Relations Autism Spectrum Disorder to Genetic or Prenatal Environmental Causes

Autism Spectrum Disorder is a developmental disorder that effects communication and behavior. It is referred to as a spectrum, due to its wide variety of type and severity of symptoms. Prior to the DSM-V, developmental disorders that now fall into the current spectrum diagnosis were: Asperger’s, Autism, and Pervasive Development Disorder. Statistically, it is now calculated that 1 in 59 children fall within the Autistic Spectrum by the CDC (Centers for Disease Control). Research has found that there is a strong genetic link with ASD. Our Classroom text supports this finding, stating that researchers agree that autism stems from abnormal brain functioning, usually due to genetic or prenatal environmental causes. (Berk, L. E. (2018). Exploring lifespan development) There is something that is a combination of genetic and prenatal environment that has been linked to causing birth defects such as Neural Tube Defects, Spina Bifida, and anencephaly (all of which impact the formation of the brain and or spinal column) and that is a folate deficiency caused by MTHFR polymorphism, a gene mutation. MTHFR stands for methylenetetrahydrofolate reductase. MTHFR plays a key role in processing amino acids, enzymes that are the building blocks of protein. Although, Folate deficiency can occur during pregnancy by lack of appropriate nutrition or vitamin intake, MTHFR Polymorphism is unique in the fact that the gene mutation effects the way your body metabolizes folate from its food.

Folate is known as Vitamin B9, which is essential for human grown and development. B9 is needed for heathy nervous, digestive, and immune systems. MTHFR may lead to high levels of homocysteine, an amino acid attributed as a risk factor for heart disease, low levels of folate and other vitamins. Among those “Other Vitamins” are B6 and B12. B6 (Pyridoxine) is important for brain development, the nervous system, and immune system. B12 (cobalamin) is needed for red blood cell formation, cell metabolism, nerve function, and DNA. All these vitamins also play key roles in the Methylation Cycle. There are plenty of studies about the necessities of folate during pregnancy, but it often isn’t connected directly to MTHFR. Many websites and notable resources note that there are genetic factors that attribute to low folate levels and even in some cases mentions polymorphism, but it doesn’t specifically state exactly which polymorphism. The Study by Anne Molly et al. goes into more detail on the importance of the roles Vitamins B12,B6, and B9 play: The metabolism of folic acid and vitamin B12 is closely intertwined. A deficiency of one of these vitamins alters the metabolism of the other. Low plasma vitamin B12 concentrations and low intakes of the vitamin are additional risk factors for NTD and homocysteinemia. Molloy, A. M., Kirke, P. N., Brody, L. C., Scott, J. M., & Mills, J. L. (2008) Hyperhomocysteinemia is seen commonly in individuals with deficiencies of folate, Vitamin B 12, or Vitamin B6, due to low intake and/or poor absorption of these vitamins from food, infections such as Helicobacter pylori and bacterial overgrowth, and/or genetic tendency towards these deficiencies.

Recently associations have been observed between abnormally high plasma homocysteine concentrations and abnormal pregnancy outcomes. A Retrospective study in the Netherlands reported that women in the highest quartile of plasma homocysteine were at increased risk for many birth defects and stillbirths, compared with those in the lower quartile. Molloy, A. M., Kirke, P. N., Brody, L. C., Scott, J. M., & Mills, J. L. (2008) One of those Genetic tendency towards these deficiencies stated by Molloy, A. M. et al could be very well considered the MTHFR gene mutation. Seeing how folate deficiency can affect the formation of the brain and spinal column, it is not a far jump to link it to the possibility as a contributing factor of a genetic predisposition to Autism. A deficit in B6,B9, and B12 during pregnancy, due to a genetic gene mutation such as MTHFR, could very well impact the formation of the brain and its functioning. There are various forms of MTHFR gene mutations and those mutations can be heterozygous (meaning one gene inherited from one parent) or Homozygous (having two genes, one from each parent). The Specific Mutation that has been linked to correlate with Autism in studies has been C677T (Heterozygous) and 677TT (Homozygous). Recent studies have shown a direct correspondence to ASD and MTHFR Gene mutations.

Below are three statements, taken directly from academic citations that that support the connection between ASD and the MTHFR Gene Mutation. We observed a significantly increased frequency of the homozygous mutation 677CT allele (TT): 23% in the autistic children compared to 11% in the control population (The differentially methylated regions (DMRs) were found to be highly biased towards autism related genes and CpG islands. This may imply a major mechanism for etiology of sporadic cases of autism: autism causing environmental factors serves as modulator to regulate a MTHFR -mediated epigenomics to regulate specific autism related gene. Liu, X. (2013) MTHFR C677T is a risk factor, whereas MTRR A66G and SHMT C1420T polymorphisms reduce risk for autism. MTHFR A1298C acts additively in increasing the risk for autism. Mohammad, N. S., Jain, J. M., Chintakindi, K. P., Singh, R. P., Naik, U., & Akella, R. R. (2009). All these studies, so far, touch base upon the MTHFR Gene mutation in Autistic Spectrum children and the studies regarding folate deficits of the mother, but none of the articles I have read regarding Autism spectrum disorders and MTHFR have touched base upon possible male contribution factors with MTHFR. This may need to be something more looked in upon because there are studies that link MTHFR with Male infertility.

