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.

eIF4E inhibitors for Autism – Why not Ribavirin?

Some people find this blog too complicated and would prefer it to be simplified; it would be great if all the science could be accurately described in very simple terms.

This blog has ended up going into far more detail than I had ever intended, because if you want to get to the bottom of a problem you have to keep digging until you get to what is relevant.  The relevant part is not near the surface, as you will see in today’s post, but many potential therapeutic options are sitting there in plain view, obscured only by the scientific jargon.

eIF4E, ADNP, Alzheimer’s, Tauopathy and Autism

In today’s post I am drawing together material from autism, Alzheimer’s and other so-called tauopathies.  The post ends up with the suggestion that an existing antiviral drug called Ribavirin, which affects a very specific part of mTOR signaling, could be a useful autism therapy and should be the subject of a serious clinical trial.

Tauopathies sound interesting.  Tau protein is present in the brains of all humans, but it can dysfunction (hyperphosphorylation) and form tangles. When tau behaves like this it leads to so-called tauopathies, like Alzheimer’s.  Tangles form inside dying cells; they are twisted fibers of a protein tau. In areas where tangles are forming, the twisted strands of tau block nutrients from moving through the cells, causing cell death.

Most people develop some amyloid plaques and tau tangles as they get older, but people with Alzheimer’s tend to develop far more. Plaques and tangles tend to form in a pattern, starting in areas related to learning and memory and then spreading to other regions of the brain.

The question is to what extent are infantile tauopathies present in autism?  Particularly autism with MR/ID?

Tuberous Sclerosis (TSC) is a widely used research model of autism. TSC is a genetic disorder that is usually caused by the TSC2 gene, but can be caused by TSC1. TSC1 and TSC2 are growth supressors and dysfunction leads to the growth of benign tumors.  TSC is associated with seizures, autism, MR/ID and other issues.   TSC is a tauopathy.

It is unkown to what extent tauopathy may be present in autism, or those with mental retardation/intellectual disability. This question was also posed in the blog written by Dr Emily Casanova, wife of the neurologist/blogger Dr Manuel Casanova; the latter normally seems to get the most media attention.

A very expensive drug called Everolimus, is being used to treat TSC. Everolimus is a potent mTOR inhibitor. mTOR is part of a key constellation of signaling pathways implicated in cancer and autism. mTOR is extremely complex and even highly intelligent people will need quite some time to figure it out.  

  

Eukaryotic translation initiation factor 4E (eIF4E) 

Eukaryotic translation initiation factor 4E (eIF4E), is a protein that in humans is encoded by the EIF4E gene. 

 eIF4E seems to play a critical role in the mTOR pathway to trigger the excitatory/inhibitory imbalance in autism.

There are multiple pathways involved in this process and we previously looked at RORa.

The Purkinje-RORa-Estradiol-Neuroligin-KCC2 axis in Autism

We have already seen that in most autism the mTOR pathway is over active.  The problem is that this pathway is highly complex and affects very many aspects of your body.  You would ideally intervene in a highly selective manner.

eIF4E is just one small part of the mTOR pathway and it appears that by selectively inhibiting it, good things should happen.

In the chart below we would inhibit eIF4E (green box) and then expect a reduction in neuroligins (NLGNS), leading to more inhibition on neurons, resulting in better cognition and milder autism.

Over expression of eIF4E in mice leads to autistic behaviors.

Inhibition of eIF4E works in a mouse model of autism.

Inhibitors of eIF4E exist today.

ADNP

Activity-dependent neuroprotective protein (ADNP) is the most frequent autism associated gene and the only protein significantly decrease in the serum of Alzheimer's disease patients.

Israeli researchers investigating Alzheimer’s and otherTauopathies identified binding sites on ADNP for eIF4E.

ADNP expression is suggested as a master regulator of key ASD and AD risk genes.

It is also suggested, based on mouse research, that ADNP expression may contribute to the male/female variations in autism and Alzheimer’s (women are more affected by Alzheimer’s, but less by autism).  Increased male ADNP expression was replicated in human postmortem hippocampal samples.

Choice of of eIF4E Inhibitor

Thanks to all the cancer research there is detailed knowledge of eIF4E inhibitors.

