Advances in personalized medicine to treat Autism/IDD – Rett syndrome as an example. Also, Piperine to upregulate KCC2, but what about its direct effect on GABAa receptors?

 

Source:  https://www.cell.com/neuron/pdf/S0896-6273(21)00466-9.pdf

Today’s post is drawn from a workshop I am invited to present at an autism conference in Abu Dhabi.

I decided to talk about advances in personalized medicine – no surprise there.  Since I have 2 ½ hours, I thought I will need some interesting examples to maintain the audiences interest.  One such topic is going to be Rett syndrome.

I regard Rett syndrome and all the other such syndromes in this blog as “single gene autisms” (monogenic autism).  If you apply the American DSM classification, from 2013 onwards Rett syndrome is no longer part of autism.  Hopefully there are no such purists attending in Abu Dhabi. 

Two gene therapies for Rett syndrome are currently undergoing human trials and one drug therapy has been FDA approved.  This looks very encouraging, so let’s dig a little deeper.

Rett syndrome can present with a wide range of disability ranging from mild to severe. 

Rett syndrome is the second most common cause of severe intellectual disability after Down syndrome.

Other symptoms may include:

•      Loss of speech

•      Loss of purposeful use of hands

•      Loss of mobility or gait disturbances

•      Loss of muscle tone

•      Seizures or Rett “episodes”

•      Scoliosis

•      Breathing issues

•      Sleep disturbances

•      Slowed rate of growth for head, feet and hands

Here are the new therapies: 

TSHA-102: This gene therapy, developed by Taysha Therapeutics, is a gene replacement therapy that aims to deliver a functional copy of the MECP2 gene to brain cells.  It utilizes an AAV-9 virus to carry the miniMECP2 gene product into cells for the body to produce more MeCP2 protein, which is deficient in Rett syndrome. As of February 2024, Taysha completed dosing for the first cohort (low dose) in their REVEAL Phase 1/2 adolescent and adult trial in Canada, with positive interim data on safety. They are also conducting trials in the US for both pediatric and adolescent/adult populations.

NGN-401: This gene therapy, by Neurogene Inc., employs a different approach. It uses an AAV9 vector to deliver a regulated version of the MECP2 gene called EXACT. This technology aims to control the amount of MECP2 protein produced by the gene, mitigating the risk of overproduction. NGN-401 is currently in a Phase 1/2 trial for girls with Rett syndrome aged 4 to 10 years old.

Daybue (trofinetide)

Daybue is the first and only FDA-approved treatment specifically for Rett syndrome in adults and children two years of age and older. It is not a gene therapy, but rather a medication taken orally.

The optimistic AI generated view:

Here's a breakdown of Daybue for Rett syndrome:

• Mechanism: The exact way Daybue works in Rett syndrome isn't fully understood, but it's believed to target neuroinflammation and support synaptic function.
• Dosage: The recommended dose is based on the patient's weight and is taken twice daily, morning and evening, with or without food.
• Administration: Daybue comes as an oral solution and can be taken directly or through a gastrostomy tube if swallowing is difficult.
• Efficacy: Studies have shown that Daybue can improve symptoms of Rett syndrome, including reducing scores on the Rett Syndrome Behavior Questionnaire (RSBQ) and showing improvement on the Clinical Global Impression-Improvement (CGI-I) scale.
• Side Effects: The most common side effects of Daybue are diarrhea and vomiting. Weight loss can also occur in some patients. It's important to consult with a healthcare professional for monitoring and managing any potential side effects.

Daybue is an expensive medication. Here's what we know about the cost:

• List Price: The list price of Daybue is around $21.10 per milliliter.
• Annual Cost: This translates to an estimated average annual cost of around $375,000 for patients.
• Dosage Variability: It's important to note that the dosage of Daybue is based on a patient's weight, so the annual cost can vary depending on the individual.

Insurance and Assistance Programs:

• The high cost of Daybue highlights the importance of insurance coverage. Whether insurance covers Daybue and to what extent will depend on your specific plan.
• The manufacturer, Acadia Pharmaceuticals, offers a copay program called Daybue Acadia Connect. This program may help eligible commercially insured patients pay $0 for their monthly prescription.

What are the parents' groups saying? 

Not as good as you might be expecting for $375,000 a year.

Affordable potential alternatives to Daybue/Trofinetide

Daybue/Trofinetide is the product of decades of research into a growth factor called IGF-1.

