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Monday 13 January 2014

Epigenetics and Autism


I have touched on the subject of epigenetics in a previous post; it is a new area of science that shows how the environment can modify your genes.  Rather than you being purely a product of your parents’ genes, you actually also have both your own environmentally acquired epigenetic changes, and some of the acquired epigenetic changes of your ancestors.

These acquired epigenetic changes are caused by things like emotional trauma, chemical insults and even smoking.
Epigenetic control systems generally involve three types of proteins: “writers”, “readers”, and “erasers.” Writers attach chemical marks, such as methyl groups (to DNA) or acetyl groups (to the histone proteins that DNA wraps around). So-called “readers” bind to these marks, thereby influencing gene expression; erasers remove the marks.

 

In theory epigenetic changes should be reversible, but this is not simple.
You may recall in an earlier post about asthma, we learnt that it is very hard to treat former smokers.  Once a person has smoked heavily, a change occurs whereby the body remains in permanent oxidative stress and conventional asthma drugs are not very effective.  The fact that the person gave up smoking 20 years previously does not help.  The only way to treat the patient is to first treat them with an antioxidant and NAC was the most effective; even then the result is not so good.


Epigenetics and Autism
It is said that autism is caused by a combination of genetic and environmental factors; but it might be better stated that autism is caused by genetic and epigenetic factors.  Those epigenetic factors would include all the accumulated environmental factors affecting that person and his ancestors.

As modern life becomes more distant from the village life of our ancestors, you can imagine a gradual build-up of environmental and stress factors.  If you cannot erase some of those marks, you will reach a point where the “tainted” DNA will produce aberrations.  Such aberrations might trigger cancer in one person and autism in another. 

Epigenetic Drugs
Cancer was identified very early as being a likely consequence of epigenetic changes.  Cancer research is very well funded and some epigenetic drugs are already available.  The idea is that epigenetic drugs should selectively target reversible epigenetic changes

A particular problem is that the drug has to act very selectively.
If you were able to erase all those chemical marks on someone’s DNA, there would most likely be some unwanted and unanticipated changes.

One pioneer in this field is a US firm called Acetyton Pharmaceuticals.
 

Epigenetic Research in Autism
The good news is that research has recently started in this area, and it might eventually lead to the possibility of reversing some of those unwanted epigenetic changes.

Here is rather heavy study from Kings College in London:-

 
Autism spectrum disorder (ASD) defines a group of common, complex neurodevelopmental disorders. Although the aetiology of ASD has a strong genetic component, there is considerable monozygotic (MZ) twin discordance indicating a role for non-genetic factors. Because MZ twins share an identical DNA sequence, disease-discordant MZ twin pairs provide an ideal model for examining the contribution of environmentally driven epigenetic factors in disease. We performed a genome-wide analysis of DNA methylation in a sample of 50 MZ twin pairs (100 individuals) sampled from a representative population cohort that included twins discordant and concordant for ASD, ASD-associated traits and no autistic phenotype. Within-twin and between-group analyses identified numerous differentially methylated regions associated with ASD. In addition, we report significant correlations between DNA methylation and quantitatively measured autistic trait scores across our sample cohort. This study represents the first systematic epigenomic analyses of MZ twins discordant for ASD and implicates a role for altered DNA methylation in autism.

 

For those of you who prefer some milk in your coffee, those helpful people at the MIND Institute in Sacramento have produced a series of video lectures on this very subject.
Here is the full list:


 and here is one particular video.


  
Conclusion
Epigenetics would help explain the increasing prevalence of ASD in the most developed countries.  It also opens the door to potentially highly effective treatment mechanisms to many currently incurable conditions.

Perhaps, by chance, one of the new epigenetic drugs developed for cancer will have a positive effect in ASD.

 
 

 

Sunday 5 January 2014

Long Term Bumetanide Use in Autism


This blog started life after I read about a clinical trial of the diuretic bumetanide to treat autism.  In the following 12 months the authors of that study, Ben-Ari and Lemmonier, have been busy building up their scientific case.  They published two further papers:-
 
 
We report that daily administration of the diuretic NKCC1 chloride co-transporter, bumetanide, reduces the severity of autism in a 10-year-old Fragile X boy using CARS, ADOS, ABC, RDEG and RRB before and after treatment. In keeping with extensive clinical use of this diuretic, the only side effect was a small hypokalaemia. A double-blind clinical trial is warranted to test the efficacy of bumetanide in FRX.

