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Showing posts with label Rett Sydrome. Show all posts
Showing posts with label Rett Sydrome. Show all posts

Wednesday, 30 October 2019

More Research to support a Trial of Clemastine in Autism and particularly in Pitt Hopkins




                                                

Clemastine is an old antihistamine drug that we saw in earlier posts can stimulate oligodendrocytes to work harder and produce more myelin.

Myelin is needed to learn new skills and to control your body. It only starts to form in the third trimester, as the brain begins to grow rapidly. Myelination continues after birth but the rate appears to be controlled by social/emotional exposure.  The more isolated the baby is, the less myelin is produced.





                          









Interruption of the myelination process is known to cause long term problems.

Loss of myelin and lack of remyelination underlies Multiple Sclerosis.

It appears that loss of myelin may underlie cognitive loss in regressive autism, childhood disintegrative disorder and adult hypoxia.  First the myelin layer is lost and, depending on the underlying dysfunction, the neuron may die.  If it is just a case of lost myelin this can potentially be repaired.

Girls with Rett syndrome regress and lose previously acquired skills at about 18 months.  Is the loss of skills also a manifestation of a loss of myelin?  If so, can this loss of skills be controlled to minimize its effect?

In a previous post we have looked at the repurposing of Clemastine to improve remyelination.  At high doses this is an emerging therapy for Multiple Sclerosis (MS).  MS is a progressive disease where myelin is repeatedly lost.  Myelin is not permanent and constantly needs to be “remyelinated”.

As Ling has noted, the Pitt Hopkins syndrome researchers have published their results looking at mouse models of both Pitt Hopkins and broader autism and they have found that the same oligodendrocyte genes are indeed dysregulated in all these cases.
We already knew that myelin in idiopathic autism is thinner than it should be, which was why I was originally looking at ways to enhance myelination.

The new research gives further support for remyelination as a target for improving learning, cognitive function and motor skills in autism.  The new data shows that this likely particularly applies to those with Pitt Hopkins syndrome.  This syndrome is caused by a lack of Transcription Factor 4 (TCF4) when one of the two copies of its gene is not functional.  A more modest lack of TC4 is likely to be much more common that Pitt Hopkins itself.



Autism Spectrum Disorder (ASD) is genetically heterogeneous in nature with convergent symptomatology, suggesting dysregulation of common molecular pathways. We analyzed transcriptional changes in the brains of five independent mouse models of Pitt-Hopkins Syndrome (PTHS), a syndromic ASD caused by autosomal dominant mutation in TCF4, and identified considerable overlap in differentially expressed genes (DEGs). Gene and cell-type enrichment analyses of these DEGs highlighted oligodendrocyte dysregulation and we confirmed the myelin-associated transcriptional signature in two additional mouse models of syndromic ASD (Ptenm3m4/m3m4, Mecp2tm1.1Bird). We subsequently validated oligodendrocyte deficits in our Tcf4 mouse model which showed inefficient oligodendrocyte maturation in both an isolated oligodendrocyte in vitro cell culture system and ex vivo at day 24 (P24) and day 42 (P42). Furthermore, we used transmission electron microscopy (TEM) to visualize myelination in the corpus callosum (CC) of Tcf4+/tr and Tcf4+/+ littermates, observing a significant decrease in the proportion of myelinated axons in the CC of Tcf4+/tr mice compared to Tcf4+/+ littermates. Similar to our ex vivo IHC results, we observed a significant reduction in the number of CNP-positive oligodendrocytes in primary cultures derived from Tcf4+/tr mice compared to Tcf4+/+ littermates. When comparing compound action potentials (CAP) using electrophysiology, we show the ratio of N1/N2 is significantly reduced in the Tcf4+/tr mice compared to Tcf4+/+ littermates, indicative of a greater proportion of CAP traveling down unmyelinated axons. Moreover, we integrated syndromic PTHS mouse model DEGs with human ASD genes (SFARI) and human idiopathic ASD postmortem brain RNA-seq, and found significant enrichment of overlapping DEGs and common biological pathways associated with myelination. Remarkably, we show that DEGs from syndromic ASD mouse models can be used to identify human idiopathic ASD cases from controls. These results from seven independent mouse models of ASD are validated in human brain, implicating disruptions in oligodendrocyte biology as shared mechanisms in ASD pathology.


