“We did genetic testing and it came back clear!” Well your VCF file probably says otherwise!

 

In the TikTok/Instagram world where many people live these days, everything is kept very simple. The real world is becoming the alternative reality.

Over the years, many people have sent me their genetic testing results. Nowadays we have moved on to whole genome sequencing (WGS), which generates vast amounts of data and is pretty much as good as it gets. Vast amounts of data brings with it the problem of how to filter through it and not miss something critical.

I have written many times that parents who have had genetic testing carried out on their child should ask for the full list of mutations, not just those on the lab’s list for autism. In the case of whole exome sequencing (WES), this could produce a list of 10 to 30 mutations, which might well include an ion channel, or a similar variant, that is actually relevant to autism.  

More and more parents are doing this or even repeating the WGS elsewhere and then getting a very different interpretation, with a likely causal gene identified.

 

“We did genetic testing and it came back clear!”

I am sorry to disappoint the TikTokers, but nobody’s WGS results can come back clear.

 

What is whole genome sequencing (WGS)?

Scientists have put together a reference genome, based on the results of many different real people. 

In WGS, blood or saliva is used to sequence the entire genome of the patient, and then it is automatically compared to the reference genome. Tens of thousands to millions of variants will be identified. They all end up in the VCF (Variant Call Format) file.

 

The VCF (Variant call format) file

The VCF file is generated by special software. It contains details about the genetic variants.

 

Annotated VCF file

More automation then looks up each of the detected variants to see if they are already listed in databases, as being known to cause problems. If the variant has not been listed in these databases, it will not be highlighted.

These days most labs will provide the annotated VCF file and it can be huge.

 

The role of the geneticist or ChatGPT

The geneticist is then supposed to take the annotated VCF file and filter the results based on the clinical condition of the patient.

Results are categorized as:

·        Pathogenic

·        Likely pathogenic

·        Variant of uncertain significance

·        Likely benign

·        Benign

In theory, the geneticist’s job is to translate the vast and complex information from genetic tests into actionable insights for diagnosis, treatment, and genetic counselling, ensuring both precision and empathy in patient care.

He/she should check whether the identified variant explains the patient's specific symptoms (e.g., developmental delay, speech impairment, intellectual disability).

If multiple variants are identified, consider whether they might interact.

Some individuals may have only one variant, while others may carry several genetic changes that contribute to their condition.

 

How come there are so many apparently sloppy geneticists?

Doctors like to deal with certainties and the geneticist has to avoid diagnosing a gene as causal, when there is a chance it actually is not. They also know that there are almost no genes related to autism that they can treat. There is no incentive a take a stab at causality, when they know they cannot offer any follow-on treatment. Contrast that with the parent's perspective looking for any clues.

Genetics is actually all about probabilities, much more than certainties. So, if you have 3 mutations that are each individually “survivable”, the combination might be causal.

Here is an example:

Imagine a scenario where:

• Mutation 1: Causes a minor disruption in protein folding (survivable).
• Mutation 2: Impairs a metabolic enzyme function (survivable).
• Mutation 3: Affects a signaling pathway that slightly reduces cellular repair efficiency (survivable).

Each of these mutations, on their own, may not lead to a disease. However, when combined, these disruptions might overwhelm cellular systems and cause a disease phenotype (for example, a neurodegenerative condition), as the cumulative effect of these disruptions could impair essential cellular functions beyond a survivable threshold.

  

Not enough people with autism submit WGS data

I would think you need to have the WGS data from at least a million people with an autism diagnosis, from mild to severe, to be pretty sure you have identified the majority of causal mutations. Many of these causal mutations will actually be combinations of a few different genes - it would get very complicated. 

The number of people with autism currently included in the reference databases so far is tiny.  It is biased towards those with profound single-gene autism.

We really need to know about polygenic autism, which accounts for the vast majority of cases. Those cases range from profound to trivial.

I think that if I were in charge, I would tell people that if they want an autism diagnosis, they need to provide a saliva sample. No sample, no diagnosis. The test can be anonymous, if people prefer, so there is nothing to fear. At least this would reduce the waiting time for diagnosis!

  

TikTok autism

On social media you get a lot of self-diagnosed autism, but you also get some Moms/Mums of kids with profound autism.