This single case report showed an improvement of the scores of each test used after 3 months of treatment. Double-blind clinical trials are warranted to test the efficacy of bumetanide in FRX.
 
 
Clinical observations have shown that GABA-acting benzodiazepines exert  paradoxical excitatory effects in autism, suggesting elevated intracellular chloride (Cl-)i and excitatory action of GABA. In a previous double-blind randomized study, we have shown that the diuretic NKCC1 chloride importer  antagonist bumetanide, that decreases (Cl-)i and reinforces GABAergic  inhibition, reduces the severity of autism symptoms. Here, we report results from an open-label trial pilot study in which we used functional magnetic  esonance imaging and neuropsychological testing to determine the effects of 10 months bumetanide treatment in adolescents and young adults with autism. We show that bumetanide treatment improves emotion recognition and  enhances the activation of  brain regions involved in social and emotional perception during the perception of emotional faces. The improvement of emotion processing by bumetanide reinforces the usefulness of bumetanide as a promising treatment to improve social interactions in autism.
 
My experience after 12 months of Bumetanide
Bumetanide continues to have a positive effect on Monty, aged 10 with ASD, which I would summarize as a marked increase in awareness or “presence” or a lack of “absence” from the world.  Improved social interactions may have followed, but are secondary.

My own impression is that the effect peaks and then reduces somewhat.  This also appears to be the case with NAC and Atorvastatin.  I think the body is adjusting to the new treatments, via feedback loops.  This is inevitable, it is just a matter of human physiology.  If the above MRI study shows a long term change in brain function, then great.
I hope that my future therapies will be more disease changing, this does look to be possible.  Early signs are promising. 

 
My experience of 12 months blogging
My doctor mother asked me over Christmas how many people have been reading my blog and acting on it.  The answer is about 6,000 page views a month, but I suspect less than 10 people have even tried Bumetanide, nobody has tried Atorvastatin, and a few tens have tried NAC.

I think people are frightened of drugs.  Supplements are OK and any kind of unusual diet is great.
I think if I proposed a diet of baked beans, fried eggs and bacon I would have a much bigger following. Luckily that was not my objective.

With the advent of the internet, simple drugs like diuretics are as easy to buy as supplements like NAC; I doubt you are going to get into trouble for having an unauthorized diuretic in the bathroom cabinet.
Supplements are not subject to the same manufacturing standards as drugs and there are pretty strange things sold as “supplements”.

I will continue to develop my own therapy for classic early onset autism and when I finish, I will patent it and produce it as an orphan drug.  Orphan drugs are for rare diseases, where there is no other treatment.  They have less daunting regulatory requirements, meaning you do not need $25 million to develop them. In the EU you need a serious condition affecting fewer than 5 in 10,000 people; across the EU that equates to 250,000 people.  If you narrowly define my target autism phenotype, with biomarkers you end up within this limit.
Unfortunately, if you want to patent something, you have to keep it secret.  I did discuss all this with the venture capital firm that commercializes the intellectual property of my old university plus that of Cambridge, Oxford and UCL. The conclusion was to either give it to the world for free, or to commercialize it.  Giving it for free clearly has zero impact, so it has to be Plan B.

So the blog continues, but it will not contain all the clever stuff.

Next steps
I have also been busy in the last twelve months, having taken my inspiration from the Frenchmen, Ben-Ari and Lemmonier.  I have had my own “breakthroughs”, by applying the research and some imagination.

While you cannot totally cure genuine autism, you can go a long way, far further than I would have dared to believe possible.
You can treat the most difficult issues such as absence, anxiety, aggression and SIB.  Odd behavioural traits like obsessions and compulsions can be greatly reduced.  The combined effect is definitely a much happier person.

I think there is much more possible in areas like mood, confidence, creativity, sociability and indeed cognitive performance.
Bumetanide was a very important first step, but in itself it is far from a “cure”.  In combination with some other safe drugs, the result will indeed be remarkable.
The final element will be time itself.  The human brain does not come ready programmed; the first few years of childhood are used to establish full brain function.  In autism, during these important first few years the brain was running in “safe mode”, all sorts of important connections were never made and some were lost.  The brain does remain plastic throughout life and so it has the potential to make some of these missing connections.
The drug treatment has to deal with oxidative stress, neuro-inflammation, several ion channel/transporter dysfunctions and the tricky area of central hormonal hypofunction/dysfunction.