As usual a key issue is bioavailability.

I thought ribavirin looks very interesting and I am not the only one (see later studies).  It is an old generic anti-viral medication, often used to treat hepatitis C. An expensive version is being developed as a cancer therapy.

Conclusion

All the evidence points towards eIF4E Inhibitors, but as the professionals would tell us, more research and validation is required. A clinical trial of Ribavirin would seem in order. 

There may be different types of E/I imbalance in autism and different therapies are likely to suit different people. 

The supporting science :-

Translating autism

Researchers at McGill University have mouse data showing a causal link between eIF4E-mediated translational dysregulation and autism-related deficits. The group also corrected the dysregulation—and the associated autistic phenotype—with a small molecule.¹

The McGill group, led by Nahum Sonenberg, has been studying the role of eukaryotic translation initiation factor 4E (eIF4E) in protein synthesis for over three decades and has primarily focused on the factor's relevance in cancer. eIF4E binds to the cap structure on mRNA and helps to initiate the translation of the mRNA. Sonenberg is a professor in the Department of Biochemistry and at the Rosalind and Morris Goodman Cancer Research Centre at McGill.

The team previously reported that eIF4E-mediated protein translation is modulated by the phosphoinositide 3-kinase (PI3K), protein kinase B (PKB; PKBA; AKT; AKT1) and mammalian target of rapamycin (mTOR; FRAP; RAFT1) pathway, which is commonly disrupted in cancer.²

He said the initial connection to autism came after other research groups showed that autistic children carry mutations in genes upstream of mTOR. These genes included PTEN (MMAC1; TEP1) and tuberous sclerosis complex tumor suppressor 1 (TSC1).^{3, 4, 5}

Separately, a 2009 study from a research group in the U.K. showed an association between mutations that increased eIF4E promoter activity and autism.⁶

With multiple studies pointing to eIF4E-dependent processes in autism, the McGill group sought to determine whether dysregulation of eIF4E activity itself could cause an autistic phenotype. Indeed, past studies suggested that dysregulated translation of mRNA could be an underlying cause of autism⁷ but never showed a causal relationship.

In a new study published in Nature, the McGill researchers showed that increasing eif4e activity in mice—by knocking out the gene encoding an eif4e repressor called eif4e binding protein 2 (eif4ebp2)—led to autism-associated electrophysiological abnormalities and behaviors.

In these mice, as well as mice that overexpressed eif4e, translation of neuroligin proteins was greater than that seen in wild-type controls. Alterations in neuroligin signaling occur in autism.^{8, 9}

In the mouse models, a small molecule inhibitor of eIF4E signaling called 4EGI-1 reversed the electrophysiological abnormalities and decreased autistic behaviors compared with vehicle. Knockdown of neuroligin 1 (Nlgn1) had similar effects.

Importantly, inhibition of eif4e and Nlgn1 activity did not affect electrophysiological and behavioral parameters in wild-type mice.

Autism-related deficits via dysregulated eIF4E-dependent translational control

Reversing autism by targeting downstream mTOR signaling

 Autism spectrum disorders (ASDs) are a group of clinically and genetically heterogeneous neurodevelopmental disorders characterized by impaired social interactions, repetitive behaviors and restricted interests. The genetic defects in ASDs may interfere with synaptic protein synthesis. Synaptic dysfunction caused by aberrant protein synthesis is a key pathogenic mechanism for ASDs Understanding the details about aberrant synaptic protein synthesis is important to formulate potential treatment for ASDs. The mammalian target of the Rapamycin (mTOR) pathway plays central roles in synaptic protein. Recently, Gkogkas and colleagues published exciting data on the role of downstream mTOR pathway in autism