I saw one today who has 3 sons and 1 daughter, all with profound autism. She says it cannot be genetic, because the geneticist did not find a causal gene.  In theory she might be right. Perhaps there is an environmental explanation, maybe the babies were all exposed to the same toxic environment (food, water, air, a high voltage power cable over the house …)

More likely, the geneticist did not do his job. Or, the kids have mutations that have not yet been added to the list of causal genes. The list grows every day. If she used a good provider, like GeneDX, and she ticked a box on the form, then they may come back to her in 5 years’ time and tell her that one of her kids’ mutations is now recognized as causal. This happened to one reader of this blog.   

My tip would be to ask for the Annotated VCF file and get ChatGPT to analyse it for anything that might explain profound autism.

It looks like any computer-savvy middle-aged person can do this; no prior experience needed!

 

Conclusion

I was pleasantly surprised to hear from several readers recently who followed my suggestion to dig deeper into the results of their child’s genetic testing. They all found something valuable, hidden away. Perhaps you wouldn’t contact Peter if you didn’t find something of use!

To analyze genetic data effectively, you will need the paid version ChatGPT Plus (GPT-4). While it is powerful, it does have processing limits. For example, processing a large VCF file requires breaking it into smaller, manageable parts. Fortunately, ChatGPT can guide you through this process.

If you were doing this as a professional service, you would be better off using GPT-4 via API. This tool, created by the same company, is designed for heavy data processing rather than conversational interaction.

When it comes to genetic forms of autism with approved drug therapies, there seem to be only two: 

·        Tuberous Sclerosis Complex (TSC1 or TSC2 Mutation): Treated with Everolimus (Afinitor) in the US, Canada, EU, UK, and Australia. 

·        Rett Syndrome (MECP2 Mutation): Treated with Trofinetide (Daybue) in the US and Canada if you have the money.

This highlights why geneticists focus on diagnosis rather than treatment. 

Unofficially, the possibilities for treatment are extensive, limited only by creativity and emerging research. Here again, ChatGPT can do much of the work for you.

P.S.  TikTok, Instagram and Facebook can be fun, but for something factual, better stick to ChatGPT or similar services.

P.P.S. I do not have shares in OpenAI, who own ChatGPT 

Genetic testing results

Click on the picture above to read about the upcoming event in London. There are familiar faces appearing, like Agnieszka, Dr Boles and indeed me.

 

I am quite often sent genetic testing results. There are many types of tests ranging from inexpensive tests looking at SNPs to the expensive WES or WGS tests.

SNP = Snip = Single Nucleotide Polymorphism = a tiny genetic spelling mistake

WES = Whole Exome Sequencing

WGS = Whole Genome Sequencing

There is a small industry based around selling expensive supplements for SNPs.

We all carry thousands of SNPs and I think these tests may often raise issues that are not causal.  The results from WGS or WES can be much more insightful.  A good example being in the comment recently posted on this blog.

 

I've been following your blog for many years, it's a real blessing and the perfect place to come and read for us, parents of ASD kids. My boy, 9, has non-regressive autism, is largely non verbal (one word sentence) and has pronounced OCD symptoms (similar to excoriating disorder, but aimed at the environment), hyperactivity and severe gut problems, recurrent vomitting, gastroparesis, etc. The only thing that visibly stopped the hyperactivity and inappropriate laughing and helped him sit for longer periods of time and read his books or watch whole movies was 0.5/kg mg Naltrexone daily, as advised by this paper https://pubmed.ncbi.nlm.nih.gov/16735648/. Lower doses saw the OCD creep back. As for his WGS test results, I've found relevant the fact that he has four pathogenic mutations in the EIF4EBP1, also a de novo mutation in the PIK3R1 gene and multiple other mutations in the STAT3, HTR3a, MAPT and also HLA-DRB1, HLA-DQA1, HLA-A, HLA-B, HLA-C, NRG1, NRG2, SCN4a, CACNA1S genes, amongst many others. We recently tried a course of Azythromycin for immuno-modulation, which saw his OCD reduced further, also his academic interest and focus increased visibly. He responds very well to Ibuprofen, AlkaSeltzer gold, Propranolol, Sytrinol and Cromolyn, but a quite long trial of Bumetanide two years ago did nothing for him. After all trials of various protocols and individual drugs, his gut is still bad, very often food seems to have major difficulty to pass though his digestive tract, no matter how finely tuned his diet is or how many prokinetics he takes. Given your extensive knowledge, I've always wondered what your take on the underlying problem/genetic pathway might be in his case (microglial activation, MTOR activation, perhaps?) and what drugs/cocktail of drugs might work best for his specific genetics and symptoms. He is a smart boy, has self-taught reading, loves music and masters his iPAD like a pro and, unlike what we know about autism, loves being around people. I cannot give up on him. We live in the UK, not the best place to even talk about treatments for autism. Please, if it's not too much to ask, tell me what other medications you thing it might boost his cognition further and help him start talking and develop more skills. Sorry for the long post. And thank you for any advice and ideas you might have to offer.