Note that not all people with autism respond to Bumetanide. Only a large clinical trial will show what percentage are responders.  In the same way, I expect only a minority of those diagnosed with ASD by current psychiatric measures will respond to my drug; but it would be possible to identify them based on biomarkers and case histories. 


 

Sunday 22 December 2013

Autism Pathology as a Venn Diagram

Source: Peter Research                     

Notes
 
Oxidative stress increases neuro-inflammation
Neuro-inflammation increases oxidative stress
Both oxidative stress and neuro-inflammation contribute to central hormonal dysfunction,
e.g. stress reducing D2 levels that stop T4 converting to T3 in the brain


One year after starting my investigation, I thought it would be useful to sum up Classic
Autism in a simple form.  I chose a Venn diagram.  At school your kids probably have just 
two overlapping circles.  If you have four variables you need to use ellipses.  Where all four variables are in play, is the area where all four ellipses overlap.  This is untreated classic autism.
 
Once you successfully treat any of the four trouble areas (Neuro-inflammation, oxidative
stress, channelopathies and hormonal dysfunction in the brain) you can modify the disease
and move to a happier part of the diagram. 





Friday 20 December 2013

Amyloids, APP, ADAM17 and Autism



Tonsil biopsy in variant CJD, source: Wikipedia

Amyloid may sound like someone’s name, but in fact it is something rather sinister and is related to many brain disorders.  It appears that, at least in severe cases, they may be implicated in autism, or least the precursor is.
Proteins that are normally soluble undergo a process called amyloidosis, which makes them insoluble and allows deposits to accumulate in various organs, including the brain.  There are many known examples, including Alzheimer’s  and Mad Cow Disease (Creutzfeldt–Jakob disease).  A number of years ago there was a huge public health scare in the UK, when humans were affected by Mad Cow Disease, after eating the brains of cows in processed food.
Symptoms vary widely, depending upon where in the body amyloid deposits accumulate. Amyloidosis may be inherited or acquired.
The precursor to amyloid is naturally called  Amyloid Precursor Protein (APP).
APP exists in all of us and is not necessarily bad.  Its function is not fully understood (see later in this post). 

Alzheimer’s                           Autism

Affects female > Mmale                                   Affects male > female 

Brain atrophy                                                     Macrocephaly
                                                                              (enlarged brain in child)

Amyloid plaques  

Degenerative                                                      Decline followed by stable 

High αβ, low sAPPα                                           High sAPPα, low αβ

           
 
Amyloid Precursor Protein (APP)

The gene related to Amyloid Precursor Protein (APP), was only identified in 1987 and the biology surrounding it is only very partially understood.  Much of the experimental work is related to Alzheimer’s, but some of these researchers are also looking at implications for autism.
For the bold, here is a very recent paper on APP:-


A power-point style presentation is here:-

The research proved the hypothesis:-

APP metabolites follow nonamyloidgenic pathway (i.e., high sAPP, sAPPα, low Aβ 40) in brain tissue of children with autism, compared to age matched controls

Here is the data:-





 



 


For those of you who want to read a full paper by the same authors from Indianapolis, here it is:-
 

 
Terminology
Biologists do make their work sound very complicated; generally it is the terminology that may make it look unintelligible on first reading.  Just read it again and look up the confusing terms.  They also seem to have up to 5 different names for the same molecule.

Compared to other areas of science like Fluid Mechanics, which I had to study, and Wikipedia rather understated describes as “Fluid mechanics can be mathematically complex”,  biology is just a lot of knowledge; none is really intellectually challenging, at least not until the amyloids start growing.
Just use the amazingly up to date resources of Wikipedia.

  =  beta amyloid   = amyloid β-peptide     The most common isoforms are Aβ40 and Aβ42
βAPP = β-amyloid precursor protein = amyloid-β precursor protein  = AβPP

 sAPPα = soluble APPα = soluble amyloid precursor protein α

β-secretase = Beta-secretase 1  = BACE1 = beta-site APP cleaving enzyme 1 = beta-site amyloid precursor protein cleaving enzyme 1

 γ-secretase = Gamma secretase

Gamma secretase can cleave APP in any of multiple sites to generate a peptide from 39 to 42 amino acids long.

