosomal stability. Collectively, this study reveals a novel diet-dependent epigenetic mechanism that could affect cancer risk.

Here, we provide evidence for the existence of a novel diet-dependent epigenetic mechanism that represses retrotransposons. Importantly, we demonstrated that depletion of biotinylated histones in biotin-deficient cells increases LTR transcript levels, production of viral particles, and retrotransposition events, and ultimately decreases chromosomal stability. Both biotin deficiency and supplementation are prevalent in the US. For example, moderate biotin deficiency has been observed in up to 50% of pregnant women (35,36). About 20% of the US population reports taking biotin supplements (37), producing supraphysiological concentrations of vitamin in tissues and body fluids (23,28,35). The findings presented here suggest that altered biotin status in these population subgroups might affect chromosomal stability and cancer risk. 

Biotin and biotinidase deficiency

Biotin requirements for DNA damage prevention

  

Conclusion

I never got round to writing part 2 of my epigenetics post, but my experience of HDAC inhibitors to date has been very positive.

I would be the first to admit that this is rather hit and miss.  It was only when reading the paper on potential therapies for Pitt Hopkins, that was openly musing about HDAC inhibitors, in an equally hit and miss approach, that I thought I would write further about it.

It really seems totally haphazard, because you cannot predict the effect with any level of certainty.  If there is a self-repair mechanism trying to maintain homeostasis of the genome, haphazard may be good enough.

10mg of biotin twice a day does have a mild but noticeable stabilizing effect; is this caused by better maintaining genome stability? I have no idea. 

I will try sodium butyrate and if it works I will have to establish what dose of Miyari 588 produces the same effect.  Both are used in animal feed to reduce inflammatory disease, so you are already indirectly exposed to them if you eat meat.

Theophylline should also be investigated.  This is a very well understood drug and small doses really do seem to help people with COPD.

PKA, PKB and PKC are likely at the core of most people’s autism.  Many existing therapies can modify their expression.

Whole genome sequencing, carried out at great precision, is clearly the only satisfactory genetic testing method.  The other, cheaper, methods are just missing key data and giving many false negative results, i.e. saying there are no identifiable genetic dysfunctions, when this is not true.