 

It would be useful to know which of the above mutations are present in at least one of the parents.  There so many possibly causal mutations here; I expect some are actually not relevant. In other words, it is not as scary at it may appear to be.

I do like to start with the easy part, which will be the ion channels.  Dysfunctions in ion channels (channelopathies) are often treatable with existing drugs and there is a great deal of information on each one.

 

CACNA1S

This gene encodes the calcium channel Cav1.1.

This is known as an L type calcium channel, the other ones being Cav1.2 and Cav1,3 and Cav1.4.

These ion channels are extremely important to how your brain works.  Because they also play a role in how your heart works, numerous drugs have been developed, some are more specific to one type of channel (Amlodipine for Cav1.3, Verapamil for Cav1.2).

The individual channels interact with other sub-types, so a mutation in one sub-type can affect other subtypes.

Very interesting in this case are the GI problems. There were efforts made a few years ago to develop R-verapamil as a drug to treat IBS/IBD under the name of Rezular. Some readers of this blog have reported that the only thing that resolves their child’s GI problems is an L-type calcium channel blocker.

Note Memantine, which is an Alzheimer’s drug that was subject to a very large autism clinical trial in the US.  The trial was deemed a failure, but one reader told me that Memantine is the only drug she had found that solved her child’s GI problems.  Memantine has several different modes of action, and a little reported one is blocking L-type calcium channels.

 

https://www.mdpi.com/1648-9144/49/9/64

Conclusions. Our results suggest that the neuroprotective effect of memantine could arise not only through the inhibition of the NMDA receptor current but also through the suppression of the L-type Ca²⁺ current.   

 

You might expect/hope a geneticist would suggest treatment with a drug like Verapamil.

  

SCN4a

This gene encodes the sodium ion channel Nav1.4.

This is one of the genes associated with Hypokalemic Periodic Paralysis (HPP), that was covered extensively in this blog. Interestingly the above Cav1.1 is also associated with Hypokalemic Periodic Paralysis (HPP).

The other genetic cause of HPP is KCNJ2 (an inward-rectifier potassium channel Kir2.1).

The immediate recovery therapy is drinking a potassium supplement.

A common preventative measure is acetazolamide (Diamox). This drug has also been covered in previous posts. The proposed mechanism is that it “increases the flow of potassium” – not sure what that is supposed to mean.

Some common anti-epilepsy drugs block Nav1.4 (Lamotrigine, Phenytoin etc).

All of the above-mentioned drugs have been used in autism. In specific cases they have shown a benefit.

You could ask your doctor to cautiously try them one by one.

Interestingly, the drug that seems to help many with sound sensitivity is Ponstan.  This cheap drug that affects the flow of potassium ions was proposed by Knut Witkowski as a therapy for 2-3 year olds to prevent non-verbal severe autism. 

 

EIF4EBP1

Here you mention there are 4 pathogenic mutations.

This gene is a real mouthful, but regular reader might recall the odd looking eIF4E part appearing in some previous posts

“This gene encodes one member of a family of translation repressor proteins. The protein directly interacts with eukaryotic translation initiation factor 4E (eIF4E), which is a limiting component of the multi subunit complex that recruits 40S ribosomal subunits to the 5' end of mRNAs. Interaction of this protein with eIF4E inhibits complex assembly and represses translation. This protein is phosphorylated in response to various signals including UV irradiation and insulin signaling, resulting in its dissociation from eIF4E and activation of cap-dependent mRNA translation.”

eIF4E inhibitors for Autism – Why not Ribavirin?

 

As you can see in the above post there are numerous ways to block elF4E. It is possible that the 4 mutations in your gene EIF4EBP1 could have the reverse effect in which case you would want to activate elF4E, not block it.

On the list, in my post above, is quercetin which is OTC and simple to try.

 

PIK3R1

A mutation in this gene can alter the PI3K/AKT/mTOR signaling pathway.