Arguably, if folate is related to DNA formation, it could be possible that a folate deficit can affect the male contribution of DNA within the formation of a fetus. The New York Times published an Article on Jan. 1st, 1991 about research on birth defects shifting to flaws within the sperm. Researchers have found several childhood cancers that primarily arise from new mutations traced to sperm, never to eggs. They believe defects may originate during the division of the cells that generate sperm cells. Cells are most vulnerable to genetic damage when they divide because they are more likely to absorb and metabolize toxic substances than are quiescent cells. Eggs do not divide; all eggs a woman has are present before birth. By contrast, next to the cells in developing fetus the stem cells that produce sperm are among the most rapidly dividing cells in the human body. Moreover, researchers now realize that the barrier between blood vessels and tissue in the testes is very thin, allowing many toxic substances to enter testicular structures and seminal fluid. Animal studies have identified more than 100 chemicals that produce spontaneous abortion or birth defects in offspring fathered by exposed males, said Dr. Mattison.

Among them are alcohol, opiates like heroin and methadone, gases used in hospital operating rooms, lead, solvents, pesticides and a variety of industrial chemicals. In some instances, litter size is greatly reduced, or the offspring are deformed. In other cases, the young animals appear healthy but cannot negotiate mazes as well as control animals. One case pending before the United States Supreme Court involves restrictive work rules intended to protect women of childbearing age from exposure to lead, which can cause neurological defects. But in one recent study, Dr. Ellen Silbergeld, a toxicologist at the University of Maryland in Baltimore, exposed male rats to relatively low levels of lead, equivalent to amounts encountered by many factory workers. The male rats’ offspring showed defects in brain development, even if the female rats were not exposed to lead at all, Dr. Silbergeld said. Blakeslee, S. (1991, January 1). This article, although not talking about the topic of MTHFR, touches base upon human development and how male exposure to chemicals and toxicity can contribute to neurological deficits in children they father.

Sadly, just as this was an issue back in 1991, there is still more of a focus on the mother versus the father when it comes to genetic contribution in regards fetal development. Where there have been links to MTHFR causing infertility in men, and the B vitamins playing an essential role in the formation of DNA, I think there could be a possibility of this deficit playing a role in developmental issues within children as well. Possible corroboration of this is the Genetic 677T MTHFR link to autism, which means it is Homozygous, both parents being a contributor. MTHFR may in fact be the marker for helping to identify who can have autism, if a child has this, but I feel it’s the marker more about the parents and their vitamin deficiencies that can impact fetal development. I became aware of the MTHFR Gene Mutation after a long struggle with medication management with my eldest autistic spectrum son. He did not react well to Antidepressants , Antipsychotics, or Anxiolytics. It was brought to our awareness that there was a new test out there that could detect how your body metabolized certain medications. This test detected the MTHFR, which does affect how you metabolize not only foods, but also medications. I knew my mother, who had extensive mental illness, could not take most of medications that are supposed to control her condition and that there was more than likely something genetically going on. Both my Son and I got the Genetic testing done. My Son was Heterozygous, MTHFR C677T and I tested Homozygous 677TT. I have four children, two on the autistic spectrum, the other two have ADHD. I was diagnosed with PDD-NOS (Which would now just fall under the term of ASD) when I was 33 years old, after a therapist saw what she thought was Adult ADHD. I am 42 now. After the Genetic test and after researching what the MTHFR gene mutation does combined with medical issues I had been having, I asked for bloodwork to be conducted. I specifically wanted my B and D levels investigated because both deficits had the symptomology of what I was currently suffering medically. Turns out I was severely B12 and D deficient, as well as borderline anemic with B12 Deficient Anemia. I had no knowledge of my genetic issues nor that I was deficient in nutrients because of them during all my pregnancies. My family has a lot of learning disabilities on my father’s side and mental health issues on my mother side, both of which also happens to have the MTHFR gene mutation. I also found out my Grandmothers on both sides had to have b12 injections during their lifetime due to severe vitamin deficiency. Because of the prevalence of ASD in my family, combined with the new awareness and knowledge of the MTHFR Gene mutation and vitamin deficiencies that also run in the family, I do feel that there is a great possibility for the connection of the MTHFR Gene mutation and Autism.

However, I do not think the Gene mutation alone is the sole contributor. I think the MTHFR Gene mutation effects how we metabolize our food and depending on the degree and severity of the mutation, effects the severity of our vitamin deficiencies. Those deficiencies can impact the development of a fetus.

Research does support the necessity of Folate in fetal development.

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