It is a complicated subject and as usual the abbreviations can be confusing.

As you will see below there already is an OTC product commercialized by one of the original researchers, Dr Jian Guan.

One Rett syndrome parent, who reads this blog, has trialed cGP and sees a benefit. You rather wonder why the Phelan-McDermid, Pitt Hopkins, Angelman and Prader-Willi parents don’t follow him and splash out 50 USD and make a trial.

 

 

Gene-therapy

Gene therapy is undoubtedly very clever and ultimately will likely be the best therapy.  It still may not be that silver bullet.

To be effective gene therapy needs to be given at a very young age, ideally as a fetal therapy prior to birth. Note that we saw that in the Rett mouse model they gave bumetanide to the pregnant mother just before birth.

Fetal therapy is not a crazy idea and much is already written about it; many pregnancies are terminated because genetic anomalies are detected prior to birth. Down syndrome is the best-known example. Fetal therapy is realistic for some disorders.

Girls with Rett syndrome are often diagnosed first with idiopathic autism and then years later with a more precise diagnosis of Rett syndrome. This is a common experience among readers of this blog.

Classic Rett syndrome 

The average age of diagnosis for this form is around 2.5 years old in the US and 5 years old in the UK.  Why do you think that is?

Research in mouse models has shown that the effect of gene therapy ranges from curative when given extremely young to more limited the later it is given.

Off-target effects

Gene therapy has the potential for off-target effects. This is a significant concern in the field and researchers are actively working on ways to minimize these risks. Here is a breakdown of what off-target effects are and why they matter:

During gene therapy, a modified gene is delivered to target cells with the aim of correcting a genetic defect.

Ideally, the modified gene integrates into the intended location in the genome.

However, there's a chance it might insert itself into unintended locations (off-target sites).

Potential Consequences of Off-Target Effects

Disrupting normal genes at off-target sites could lead to unpredictable and potentially harmful consequences. This could include triggering uncontrolled cell growth, which is a risk factor for cancer.

It can also cause unexpected side effects depending on which genes are accidentally disrupted.

Minimizing Off-Target Effects

Researchers are developing various strategies to improve the accuracy and specificity of gene therapy techniques.

This includes using more precise gene editing tools like CRISPR-Cas9 with optimized guide RNAs to reduce off-target edits.

Additionally, researchers are working on methods to detect and potentially repair any off-target modifications that might occur.

Over-expression of the target gene

Yes, there is a possibility that the replaced gene in gene therapy could overproduce the expressed protein. This can be a potential complication and researchers are working on ways to control the level of protein expression. Here's a breakdown of the concern:

• Gene Dosing: Ideally, gene therapy aims to deliver a functional copy of the gene at the right amount to compensate for the deficiency.
• Overproduction Risks: However, if the delivered gene is too active or multiple copies are inserted, it can lead to overproduction of the protein.

Consequences of Protein Overproduction:

• Overproduction of a protein can disrupt the delicate balance in the cell, potentially leading to cell dysfunction or even cell death.
• In some cases, the protein itself might have harmful effects if present in excessive amounts.

Controlling Protein Expression:

Researchers are developing several strategies to control protein expression in gene therapy:

• Promoter selection: Using promoters that have a weaker switch can help regulate protein production.
• Viral vectors: Engineering viral vectors to control the number of gene copies delivered to cells.
• Inducible systems: Developing gene therapy methods where the expression of the introduced gene can be turned on and off as needed.

The cost of gene therapy

•      Despite the high cost, gene therapy can be a cost-effective treatment for some diseases. This is because it can eliminate the need for lifelong treatment with other medications.

•      Here are some examples of the cost of currently available pediatric gene therapies:

•      Luxturna (gene therapy for Leber congenital amaurosis type 10): $425,000

•      Zolgensma (gene therapy for spinal muscular atrophy type 1): $2.1 million

•      Skysona (gene therapy for adrenoleukodystrophy): $3 million

Piperine to correct KCC2 expression in Rett syndrome?

One key feature of Rett syndrome is impaired cognition.

As regular readers are aware, there are many types of treatable intellectual disability (ID).

One type of treatable ID is caused when the GABA developmental switch fails to occur shortly after birth.  This creates an excitatory/inhibitory imbalance in neurons which impairs cognition and lowers IQ.