If this gene is causing a problem you might see some facial features a triangular face, a prominent forehead, small chin with a dimple, a loss of fat under the skin, prominent ears, hearing loss and delayed speech.

A mutation in this gene can lead to SHORT syndrome, which hopefully your pediatrician will have heard of.

 https://rarediseases.info.nih.gov/diseases/7633/short-syndrome

 

STAT3

STAT3 plays a key role in the immune system and elsewhere.

You can either have too much or too little STAT3.

In lay terms the immune system might end up either over-activated (hence benefiting from Ibuprofen and Cromolyn sodium) or under activated.

The immunomodulatory probiotics prescribed by gastroenterologists might be worth a try.

Lactobacillus rhamnosus GG

Lactobacillus plantarum 299v 

 

This might well reduce GI problems as well.

  

HTR3a 

This gene encodes subunit A of the type 3 serotonin receptor. It has lots of effects, but it may contribute to the vomiting.

It is associated with:

• Motion sickness
• Irritable bowel syndrome
• Social phobia
• Serotonin syndrome

For gastroparesis (impaired stomach's motility) the good drug seems to be Domperidone, which you should be able to get for free from your NHS doctor.

Another very popular therapy for gut dysbiosis of all kinds in some countries, but not the UK, is sodium butyrate. This has been mentioned in previous posts. It is an OTC supplement that will produce butyric acid in the gut and it helps restore a healthy mucosa. If you eat lots of fiber and have a healthy microbiome you would produce butyric acid naturally. The cheapest place in Europe to buy it is Poland, where they sell a product called Intesta Max (a weaker version is Intesta).  In the UK it is 3 times more expensive. Making friends with a Pole will save you money.

 

MAPT

The MAPT gene makes tau proteins.  There is a class of disease called tauopathy.

Tau Reduction Prevents Key Features of Autism in Mouse Models

 

Tau: A Novel Entry Point for mTOR-Based Treatments in Autism Spectrum Disorder?

 

As with the PIK3R1 mutation this will lead you to the idea of targeting mTOR signalling. You can inhibit this with Rapamycin, which has been used in autism.

 

Rapamycin/Sirolimus Improves the Behavior of an 8-Year-Old Boy With Nonsyndromic Autism Spectrum Disorder

 

One UK reader did get Everolimus prescribed on the NHS, but that was because the child was diagnosed with a genetic disorder called TSC. Several readers of this blog have tried Rapamycin as used in the Chinese case study.

If you do not have an over activated immune system, Rapamycin will cause the problem of an underactive immune system.

  

HLA-DRB1, HLA-DQA1, HLA-A, HLA-B, HLA-C,

 These genes all play a role in the immune system.

The human leukocyte antigen (HLA) system is a complex of genes in humans which encode cell-surface proteins responsible for regulation of the immune system.

The immune system uses the HLAs to differentiate self cells and non-self cells. Any cell displaying that person's HLA type belongs to that person and is therefore not an invader.

 

HLA Immune Function Genes in Autism

The human leukocyte antigen (HLA) genes on chromosome 6 are instrumental in many innate and adaptive immune responses. The HLA genes/haplotypes can also be involved in immune dysfunction and autoimmune diseases. It is now becoming apparent that many of the non-antigen-presenting HLA genes make significant contributions to autoimmune diseases. Interestingly, it has been reported that autism subjects often have associations with HLA genes/haplotypes, suggesting an underlying dysregulation of the immune system mediated by HLA genes. Genetic studies have only succeeded in identifying autism-causing genes in a small number of subjects suggesting that the genome has not been adequately interrogated. Close examination of the HLA region in autism has been relatively ignored, largely due to extraordinary genetic complexity. It is our proposition that genetic polymorphisms in the HLA region, especially in the non-antigen-presenting regions, may be important in the etiology of autism in certain subjects.

One specific HLA gene has been studied in autism.