Here is more on the same paper:-



Genes involved in the formation of myelin, a fatty substance that sheathes neurons, are altered in brain tissue from autistic people and in several mouse models. The mice also have unusually few myelinated nerve fibers.
Researchers presented the unpublished findings yesterday at the 2019 Society for Neuroscience annual meeting in Chicago, Illinois.
“In general, across the whole spectrum, there’s a defect in myelination,” says Brady Maher, lead investigator at the Lieber Institute for Brain Development in Baltimore, Maryland.
Myelination is the process by which neuronal fibers are coated in myelin. Myelin is made by brain cells called oligodendrocytes, and it enables fast neuronal signaling.
Maher and his colleagues saw hints that myelination is disrupted in Pitt-Hopkins syndrome, an autism-related condition caused by mutations in a gene called TCF4. Children with this rare syndrome are slow to learn to walk, and most are minimally verbal; some have autism.
The researchers analyzed gene expression patterns in five mouse models of this syndrome, each with a different mutation in TCF4. They found that in all of the mice, genes involved in myelination are among those with altered expression.

The researchers then compared gene expression patterns of the mutant mice with those of two other autism mouse models: mice with mutations in MECP2 or PTEN. All three mouse models show alterations in the expression of a shared set of 34 genes, most of which are involved in myelination.
The same genes show atypical expression in two independent gene-expression datasets from autistic people, the researchers found.
Maher says his team is investigating why the TCF4 mutant mice have too few oligodendrocytes. They are also testing whether drugs that enhance myelination reverse the mice’s problems.

Clemastine in Autism

Several readers of this blog have reported a positive effect from Clemastine, you can find their comments in earlier posts.

Monty, aged 16 with ASD, has been using it for many months and it will be added to my Polypill at the next update.

In the US Clemastine is no longer available in the OTC form.  It is available as a generic with a prescription


In the rest of the world it is called Tavegil, or Tavegyl and being a common hay fever drug is usually OTC (no prescription).

In the Baltic states 20 tablets cost Eur 5 (USD 5.50). In the United Kingdom 60 tablets costs GBP 10 (USD 13).  You may have to ask the pharmacy to order it for you, it is not widely stocked, or order it online.

A 1 mg tablet of Clemastine contains 1.34 mg of Clemastine hydrogen fumarate.  This can be confusing because one product is marked 1mg and the identical tablet is elsewhere marked 1.34mg.

The US product by Teva is Clemastine 2mg containing 2.7 mg of Clemastine hydrogen fumarate

The experimental dose in Multiple Sclerosis is so high it causes drowsiness.  Clemastine affects histamine H1 receptors in the brain and so makes you sleepy.

My “autism dose” is less than the hay fever dose and is 1mg Clemastine (containing 1.34 mg of Clemastine hydrogen fumarate) taken in the evening.

Some readers are giving a morning dose and an evening dose, as you would for hay fever.  I would expect this to have a greater effect on oligodendrocytes, but will come at the cost of a degree of drowsiness, which may or may not be important.

I think people should be given clemastine immediately after a regression into autism and also anyone suffering as result of hypoxia. We saw the MRI of a man treated with clemastine after hypoxia in an earlier post and we saw the myelin damage and its repair.

Given 18 months of age is the typical age for the first regression in autism, perhaps pediatricians should take note? Perhaps the Johns Hopkins doctors should try using it on their patients with mitochondrial disorders?

I would also think those with what was called CDD (childhood disintegrative disorder) would be likely beneficiaries.