Previous studies have indicated that upstream mTOR signaling is linked to ASDs. Mutations in tuberous sclerosis complex (TSC) 1/TSC2, neurofibromatosis 1 (NF1), and Phosphatase and tensin homolog (PTEN) lead to syndromic ASD with tuberous sclerosis, neurofibromatosis, or macrocephaly, respectively. TSC1/TSC2, NF1, and PTEN act as negative regulators of mTOR complex 1 (mTORC1), which is activated by phosphoinositide-3 kinase (PI3K) pathway. Activation of cap-dependent translation is a principal downstream mechanism of mTORC1. The eIF4E recognizes the 5′ mRNA cap, recruits eIF4G and the small ribosomal subunit. The eIF4E-binding proteins (4E-BPs) bind to eIF4E and inhibit translation initiation. Phosphorylation of 4E-BPs by mTORC1 promotes eIF4E release and initiates cap-dependent translation. A hyperactivated mTORC1–eIF4E pathway is linked to impaired synaptic plasticity in fragile X syndrome, an autistic disorder caused by lack of fragile X mental retardation protein (FMRP) due to mutation of the FMR1 gene, suggesting that downstream mTOR signaling might be causally linked to ASDs. Notably, one pioneering study has identified a mutation in the EIF4E promoter in autism families, implying that deregulation of downstream mTOR signaling (eIF4E) could be a novel mechanism for ASDs.As an eIF4E repressor downstream of mTOR, 4E-BP2 has important roles in synaptic plasticity, learning and memory. Writing in their Nature article, Gkogkas and colleagues reported that deletion of the gene encoding 4E-BP2 (Eif4ebp2) leads to autistic-like behaviors in mice. Pharmacological inhibition of eIF4E rectifies social behavior deficits in Eif4ebp2 knockout mice. Their study in mouse models has provided direct evidence for the causal link between dysregulated eIF4E and the development of ASDs.Are these ASD-like phenotypes of the Eif4ebp2 knockout mice caused by altered translation of a subset mRNAs due to the release of eIF4E? To test this, Gkogkas et al. measured translation initiation rates and protein levels of candidate genes known to be associated with ASDs in hippocampi from Eif4ebp2 knockout and eIF4E-overexpressing mice. They found that the translation of neuroligin (NLGN) mRNAs is enhanced in both lines of transgenic mice. Removal of 4E-BP2 or overexpression of eIF4E increases protein amounts of NLGNs in the hippocampus, whereas mRNA levels are not affected, thus excluding transcriptional effect. In contrast, the authors did not observe any changes in the translation of mRNAs coding for other synaptic scaffolding proteins. Interestingly, treatment of Eif4ebp2 knockout mice with selective eIF4E inhibitor reduces NLGN protein levels to wild-type levels. These data thus indicate that relief of translational suppression by loss of 4E-BP2 or by the overexpression of eIF4E selectively enhances the NLGN synthesis. However, it cannot be ruled out that other proteins (synaptic or non-synaptic) may be affected and contribute to animal autistic phenotypes.Aberrant information processing due to altered ratio of synaptic excitation to inhibition (E/I) may contribute to ASDs. The increased or decreased E/I ratio has been observed in ASD animal models  In relation to these E/I shifts, Gkogkas et al then examined the synaptic transmission in hippocampal slices of Eif4ebp2 knockout mice. They found that 4E-BP2 de-repression results in an increased E/I ratio, which can be explained by the increase of vesicular glutamate transporter and spine density in hippocampal pyramidal neurons. As expected, application of eIF4E inhibitor restores the E/I balanceFinally, in view of the facts that genetic manipulation of NLGNs results in ASD-like phenotypes with altered E/I balance in mouse models  and NLGN mRNA translation is enhanced concomitant with increased E/I ratio in Eif4ebp2 knockout mice, Gkogkas et al. tested the effect of NLGN knockdown on synaptic plasticity and behaviour in these mice . NLGN1 is predominantly postsynaptic at excitatory synapses and promotes excitatory synaptic transmission. The authors found that NLGN1 knockdown reverses changes at excitatory synapses and partially rescues the social interaction deficits in Eif4ebp2 knockout mice. These findings thus established a strong link between eIF4E-dependent translational control of NLGNs, E/I balance and the development of ASD-like animal behaviors (Figure 1).
In summary, Gkogkas et al. have provided a model for mTORC1/eIF4E-dependent autism-like phenotypes due to dysregulated translational control (Gkogkas et al., 2013). This novel regulatory mechanism will prompt investigation of downstream mTOR signaling in ASDs, as well as expand our knowledge of how mTOR functions in human learning and cognition. It may narrow down therapeutic targets for autism since targeting downstream mTOR signaling reverses autism. Pharmacological manipulation of downstream effectors of mTOR (eIF4E, 4E-BP2, and NLGNs) may eventually provide therapeutic benefits for patients with ASDs.