 Inheritance of HLA-Cw7 Associated With Autism Spectrum Disorder (ASD)

Autism spectrum disorder (ASD) is a behaviorally defined disorder that is now thought to affect approximately 1 in 69 children in the United States. In most cases, the etiology is unknown, but several studies point to the interaction of genetic predisposition with environmental factors. The immune system is thought to have a causative role in ASD, and specific studies have implicated T lymphocytes, monocytes, natural killer (NK) cells, and certain cytokines. The human leukocyte antigen (HLA) system is involved in the underlying process for shaping an individual’s immune system, and specific HLA alleles are associated with specific diseases as risk factors. In this study, we determine whether a specific HLA allele was associated with ASD in a large cohort of patients with ASD. Identifying such an association could help in the identification of immune system components which may have a causative role in specific cohorts of patients with ASD who share similar specific clinical features. Specimens from 143 patients with ASD were analyzed with respect to race and ethnicity. Overall, HLA-Cw7 was present in a much greater frequency than expected in individuals with ASD as compared to the general population. Further, the cohort of patients who express HLA-Cw7 shares specific immune system/inflammatory clinical features including being more likely to have allergies, food intolerances, and chronic sinusitis as compared to those with ASD who did not express HLA-Cw7. HLA-Cw7 has a role in stimulating NK cells. Thus, this finding may indicate that chronic over-activation of NK cells may have a role in the manifestation of ASD in a cohort of patients with increased immune system/inflammatory features.

 

The therapeutic implication would be to look at immunomodulatory therapy.

At the simple level you have NSAIDs like Ibuprofen, but then you have the more potent drugs used to treat psoriasis, arthritis, IBD etc.

If you saw Dr Arthur Krigsman, the autism gastroenterologist, I guess he would prescribe Humira.  This is an injection you take every few weeks.  That very well might help your son in many ways. He does also come to Europe for consultations. You would need a colonoscopy.

Some British parents take their autistic kids with GI problems to Italy for treatment. You could ask the Thinking Autism charity who they go to see. One of these doctors presented at their conference in London in 2019.  He used some of Krigsman’s slides in his presentation.

 

NRG1, NRG2

Neuregulin 1 and 2 are implicated in brain disorders. NRG1 is well known as a schizophrenia gene, but it has been shown to be miss-expressed in autism as well.

NRG2 also plays a role in many neurological conditions.  

Neuregulins in Neurodegenerative Diseases 

The downstream effect of NRG1 is on epidermal growth factor (EGF). There are expensive cancer drugs like Lapatinib that are inhibitors of EGFR. 

As I have written in my blog, disturbed growth factors is a recurring feature of autism. This is why son many autism genes are also cancer genes. Don’t worry, this does not mean everyone with autism is going to get cancer.

 

Conclusion

Try and find a doctor who is interested to treat your son.

I think you will make great strides by treating the GI problems that you see every day.

I did meet an UK autism mother at that conference in London in 2019 who was told by her doctor that her son’s GI problems would not be treated in the UK and she should look abroad. She went to Italy and solved his problems.  It sounds so bizarre, I would not have believed it to be possible, had I not been talking directly to the mother.  I did talk to the Italian gastroenterologist at that same event.  Contact Thinking Autism and ask who was the Italian who presented in 2019.

Genetic Mutations vs Differentially Expressed Genes (DEGs) in Autism

 

Genes make proteins and you need the right amount in the right place

at the right time.

I should start this post by confessing to not having carried out genetic testing on Monty, now aged 18 with autism.  When I did mention this to one autism doctor at a conference, I was surprised by her reply:- “ You did not need to.  Now there’s no point doing it”.

I got lucky and treated at least some of Monty’s Differentially Expressed Genes (DEGs) by approaching the problem from a different direction.

People do often ask me about what diagnostic tests to run and in particular about genetic testing.  In general, people have far too high expectations regarding such tests and assume that there will be definitive answers, leading to effective therapeutic interventions.

I do include an interesting example today where parent power is leading a drive towards an effective therapeutic intervention in one single gene type of autism.  The approach has been to start with the single gene that has the mutation and look downstream at the resulting Differentially Expressed Genes (DEGs). The intervention targets one of the DEGs and not the mutated gene itself.

This is a really important lesson.

It can be possible to repurpose existing drugs to treat DEGs quite cheaply.  Many DEGs encode ion channels and there are very many existing drugs that affect ion channels.

Entirely different types of autism may share some of the same DEGs and so benefit from the same interventions.

 

Genetic Testing 

Genetic testing has not proved to be the holy grail in diagnosing and treating autism, but it remains a worthwhile tool at a population level (i.e. maybe not in your specific case).  What matters most of all are Differentially Expressed Genes (DEGs), which is something different.

A paper was recently published that looked into commercially available genetic testing.  Its conclusion was similar to my belief that you risk getting a “false negative” from these tests, in other words they falsely conclude that there is no genetic basis for the person’s symptoms of autism. 