Generation of the 42  Aβ (amyloid β-peptides) that aggregate in the brain of Alzheimer's patients requires two sequential cleavages of APP.  Extracellular cleavage of APP by β-secretase (BACE) creates a soluble extracellular fragment and a cell membrane-bound fragment referred to as C99. Cleavage of C99 within its transmembrane domain by γ-secretase releases the intracellular domain of APP and produces Aβ (amyloid-β).
However a single residue mutation in APP reduces the ability of β-secretase to cleave it to produce amyloid-beta and reduces the risk of Alzheimers and other cognitive declines.
Inhibitors of amyloid deposition include the enzymes responsible for the production of extracellular amyloid such as β-secretase and γ-secretase inhibitors.  Currently the γ-secretase inhibitors are in clinical trials as a treatment for Alzheimer's disease.

 
Amyloid Precursor Protein
Amyloid precursor protein (APP) is an integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. Its primary function is not known, though it has been implicated as a regulator of synapse formation, neural plasticity and iron export. APP is best known as the precursor molecule whose proteolysis generates beta amyloid (Aβ), a 37 to 49 amino acid peptide whose amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease

Biological function
Although the native biological role of APP is of obvious interest to Alzheimer's research, thorough understanding has remained elusive.

Synaptic formation and repair
The most-substantiated role for APP is in synaptic formation and repair; its expression is upregulated during neuronal differentiation and after neural injury. Roles in cell signalling, long-term potentiation, and cell adhesion have been proposed and supported by as-yet limited research. In particular, similarities in post-translational processing have invited comparisons to the signaling role of the surface receptor protein Notch.
APP knockout mice are viable and have relatively minor phenotypic effects including impaired long-term potentiation and memory loss without general neuron loss. On the other hand, transgenic mice with upregulated APP expression have also been reported to show impaired long-term potentiation.
The logical inference is that because Aβ accumulates excessively in Alzheimer's disease its precursor, APP, would be elevated as well. However, neuronal cell bodies contain less APP as a function of their proximity to amyloid plaques. The data indicate that this deficit in APP results from a decline in production rather than an increase in catalysis. Loss of a neuron's APP may affect physiological deficits that contribute to dementia.

Iron export
A different perspective on Alzheimer's is revealed by a mouse study that has found that APP possesses ferroxidase activity similar to ceruloplasmin, facilitating iron export through interaction with ferroportin; it seems that this activity is blocked by zinc trapped by accumulated Aβ in Alzheimer's. It has been shown that a single nucleotide polymorphism in the 5'UTR of APP mRNA can disrupt its translation.
The hypothesis that APP has ferroxidase activity in its E2 domain and facilitates export of Fe(II) is possibly incorrect since the proposed ferroxidase site of APP located in the E2 domain does not have ferroxidase activity.
 
Hormonal regulation
The amyloid-β precursor protein (AβPP) and all associated secretases are expressed early in development and plays a key role in the endocrinology of reproduction – with the differential processing of AβPP by secretases regulating human embryonic stem cell (hESC) proliferation as well as their differentiation into neural precursor cells (NPC). The pregnancy hormone human chorionic gonadotropin (hCG) increases AβPP expression and hESC proliferation while progesterone directs AβPP processing towards the non-amyloidogenic pathway, which promotes hESC differentiation into NPC.
AβPP and its cleavage products do not promote the proliferation and differentiation of post-mitotic neurons; rather, the overexpression of either wild-type or mutant AβPP in post-mitotic neurons induces apoptotic death following their re-entry into the cell cycle. It is postulated that the loss of sex steroids (including progesterone) but the elevation in luteinizing hormone, the adult equivalent of hCG, post-menopause and during andropause drives amyloid-β production and re-entry of post-mitotic neurons into the cell cycle.

Arthritis
Recently, amyloid precursor protein (APP) origin was demonstrated with arthritogenic animals. The source noted is breakdown of immune complexes, where the amyloid aggregates are left degraded and bind together to form coil like structures that are not reabsorbed. Also, it induces secondary inflammation, which may cause local damage.