Comments so far suggest that clemastine benefits some people more than others, but this is exactly what you would expect.  In the case of the man with hypoxia, clemastine really was a silver bullet, it was given very promptly and loss of myelin was his only problem.  Most people with severe autism have more problems than just patchy myelin.


Treatment Window

In some single gene autism there does appear to be a treatment window and this has been confirmed in animal models. One example is the very expensive use of the drug Rapamycin in TSC (tuberous sclerosis complex).

Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain


Many interventions however do seem to be beneficial regardless of age.

This can be summed up as “it's never too late, but the sooner you start the better the result will be”.

Will a toddler with Pitt Hopkins learn to walk much earlier if taking Clemastine?  The logic is there to support this.

Will a girl with Rett Syndrome regress less far if taking Clemastine, during the regression?


Conclusion

Most parents naturally hesitate to give drugs to treat children with autism. They do not hesitate to give numerous drugs to their elderly relatives, who are the ones who are most likely to get side effects and have much less time to benefit from them.

Some drugs are much safer than others and the irony is that the drugs commonly used to treat autism by psychiatrists are the ones with known problems.

It appears that many very safe existing drugs can be used to treat features of autism.

Do you wait a decade, or likely more, to see if a safe old hay fever drug might improve cognition and/or motor skills in your case of autism or Pitt Hopkins? Or just buy these hay fever pills and see for yourself?

7 Previous posts on/including Clemastine:- 








Thursday, 23 November 2017

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


People keep telling me that my blog is too complicated; compared to the literature it really is not. If your child has a disabling condition you really should be willing to invest all the time needed to learn about it, rather than be a passive bystander.
I think you can investigate even complex sounding genetic disorders without being an expert, which is what happens in today’s post.  

Are there 20,000 types of jeans?

As readers may recall, humans only have about 20,000 genes, far less than originally was thought. Each gene provides the instructions to make one thing, usually a protein.
For the great majority of genes we have two copies, one from Mum and one from Dad. Mitochondrial genes all come from Mum.
These genes are stored on chromosomes (like recipe books).
For 22 of these recipe books you have two copies, so if one page got damaged at least you have an undamaged version from the other book.
The 23rd pair of books is special because while females have two copies, males do not. This is the X chromosome and if a male has a problem on any page in this little book, he has a big problem, while his sister has less of a problem, because she has a spare copy. The male has a Y chromosome in place of a second copy of X. 
Examples of problems on the X chromosome:-

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

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

Problems on chromosomes 1 to 22:-

If you have a problem in the first 22 chromosomes (recipe books), boys and girls are equal. If one page got damaged you can always look up the recipe in the other book.
In case one gene got mutated but the other copy is fine, things can work out just fine, in which case it is called haplosufficiency. You get to make enough of that protein.
In some cases you really need to use that recipe a lot; that particular protein is in big demand. One copy of that gene just is not enough. This is called  haploinsufficiency.
In most cases when the gene has a problem, it just fails to produce the intended protein. In some cases it actually produces a mutated protein, which can be worse than no protein. 

Pitt Hopkins

In Pitt Hopkins Syndrome there is a problem on chromosome 18, where you find the TCF4 gene. Not enough expression of TCF4 means not enough Transcription Factor 4;  this is an example of haploinsufficiency.
Now the reason why these rare conditions are important to many other people is that they not only affect people who happened to have a random mutation and hence a severe deficit of the protein; moderately reduced transcription of this gene, for any reason, can also result in troubling symptoms.
So in the case of the Pitt Hopkins and the gene TCF4, as was pointed out to me recently, reduced expression is a feature of some MR/ID and indeed schizophrenia. 


Instead of just a tiny number of people with Pitt Hopkins, you can see that upregulating TCF4 expression could help a lot of people.
It appears that people with Pitt Hopkins have a “clean copy” of TCF4, so it is just a case of making it work a little harder. There are ways being researched to achieve just that.
I suspect people with schizophrenia have two “clean copies” of TCF4, but for some reason have a deficiency of the protein encoded by it.
In the above paper it was shown that Protein Kinase A (PKA) plays a key role in regulating what your TCF4 gene is producing.
We have come across PKA before in this blog and we know that in regressive autism there can be a deficit of PKA. There is also PKB and PKC. All three are very important, but complicated. 