 

Brief Report: Evaluating the Diagnostic Yield of Commercial Gene Panels in Autism

Autism is a prevalent neurodevelopmental condition, highly heterogenous in both genotype and phenotype. This communication adds to existing discussion of the heterogeneity of clinical sequencing tests, “gene panels”, marketed for application in autism. We evaluate the clinical utility of available gene panels based on existing genetic evidence. We determine that diagnostic yields of these gene panels range from 0.22% to 10.02% and gene selection for the panels is variable in relevance, here measured as percentage overlap with SFARI Gene and ranging from 15.15% to 100%. We conclude that gene panels marketed for use in autism are currently of limited clinical utility, and that sequencing with greater coverage may be more appropriate.

 

To save time and money, the commercial gene panels only test genes that the company defines as autism genes.  There is no approved list of autism genes. 

You have more than 20,000 genes and very many are implicated directly, or indirectly, in autism and its comorbities. To be thorough you need Whole Exome Sequencing (WES), where you check them all.  

There are tiny mutations called SNPs ("snips") which you inherit from your parents; there are more than 300 million known SNPs and most people will carry 4-5 million.  Some SNPs are important but clearly most are not.  Some SNPs are very common and some are very rare. 

Even WES only analyses 2% of your DNA, it does not consider the other 98% which is beyond the exome.  Whole Genome Sequencing (WGS) which looks at 100% of your DNA will be the ideal solution, but at some time in the future.  The interpretation of WES data is often very poor and adding all the extra data from WGS is going to overwhelm most people involved. 

Today we return to the previous theme of treating autism by treating the downstream effects caused by Differentially Expressed Genes (DEGS).

Genetics is very complicated and so people assume that is must be able to provide answers. For a minority of autism current genetics does indeed provide an answer, but for most people it does not.

Early on in this blog I noted so many overlaps between the genes and signaling pathways that drive cancer and autism, that is was clear that to understand autism you probably first have to understand cancer; and who has time to do that!

Some people’s cancer is predictable. Chris Evert, the American former world No. 1 tennis player, announced that she has ovarian cancer.  Her sister had exactly the same cancer.  Examining family history can often yield useful information and it is a lot less expensive that genetic testing.  Most people’s cancer is not so predictable; sure if you expose yourself to known environmental triggers you raise its chances, but much appears to be random.  Cancer, like much autism, is usually a multiple hit process. Multiple events need to occur and you may only need to block one of them to avoid cancer. We saw this with a genetic childhood leukemia that you can prevent with a gut bacteria. 

Learning about Autism from the 3 Steps to Childhood Leukaemia

What is not random in cancer are the Differentially Expressed Genes (DEGs).

We all carry highly beneficial tumor suppressing genes, like the autism/cancer gene PTEN.  You would not want to have a mutation in one of these genes.

What happens in many cancers is that the individual carries two good copies of the gene like PTEN, but the gene is turned off. For example, in many people with prostate cancer, the tumor suppressor gene PTEN is turned off in that specific part of the body.  There is no genetic mutation, but there is a harmful Differentially Expressed Gene (DEG). If you could promptly turn PTEN expression back on, you would suppress the cancer.

Not surprisingly, daily use of drugs that increase PTEN expression is associated with reduced incidence of PTEN associated cancer.  Atorvastatin is one such drug.

 

DEGs are what matter, not simply mutations

 

In many cases genetic mutations are of no clinical relevance, we all carry several on average.  In some cases they are of immediate critical relevance.  In most cases mutations are associated with a chance of something happening, there is no certainty and quite often further hits/events/triggers are required.

A good example is epilepsy. Epilepsy is usually caused by an ion channel dysfunction (sodium, potassium or calcium) that is caused by a defect in the associated gene. Most people are not born with epilepsy, the onset can be many years later.  Some parents of a child with autism/epilepsy carry the same ion channel mutation but remain unaffected. 

 

Follow the DEGs from a known mutation 

There is a vanishingly small amount of intelligent translation of autism science to therapy, or even attempts to do so.  I set out below an example of what can be done.

 

Pitt Hopkins (Haploinsufficiency of TCF4) 

The syndrome is caused by a reduction in Transcription factor 4, due to mutation in the TCF4 gene.  One recently proposed therapy is to repurpose the cheap calcium channel blocker Nicardipine. Follow the rationale below.