The faulty GABA switch is a feature of many types of autism, but far from all of them.

By using pharmaceuticals to lower chloride within neurons, you can compensate for the failure of the GABA switch.

This treatment can be achieved by:

1.     Blocking or down regulating NKCC1

2.     Up regulating KCC2

In the paper below they look at up regulating KCC2

Pharmacological enhancement of KCC2 gene expression exerts therapeutic effects on human Rett syndrome neurons and Mecp2 mutant mice

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl CpG binding protein 2 (MECP2) gene. There are currently no approved treatments for RTT. The expression of K⁺/Cl⁻ cotransporter 2 (KCC2), a neuron-specific protein, has been found to be reduced in human RTT neurons and in RTT mouse models, suggesting that KCC2 might play a role in the pathophysiology of RTT.

Injection of KEEC KW-2449 or piperine in Mecp2 mutant mice ameliorated disease-associated respiratory and locomotion phenotypes. The small-molecule compounds described in our study may have therapeutic effects not only in RTT but also in other neurological disorders involving dysregulation of KCC2.

Thus, our data demonstrate that activation of the SIRT1 pathway or the TRPV1 channel enhances KCC2 expression in RTT human neurons.

Treatment with piperine (10 μM), an activator of the TRPV1 channel (51), induced a significant rise in KCC2 expression in cultured human neurons 

We already knew this was likely from earlier research from Ben Ari, see below for a reminder.  Is Piperine an interesting option for those restricted to OTC interventions?

Early alterations in a mouse model of Rett syndrome: the GABA developmental shift is abolished at birth

Genetic mutations of the Methyl-CpG-binding protein-2 (MECP2) gene underlie Rett syndrome (RTT). Developmental processes are often considered to be irrelevant in RTT pathogenesis but neuronal activity at birth has not been recorded. We report that the GABA developmental shift at birth is abolished in CA3 pyramidal neurons of Mecp2-/y mice and the glutamatergic/GABAergic postsynaptic currents (PSCs) ratio is increased. Two weeks later, GABA exerts strong excitatory actions, the glutamatergic/GABAergic PSCs ratio is enhanced, hyper-synchronized activity is present and metabotropic long-term depression (LTD) is impacted. One day before delivery, maternal administration of the NKCC1 chloride importer antagonist bumetanide restored these parameters but not respiratory or weight deficits, nor the onset of mortality. Results suggest that birth is a critical period in RTT with important alterations that can be attenuated by bumetanide raising the possibility of early treatment of the disorder.

One day before delivery, maternal administration of the NKCC1 chloride importer antagonist bumetanide restored these parameters but not respiratory or weight deficits, nor the onset of mortality. Results suggest that birth is a critical period in RTT with important alterations that can be attenuated by bumetanide raising the possibility of early treatment of the disorder.

Treating the mother prior to delivery with bumetanide was a partially effective therapy in the mouse model of Rett syndrome.

Piperine

Bumetanide is cheap and very possibly effective in human Rett syndrome, but it is a prescription drug.

Piperine is an OTC supplement and a compound found in black pepper. By activating the TRPV1 channel it causes an increase in expression of the KCC2 transporter that allows flow of chloride out of neurons. So piperine should lower chloride inside neurons.  Piperine can cross the blood brain barrier, so when taken orally it should have some effect on intracellular chloride.

Piperine is also a positive allosteric modulator of GABA_A receptors

This means that piperine multiplies the effect of whatever GABA is around. This means that in typical people piperine should have anti-anxiety effects.

Piperine was recently found to interact with a previously unknown  benzodiazepine-independent binding site.

Researchers are currently toying with the piperine molecule to try and separate the effect on TRPV1 from the effects on  GABA_A.  They want to create 2 new drugs.

1.     a selective TRPV1 activator

2.     a selective GABA_A modulator (PAM)

Piperine as an alternative or complement to Bumetanide?

One effect of piperine would be great to have (TRPV1 activator) but the second effect would not be helpful (positive allosteric modulator of GABAA).

The question is what is the net effect. Nobody will be able to answer that without a human trial.

I was advised long ago by one drug developer than it is best to focus on reducing flow into neurons via NKCC1, rather than increase its exit by KCC2, because nobody had yet been successful with KCC2; many have tried.  KCC2 plays a key role in neuropathic pain and that is why it has been researched.