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

It all gets very complicated, but PKA is controlled by something called cAMP. In turn cAMP is controlled by PDE. PDE4 is known to be disturbed in the brains of some people with autism.
It appears that you can activate PKA with a PDE4 inhibitor. The long established Japanese asthma drug Ibudilast is such a PDE4 inhibitor. At least one reader of this blog uses Ibudilast long term.


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

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

I think I could keep that mouse quite busy. 
The point being you do not have to figure things out 100%, before starting to see what you have in your drug library might be truly beneficial.  
Some of the things in the drug library are actually in the kitchen cupboard, as we have already seen. 

Protein Kinase A
Protein kinase A (PKA) is something that is both complicated and important.
The effects of PKA activation vary with cell type.
PKA has always been considered important in formation of a memory.  Formation of a normal memory is highly sensitive to PKA levels; too much is bad and too little is bad.

ARID1B in Autism and Corpus Callosum Abnormalities
I don’t think anyone has set up a research foundation for agenesis of the Corpus Callosum (ACC), perhaps they should. 
There was a post on this a while back, prompted by meeting someone whose son has this condition. 

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

ACC is we are told a very rare condition, but clearly smaller corpus callosum variations are a key part of some autism. 
For example, in Pitt Hopkins a small corpus callosum is typical.
An estimated 7 percent of children with autism and macrocephaly (big heads) carry a PTEN mutation. This is associated with an enlarged corpus callosum. 
PTEN is an autism gene, but it is more usually thought of as a tumor suppressor, making it a cancer gene. In older people, losing PTEN appears to be often a first step to developing cancer; up to 70% of men with prostate cancer are estimated to have lost a copy of the PTEN gene at the time of diagnosis  (https://www.ncbi.nlm.nih.gov/pubmed/16079851). 

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


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

ARID1B gene
ARID1B is another tumor suppressing gene, like PTEN, and like PTEN it is also an autism gene.
What I found interesting was the link between ARID1B and corpus callosum anomalies. 

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



Corpus callosum abnormalities are common brain malformations with a wide clinical spectrum ranging from severe intellectual disability to normal cognitive function. The etiology is expected to be genetic in as much as 30–50% of the cases, but the underlying genetic cause remains unknown in the majority of cases.
Additional functional studies including a systematic search for ARID1B target genes may show how haploinsufficiency of ARID1B predispose to CC defects and to an array of cognitive defects, including severe speech defects

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


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

The full study:-


Clonazepam also reversed the reduced time spent in the center and reduced moving distance displayed by Arid1b-mutant mice in the open field test (Fig. 7c,d and Supplementary Fig. 14c). However, depression measures, using the forced swim test and the tail suspension test, showed no reversible effect of clonazepam in Arid1b+/− mice compared with controls (Fig. 7e,f). Our results show that clonazepam rescues impaired recognition, social memory, and elevated anxiety in Arid1b+/− mice. 
Our mouse model effectively mirrors the behavioral characteristics of intellectual disability and ASD. Arid1b+/− and Arid1bconditional-knockout mice displayed impaired spatial learning, recognition memory, and reference memory. Open field and social behavior tests also revealed decreased social interaction in the mice. Mice with mutations in genes encoding Smarca2 and Actl6b, other subunits of the BAF complex, have severe defects in social interaction and long-term memory35. Thus, this chromatin remodeling complex may provide a cellular and molecular platform for normal intellectual and social behavior. In addition, Arid1b+/− mice showed heightened levels of anxiety- and depression-related behaviors, which are common symptoms of ASD36. 
For people with intellectual disability, the prevalence of anxiety disorders has likewise been shown to be much higher. This may be due to reduced cognitive function and increased vulnerability to environmental demands. Communication difficulties may also make it more difficult for people with cognitive disabilities to deal with anxiety or fear. ARID1B haploinsufficiency may be responsible for multiple facets of characteristic ASD behaviors. Other isoforms of Arid1b that are not affected by the Arid1b mutation could exist in the mouse line. Additionally, it is possible that the genetic background for the mouse line may impact the effect of Arid1b haploinsufficiency. Thus it is important to consider allele specificity, genetic backgrounds, and knockout strategies for comparing phenotypes of other Arid1bhaploinsufficiency models.  
GABA allosteric modulators, including clonazepam, a benzodiazepine, have been used to treat seizures and anxiety. We found that clonazepam injection rescued deficits in object and social recognition and anxiety in Arid1b+/− mice. These results suggest that treatment with a benzodiazepine could be a potential pharmacological intervention for symptoms of ASD. Furthermore, our results suggest that pharmacological manipulation of GABA signaling is a potential treatment strategy for cognitive and social dysfunctions in ASD- or intellectual disability-associated disorders due to mutations in chromatin remodeling genes.  