 

↓  means down regulated

↑ means up regulated

1.     Gene/Protein TCF4 (Transcription Factor 4) ↓↓↓↓

2.     Genes SCN10a  ↑↑    KCNQ1 ↑↑

3.     Encoding ion channels  Na_v1.8   ↑↑     K_v7.1   ↑↑

4.     Repurpose approved drugs as inhibitors of K_v7.1 and Na_v1.8 

5.     High throughput screen (HTS) of 1280 approved drugs.

6.     The HTS delivered 55 inhibitors of K_v7.1 and 93 inhibitors of Na_v1.8

7.     Repurposing the Calcium Channel Inhibitor Nicardipine as a Na_v1.8 inhibitor 

           

The supporting science: 

Psychiatric Risk Gene Transcription Factor 4 Regulates Intrinsic Excitability of Prefrontal Neurons via Repression of SCN10a and KCNQ1

  

Highlights

•TCF4 loss of function alters the intrinsic excitability of prefrontal neurons 

•TCF4-dependent excitability deficits are rescued by SCN10a and KCNQ1 antagonists 

•TCF4 represses the expression of SCN10a and KCNQ1 ion channels in central neurons 

•SCN10a is a potential therapeutic target for Pitt-Hopkins syndrome

  

Na_v1.8 is a sodium ion channel subtype that in humans is encoded by the SCN10A gene

K_v7.1 (KvLQT1) is a potassium channel protein whose primary subunit in humans is encoded by the KCNQ1 gene.

  

Transcription Factor 4 (TCF4) is a clinically pleiotropic gene associated with schizophrenia and Pitt-Hopkins syndrome (PTHS).  

SNPs in a genomic locus containing TCF4 were among the first to reach genome-wide significance in clinical genome-wide association studies (GWAS) for schizophrenia  These neuropsychiatric disorders are each characterized by prominent cognitive deficits, which suggest not only genetic overlap between these disorders but a potentially overlapping pathophysiology.

We propose that these intrinsic excitability phenotypes may underlie some aspects of pathophysiology observed in PTHS and schizophrenia and identify potential ion channel therapeutic targets.

Given that TCF4 dominant-negative or haploinsufficiency results in PTHS, a syndrome with much more profound neurodevelopmental deficits than those observed in schizophrenia, the mechanism of schizophrenia risk associated with TCF4 is presumably due to less extreme alterations in TCF4 expression at some unknown time point in development

The pathological expression of these peripheral ion channels in the CNS may create a unique opportunity to target these channels with therapeutic agents without producing unwanted off-target effects on normal neuronal physiology, and we speculate that targeting these ion channels may ameliorate cognitive deficits observed in PTHS and potentially schizophrenia.

 

 

Disordered breathing in a Pitt-Hopkins syndrome model involves Phox2b-expressing parafacial neurons and aberrant Nav1.8 expression

Pitt-Hopkins syndrome (PTHS) is a rare autism spectrum-like disorder characterized by intellectual disability, developmental delays, and breathing problems involving episodes of hyperventilation followed by apnea. PTHS is caused by functional haploinsufficiency of the gene encoding transcription factor 4 (Tcf4). Despite the severity of this disease, mechanisms contributing to PTHS behavioral abnormalities are not well understood. Here, we show that a Tcf4 truncation (Tcf4^tr/+) mouse model of PTHS exhibits breathing problems similar to PTHS patients. This behavioral deficit is associated with selective loss of putative expiratory parafacial neurons and compromised function of neurons in the retrotrapezoid nucleus that regulate breathing in response to tissue CO₂/H⁺. We also show that central Nav1.8 channels can be targeted pharmacologically to improve respiratory function at the cellular and behavioral levels in Tcf4^tr/+ mice, thus establishing Nav1.8 as a high priority target with therapeutic potential in PTHS. 

 

Repurposing Approved Drugs as Inhibitors of K_v7.1 and Na_v1.8 To Treat Pitt Hopkins Syndrome

Purpose:

Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder caused by mutations of a specific gene, transcription factor 4 (TCF4), located on chromosome 18. PTHS results in individuals that have moderate to severe intellectual disability, with most exhibiting psychomotor delay. PTHS also exhibits features of autistic spectrum disorders, which are characterized by the impaired ability to communicate and socialize. PTHS is comorbid with a higher prevalence of epileptic seizures which can be present from birth or which commonly develop in childhood. Attenuated or absent TCF4 expression results in increased translation of peripheral ion channels K_v7.1 and Na_v1.8 which triggers an increase in after-hyperpolarization and altered firing properties.