ADAM17
ADAM17 is understood to be involved in the processing of tumor necrosis factor alpha (TNF-α) at the surface of the cell. This process, which is also known as 'shedding', involves the cleavage and release of a soluble ectodomain from membrane-bound pro-proteins (such as pro-TNF-α), and is of known physiological importance. ADAM17 was the first 'sheddase' to be identified, and is also understood to play a role in the release of a diverse variety of membrane-anchored cytokines, cell adhesion molecules, receptors, ligands and enzymes.


Conclusion
Even though it does sound complicated, there are some conclusions.

Amyloid Precursor Protein (APP) can either be processed towards so-called amyloidogenic pathways in the brain that lead to Alzheimer’s, or it can follow so-called non-amyloidogenic pathways, as appears to be the case in autism.  The direction taken seems to depend on α, β and γ–secretases, which are themselves regulated by neurotransmitters and other signalling molecules.
But why are there elevated levels of APP in autism?

As is often the case in autism research, some are thinking biomarker and some are thinking about therapeutic interventions.  I am with the latter.
By the way, now we have dealt with Amy, what about Adam? (the final chart above)
Functional ADAM17 has been documented to be expressed in the human colon, with increased activity in the colonic mucosa of patients with ulcerative colitis, a main form of inflammatory bowel disease.  But remember, that paper by Wakefield was retracted and so there should not be evidence linking autism with colitis.  Tell Adam to keep quiet.


ADAM17 = ADAM metallopeptidase domain 17  =  TACE  = (tumor necrosis factor-α-converting enzyme) = TNF α-converting enzyme 

TNF are a group of cytokines that cause cell death.

 

 
 

Wednesday 18 December 2013

An Acquired Channelopathy




Source:Wikipedia



For the psychologists among you, and self-taught ABA parents like me, you will know what is a meant by an "acquired behaviour".  So once a child has learnt a behaviour, that resulted in something the child found rewarding, the behaviour will repeat.

Once learnt, it is difficult to get rid of unwanted acquired behaviours.  An example in autism would be self-injury.

In an earlier post, we learnt that children at risk of developing asthma, if identified and treated with a mast cell stabilizer, could be prevented from developing asthma.  Once you have had one asthma attack, more will follow.

Today, I learnt that you can acquire a channelopathy, that is to say an ion-channel disease that is normally caused by your genes.

"We do know that in some forms of epilepsy, once someone has a seizure they tend to have more. Our findings from this study suggest that something about the brain changes that can lead to this increased tendency to have a seizure. Our study shows that an important change occurs in calcium channels that help to transmit this abnormal activity throughout the brain."
 
This means, at least in some types of epilepsy, the first seizure permanently changes (damages) the brain.  Thereafter, the affected ion channels function as if that person had a gene mutation. 

This is important for the study of autism because we know that there are ion-channel abnormalities.  If you could identify these channelopathies, that would be the first step towards treating them, and reversing the associated behaviours.

If these channelopathies were not predetermined by genetics, rather some were acquired, that would be very important.  Then you could look at how, when and why they were acquired.

It might be that the channelopathies caused by rare inborn genetic mutations associated with conditions like Timothy Syndrome, are not so rare after all.  It is just that the channel mutated without the "faulty" gene.  So genetic testing will not identify it.





Tuesday 17 December 2013

Autism & Self-Injurious Behaviour (SIB)


 

For parents more severely affected by autism, one of the most difficult things to deal with is anger, aggression and self-injurious behaviour (SIB).  SIB is sometimes rather politely referred to as challenging behaviour.
In the case of Monty, aged 10 with ASD, we have overcome these problems (for now at least); but for other people have to struggle on with them, on a daily basis. 
SIB can affect any person with autism, whether they are severely, moderately or mildly affected otherwise.  Left untamed, I am reliably informed, it may return in adulthood.  
So, for those people, who do not want to follow the “novel”, but science-based, interventions discussed elsewhere in this blog, here is what the experts have to say:-
 
From the US  (an excellent paper) :-
  
From the UK:-

 From Canada:-

 

 

 

 

Monday 16 December 2013

Comorbidities in Autism and the Curious Cleaning Lady


Regular readers will know that I believe in the value of investigating the comorbidities of autism. 

We have a cleaning lady who comes each week to help keep our house in order.  She also understands the value of comorbidities. She is one of my independent observers, in changes in the behaviour of Monty, aged 10 with ASD.  She has a friend, whose husband was diagnosed with early-onset Alzheimer’s.
Alzheimer’s is not autism, but they are both examples of brain damage.