Conclusion

We did see years ago that taking coffee with your bumetanide made sense. Coffee contains compounds that are OAT3 inhibitors and slow down the excretion of bumetanide from the body; coffee increases the effect of bumetanide. You can achieve something very similar by just increasing the dose of bumetanide.

Taking black pepper (piperine) with your bumetanide might be good, or might not be. It certainly would be easy to find out. As with Daybue/Trofinetide, the result is likely to vary from person to person. If GABA function, post- bumetanide, is still a bit excitatory amplifying GABA signaling will make autism worse. If GABA function has been shifted to inhibitory then amplifying GABA signaling will be calming.

Gene therapy will require much earlier diagnosis of single gene autisms.

“Precision medicine” therapies like Daybue/Trofinetide may not be that precise after all and large variations exist in the response, even among children with the same affected gene.

The huge expense means that for most of the world they will see no benefit from gene therapy or indeed “precision medicine.”

The low hanging fruit is to repurpose affordable existing drugs and get the benefit from their secondary effects.  This is what I term personalized medicine.

The research clearly indicates that some girls with Rett syndrome likely will benefit from Bumetanide therapy. For a young child this therapy would cost 50 US dollars/euros a year, if you pay the actual price for generics.

Why are they trialing genetic therapies for Rett instead of first doing the obvious thing and trialing cheap bumetanide? They will likely be able to sell the gene therapy for $2 million a shot.  There is little interest in trialing a $50 a year therapy.

Our new reader from Turkey, MÜCADELECI ANNE DENIZ ( = FIGHTING MOTHER DENIZ), likely does not have $2 million to spend, but seems to be on the way to creating her own personalized medicine therapy for her son. Good luck to her.

As to the cGP Max supplement, it seems to work for some and have no effect in others. Nobody has reported any side effects. It looks worth a try for Rett syndrome.  As a supplement it is not cheap, that is until you see what they charge for Daybue. 

Pentoxifylline and cGP (an IGF-1 normalizer) from Blackcurrants, for Autism?

 

 

Readers may be wondering at what point Peter will run out of things to write about.  I do sometimes wonder the same thing. I was going to also write about Loperamide (Imodium), but the post would have been too long. Next time!

Pentoxifylline

Pentoxifylline has been in use to treat autism for 50 years. The original studies did suggest its effect was greatest among small children.  I have been in some discussions with a US psychiatrist, Dr Powell, who is a big fan of the off-label use of this drug to affect the brain in adults.  He has even written a book on the subject.

My previous posts on Pentoxifylline can be found here: 

https://www.epiphanyasd.com/search/label/Pentoxifylline

Dr Powell’s patients with autism tend to be older children, not the toddlers who did well in clinical trials in Japan in the 1970s.  He sees significant improvement in many, but not all, of his patients with autism.  The parents report improved social interactions and having higher-level discussions with their child.

What is notable is that he uses frequent dosing, 4 times a day, always after food to avoid the GI side effects.

Pentoxifylline is inexpensive, but its effect does not last long, hence the frequent dosing.  Some people take taking this drug 5-6 times a day.

Pentoxifylline has multiple modes of action, it should increase blood flow to the brain and it is broadly anti-inflammatory.  It is a non-selective PDE inhibitor, normally used treat muscle pain in people with peripheral artery disease. It increases red blood cell flexibility and it reduces the viscosity of blood.

There are PDEs 1 to 11. It all gets quite complicated, for example PDE1 subtype A2 has a potential role in neurodegenerative diseases, including:

·        Parkinson's disease

·        Axonal neurofilament degradation

·        Motorneuronal degradation

·        Neuronal ischemia

·        Alzheimer's disease

·        Epilepsy

Recall that PDE4 inhibitors are used to treat asthma and COPD. We can potentially repurpose those to improve myelination in MS, or autism, and at specific low doses they can improve cognition.

 

cGP (from Black Currants)

I did write quite a lot in this blog about growth factors and autism.  The familiar ones are BDNF, NGF and IGF-1, but there are many more. 

My previous posts on IGF-1 can be found here: 

https://www.epiphanyasd.com/search/label/IGF-1

We know that growth signaling in autism is disturbed, but it is not simple.  As the disease progresses (the fetus develops, the baby is born and grows into a toddler) the imbalance in growth signaling changes.  This means that what would be helpful in a 6 month old baby might well be inappropriate in a 6 year old.  This is a good example of what I call the what, when and where of treating autism. Here it is the “when” that matters.