Methods:

We now describe a high throughput screen (HTS) of 1280 approved drugs and machine learning models developed from this data. The ion channels were expressed in either CHO (K_V7.1) or HEK293 (Na_v1.8) cells and the HTS used either ⁸⁶Rb⁺ efflux (K_V7.1) or a FLIPR assay (Na_v1.8).

Results:

The HTS delivered 55 inhibitors of K_v7.1 (4.2% hit rate) and 93 inhibitors of Na_v1.8 (7.2% hit rate) at a screening concentration of 10 μM. These datasets also enabled us to generate and validate Bayesian machine learning models for these ion channels. We also describe a structure activity relationship for several dihydropyridine compounds as inhibitors of Na_v1.8.

Conclusions:

This work could lead to the potential repurposing of nicardipine or other dihydropyridine calcium channel antagonists as potential treatments for PTHS acting via Na_v1.8, as there are currently no approved treatments for this rare disorder.

  

Repurposing the Dihydropyridine Calcium Channel Inhibitor Nicardipine as a Na_v1.8 inhibitor in vivo for Pitt Hopkins Syndrome

Individuals with the rare genetic disorder Pitt Hopkins Syndrome (PTHS) do not have sufficient expression of the transcription factor 4 (TCF4) which is located on chromosome 18. TCF4 is a basic helix-loop-helix E protein that is critical for the normal development of the nervous system and the brain in humans. PTHS patients lacking sufficient TCF4 frequently display gastrointestinal issues, intellectual disability and breathing problems. PTHS patients also commonly do not speak and display distinctive facial features and seizures. Recent research has proposed that decreased TCF4 expression can lead to the increased translation of the sodium channel Na_v1.8. This in turn results in increased after-hyperpolarization as well as altered firing properties. We have recently identified an FDA approved dihydropyridine calcium antagonist nicardipine used to treat angina, which inhibited Na_v1.8 through a drug repurposing screen.

 

All of the above was a parent driven process.  Well done, Audrey!

Questions remain.

Is Nicardipine actually beneficial to people with Pitt Hopkins Syndrome? Does it matter at what age therapy is started? What about the K_v7.1 inhibitor?

 

Conclusion 

Genetics is complicated, ion channel dysfunctions are complicated; but just a superficial understanding can take you a long way to understand autism, epilepsy and many other health issues.

There is a great deal in this blog about channelopathies/ion channel dysfunctions.

https://epiphanyasd.blogspot.com/search/label/Channelopathy

Almost everyone with autism has one or more channelopathies. Most channelopathies are potentially treatable.

Parents of children with rare single gene autisms should get organized and make sure there is basic research into their specific biological condition.  They need to ensure that there is an animal model created and it is then used to screen for existing drugs that may be therapeutic.  I think they also need to advocate for gene therapy to be developed.  This all takes years, but the sooner you start, the sooner you will make an impact.

Very likely, therapies developed for some single gene autisms will be applicable more broadly.  A good example may be the IGF-1 derivative Trofinetide, for girls with Rett Syndrome. IGF-1 (Insulin-like growth factor 1) is an important growth factor that is required for proper brain development. In the brain, IGF-1 is broken down into a protein fragment called glypromate (GPE). Trofinetide is an orally available version of GPE.

The MeCP2 protein controls the expression of several genes, such as Insulin-like Growth Factor 1 (IGF1), brain-derived neurotrophic factor (BDNF) and N-methyl-D-aspartate (NMDA).  All three are implicated in broader autism. 

https://rettsyndromenews.com/trofinetide-nnz-2566/

In girls with Rett Syndrome the genetic mutation is in the gene MeCP2, but one of the key DEGs (differentially expressed genes) is the FXYD1; it is over-expressed. IGF-1 supresses the activity of FXYD1 and hopefully so does Trofinetide.  Not so complicated, after all!

Medicine is often driven by the imperative to do no harm.

In otherwise severely impaired people, perhaps the imperative should be to try and do some good.

In medicine, time is of the essence; doctors in the ER can be heard to say "Stat!", from the Latin word for immediately, statim.  

How about some urgency in translating autism science into therapy? But then, what's the hurry? Why rock the boat?

On an individual basis, much is already possible, but you will have to do most of the work yourself - clearly a step too far for most people.