ACC Research Foundation
If there actually was an ACC Research Foundation, they could explore whether clonazepam was therapeutic in children who have Arid1b haploinsufficiency.
While they are at it, they might want to look into Hereditary Motor and Sensory Neuropathy with agenesis of the corpus callosum (HMSN/ACC), this is caused by mutations in the potassium-chloride co-transporter 3 (SLC12A6/KCC3) gene. This I stumbled upon a long time ago, when trying to upregulate KCC2, which causes elevated intracellular chloride in many people with autism and likely many with Down Syndrome.

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

HMSN/ACC is a severe and progressive neurodegenerative disease that exhibits an early onset of symptoms. Signs of HMSN/ACC, such as hypotonia and delays in motor development skills, are noticed before 1 year of age. However, the motor abilities of patients progress slowly to 4–6 years of age, and these children are able to stand and walk with some help. This is followed by a motor deterioration that generally renders affected subjects wheelchair-dependent by adolescence. 
Accordingly, we found that curcumin relieved the ER retention of dimerized R207C in mammalian cultured cells. A diet enriched in curcumin may therefore be beneficial for the relief or delay of some of the HMSN/ACC symptoms in patients bearing the R207C mutation, including the Turkish patient described in this study (as patient has not yet reached puberty).

KCC3 defects also cause the very similar Andermann syndrome also known as agenesis of corpus callosum with neuronopathy (ACCPN).
KCC3 defects are associated with epilepsy.
My question was can you have KCC3 under-expression with partial ACC, epilepsy but no peripheral neuropathy? If this was likely, then upregulating KCC3 with curcumin might help.
The gene for KCC3 is located at chromosome 15q14. Based on my “logic of associations”, if you have ACC and epilepsy you should consider KCC3 under-expression.
I did suggest to my former classmate whose son has partial ACC and epilepsy, but no neuropathy, that it might be worth trying some curcumin. Since his son is already on anti-epileptic drugs (AEDs) my suggested effect to look for was improved cognitive function.
6 months later it does indeed, apparently, improve cognitive function.  Of course this does not establish that upregulating KCC3 had anything to do with it. It is nonetheless a nice story and another parent has realized that you can change things for the better, in spite of what neurology currently says. 
The question now is can you have both ARID1B under-expression and KCC3 under-expression, in which case you would add some clonazepam, based on the latest research. At this point you should of course go and talk to your neurologist, rather than read my blog and that was my recommendation. 


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

Conclusion

If you have a biological diagnosis you are one big step closer to finding a therapy. Even if you have a diagnosis like partial Agenesis of the Corpus Callosum (ACC), you can go one step further and ask why. You have a 50% chance of being able to find out a specific gene that is the cause. If you know with certainty which gene is the originator of the problem, you know a lot.  I think you are then two big steps closer to a therapy.
In the case of Rett Syndrome, a really good website is run by their research foundation (Rett Syndrome Research Trust). They look like they mean business. 


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