Some people lack BDNF while others have too much. Very possibly, this changes over time in the same child.

One possible therapy for autism is injections of IGF-1 (Insulin-like Growth Factor 1).  IGF-1 plays an important role in childhood growth.

A synthetic analog of IGF-1 is used in children for the treatment of growth failure.  This drug called Mecasermin was used in autism trials and in Rett syndrome trials.

In Rett syndrome the search has been on for an oral therapy.

Trofinetide (NNZ-2566) is a potential therapy for Rett syndrome being developed by Neuren Pharmaceuticals in Australia.

Trofinetide is derived from IGF-1.

Trofinetide got to phase 2 trials as a therapy for Fragile-X in 2015.

The second product in development at Neuren is NNZ-2591.  It is aimed at normalizing the level of IGF-1.

This is in the pipeline to treat:

• Phelan-McDermid syndrome (Shank3 gene and others not working)
• Angelman syndrome (UBE3A gene not working)
• Pitt Hopkins syndrome (TCF4 gene not working)
• Prader-Willi syndrome (MAGEL2 gene and others not working)

https://www.neurenpharma.com/irm/content/product-development-pipeline.aspx?RID=483&RedirectCount=1

 

What is NNZ-2591?

It is an analogue (modified version) of cyclic glycine proline (cGP)

Cyclic glycine-proline (cGP), a metabolite of IGF-1, is neuroprotective through improving IGF-1 function.

There is also research focused on Parkinson’s and Alzheimer’s where it seems that cGP is reduced.

In New Zealand they found that supplementation of Blackcurrant anthocyanins (pigments) increased cGP in the spinal fluid of patients with Parkinson’s.

This also led the way to the idea of increasing cGP as means of protecting the brain during aging. There is now a commercial OTC product in New Zealand to do just this.

Our reader Daniel, who has a daughter with Rett syndrome, is assessing the benefit of cGP, using the OTC product cGPMAX. The results so far are promising.

Rett is very specific because we know for sure that IGF-1 and NGF are disturbed.

Is cGP going to be beneficial in broader autism?  May be yes, but we come back to the what, when and where.  It may well depend on when a specific person takes it.  We have both hypoactive pro-growth signalling autism and hyperactive pro-growth signalling autism.

 

 

Unfortunately, what the clever researchers who came up with the above concept did not consider is that you may start out hyper in the womb and switch to hypo a few short years later.

  

Conclusion

Frequently dosed Pentoxifylline looks like a potentially interesting therapy for many with autism, including some with high IQ.  Take note our Aspie readers.

Daniel’s idea to look at the Neuren’s non-Rett therapy as a Rett therapy is interesting.  In effect you do not need to wait for the Australian drug, you can hop across the Tasman Sea to New Zealand and use their cGP supplement, developed for protection against dementia.

You would also think that parents of children with:

• Phelan-McDermid syndrome (Shank3 gene and others not working)
• Angelman syndrome (UBE3A) gene not working)
• Pitt Hopkins syndrome (TCF4 gene not working)
• Prader-Willi syndrome (MAGEL2 gene and others not working)

might want to follow Daniel’s lead.

As you can see, there is a lot of trial and error in science.  Back in 2009 NNZ-2566 was in clinical trials for the treatment of cognitive deficits following traumatic brain injury.  That must not have worked out.  Fragile-X did not work out and now it is phase 3 for Rett girls, which seems to be going well.

 

IGF-1 for old people

The same growth factor IGF-1 that is key during development also plays a key role in aging. Dr Jian Guan made a world first discovery. She discovered that cGP (cyclic Glycine-Proline) was responsible for controlling the IGF-1 hormone in our body. Thus by increasing the level of cGP in our body, the cGP will essentially command the IGF-1 to build more blood vessels.

Dr Jian Guan, was then recognised as the world-wide authority on cGP. In 2017 she discovered that New Zealand blackcurrants contained high volumes of natural cGP which could regulate optimum levels of IGF-1 in the body.

So now we have Antipodeans/Kiwis fending off dementia, and potentially metabolic syndrome, by taking their locally made cGPMax.

Will it help you case of autism? Who knows, but if it does not, just give the leftover pills to Grandma, Granddad or take them yourself!

 

All the supporting papers from New Zealand.

https://cgpmax.com/pages/our-science

 

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.