Still in his early 50s, the husband does not recognize his children and cannot leave home.  The expert Professor, treating him privately, was not halting the rapid decline.
So the cleaning lady asks me about all my investigations and decides that she might as well tell her friend.  She decided to suggest the antioxidant NAC and the cholinergic stimulant nicotine.

Well, after NAC, the husband was able to make it to the WC and do his business.  A small step forward.
After a day with the nicotine patch, things really changed so much that the family decided that they should seek a second opinion, this time from a doctor, yet to publish a book.

Doctor number two decided that it is not Alzheimer’s after all, and the prescribed medicines of the last three years were only making things worse.  And the new therapy? Nicotine patches.

Conclusion
The conclusion is self-evident. 

The next related conditions I will be investigating are cluster headaches, febrile seizures and absence seizures.

 

 

Wednesday 11 December 2013

Assessment Week at School and Cognitive Enhancement in Autism





 In earlier posts I have touched upon the problems of clinical trials in autism:-
·        Highly subjective, or ineffective, rating scales for autistic behaviours

·        Lack of biomarkers, or any other marker, to target a specific sub-types(phenotypes of autism

·        Very small sample sizes and often amateur execution, meaning the results cannot be replicated

I think one of these problems has a ready solution, at least for verbal primary school children with ASD. 

Assessment Week
Last week, Monty aged 10 with ASD, had assessment week at school.  The academic subjects he participates in, are Maths, English and Science.  We have chosen to skip Geography, History and French.  Monty already has another second language.
Following the tests at school, I decided to make a test of my own.  I stopped all of my therapies and waited to see what would happen and if anyone would notice.

The first therapy I had to reintroduce was bumetanide, which in his case makes him far more aware of himself and his surroundings; it makes him more “present”.  The reason for this was, for the first time in years, on day one, he forgot to go to the toilet and peed in his pants.  A coincidence?  I think not.  Also, when I told him that I was going out, instead of the expected “see you later, Dad” I got “see you Monday”.
Then the next day having restarted bumetanide we drive to school.  I hear lots of relevant comments like “There’s a Peugeot lion taxi car”, “The soldier has a gun, that fires bullets”.  The day before there were no comments at all.

But the day at school was not so good; all the stereotypy with his hands and fingers returned, so while the day was not hard for his assistant, she said it was hard for Monty.  He was commenting, like the things he could see through the window of his classroom, but work was not good.  Handwriting degenerated to oversized sloppy writing, that did not follow the lines on the paper. In the afternoon, I reinstated NAC, just in time for the arrival of his assistant who works with him at home, following an ABA-style programme.  During the rest of the afternoon, all stereotypy with his hands and fingers disappeared, just as expected.
Today, I met the school teacher and not only were his grades As and Bs, but he finished his tests much faster than most of the other children.  This is remarkable, because he has never received any real academic grades before; the teachers did not think it fair to give him grades.  I should point out that Monty is at least 2 years older than his classmates; but then he was pretty much entirely non-verbal until he was 4 years old, so he has lost a lot of learning time.

The relevance of all this is that while psychological and behavioral testing is very subjective, basic cognitive testing, as practiced in schools around the world, is very well understood, fair and easy to replicate.
With children who are verbal, can read a bit, write and do some very basic maths, a simple cognitive test, measuring these basic skills, assessing both  accuracy and speed would produce a pretty good surrogate index of cognitive functioning.  You could easily use such an index to measure the effectiveness of a drug in autism.  If large scale trials were done in Special Schools, this could work really well.  One week the class is on the placebo and the next week on the trial drug.  Then you could have trials with several hundred participants.

I think coming up with measurements for things like “social withdrawal”, as is currently done, is far too esoteric.  Let’s go back to the three Rs (reading, writing and arithmetic).

Nootropic drugs
I find it more than a coincidence that several of the autism drugs I am investigating, happen to be classed as nootropic.  Nootropic drugs are cognitive enhancers.

I have demonstrated that as you improve autism, you increase cognitive function; but perhaps as you improve cognitive function, you improve autism.  If this were true, it would open up new avenues for investigation.
There is an underground scene of cognitive enhancers, and if you probe the internet, you will readily find what works and what does not.

On the serious research front, here is a recent paper that is very comprehensive:-