Targeting translation: eIF4E as an emerging anticancer drug target

Ribavirin Inhibitsthe Activity of mTOR/eIF4E, ERK/Mnk1/eIF4E Signaling Pathway and Synergizeswith Tyrosine Kinase Inhibitor Imatinib to Impair Bcr-Abl MediatedProliferation and Apoptosis in Ph+ Leukemia

Common EIF4E variants modulate risk for autism spectrum disorders in the high-functioning range

Deregulation of EIF4E: a novel mechanism for autism

1. Dr Z Miedzybrodzka, University of Aberdeen, Department of Genetics, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK; zosia@abdn.ac.uk

Abstract

Background: Autism is a common childhood onset neurodevelopmental disorder, characterised by severe and sustained impairment of social interaction and social communication, as well as a notably restricted repertoire of activities and interests. Its aetiology is multifactorial with a strong genetic basis. EIF4E is the rate limiting component of eukaryotic translation initiation, and plays a key role in learning and memory through its control of translation within the synapse. EIF4E mediated translation is the final common process modulated by the mammalian target of rapamycin (mTOR), PTEN and fragile X mental retardation protein (FMRP) pathways, which are implicated in autism. Linkage of autism to the EIF4E region on chromosome 4q has been found in genome wide linkage studies.

Methods and results: The authors present evidence that directly implicates EIF4E in autism. In a boy with classic autism, the authors observed a de novo chromosome translocation between 4q and 5q and mapped the breakpoint site to within a proposed alternative transcript of EIF4E. They then screened 120 autism families for mutations and found two unrelated families where in each case both autistic siblings and one of the parents harboured the same single nucleotide insertion at position −25 in the basal element of the EIF4E promoter. Electrophoretic mobility shift assays and reporter gene studies show that this mutation enhances binding of a nuclear factor and EIF4E promoter activity.

Conclusions: These observations implicate EIF4E, and more specifically control of EIF4E activity, directly in autism. The findings raise the exciting possibility that pharmacological manipulation of EIF4E may provide therapeutic benefit for those with autism caused by disturbance of the converging pathways controlling EIF4E activity.

Activity-dependent neuroprotective protein (ADNP)exhibits striking sexual dichotomy impacting on autistic and Alzheimer’s pathologies

  

Abstract

Activity-dependent neuroprotective protein (ADNP) is a most frequent autism spectrum disorder (ASD)-associated gene and the only protein significantly decreasing in the serum of Alzheimer's disease (AD) patients. Is ADNP associated with ASD being more prevalent in boys and AD more prevalent in women? Our results revealed sex-related learning/memory differences in mice, reflecting hippocampal expression changes in ADNP and ADNP-controlled AD/ASD risk genes. Hippocampal ADNP transcript content was doubled in male vs female mice, with females showing equal expression to ADNP haploinsufficient (ADNP^+/−) males and no significant genotype-associated reduction. Increased male ADNP expression was replicated in human postmortem hippocampal samples. The hippocampal transcript for apolipoprotein E (the major risk gene for AD) was doubled in female mice compared with males, and further doubled in the ADNP^+/− females, contrasting a decrease in ADNP^+/− males. Previously, overexpression of the eukaryotic translation initiation factor 4E (eIF4E) led to ASD-like phenotype in mice. Here, we identified binding sites on ADNP for eIF4E and co-immunoprecipitation. Furthermore, hippocampal eIF4E expression was specifically increased in young ADNP^+/− male mice. Behaviorally, ADNP^+/− male mice exhibited deficiencies in object recognition and social memory compared with ADNP^+/+ mice, while ADNP^+/− females were partially spared. Contrasting males, which preferred novel over familiar mice, ADNP^+/+ females showed no preference to novel mice and ADNP^+/− females did not prefer mice over object. ADNP expression, positioned as a master regulator of key ASD and AD risk genes, introduces a novel concept of hippocampal gene-regulated sexual dimorphism and an ADNP^+/− animal model for translational psychiatry.