Autism Spectrum Disorder: How MTHFR Affects Your Autistic Child

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects how people interact with other people, particularly in terms of your child's behavior and communication. Autism is known as a “spectrum” disorder because symptoms vary significantly between different people. Characteristics of autism spectrum disorder¹ are usually first noticed when children are very young; however, autism can be diagnosed at any age. 

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the autism spectrum disorder definition includes:

• Difficulty communicating and interacting with other people

• Restricted interests and repetitive behaviors

• Difficulty functioning “normally” at school, work, and other areas of life

Those who are able to function normally but struggle with social interaction may be described as having “high-functioning autism spectrum disorder,” although this is not a medically diagnosed condition. Autism spectrum disorder level 1 is described as the “highest functioning” form of autism, while level 3 is the most severe.

ASD is a developmental disability that may include stereotyped and repetitive motor mannerisms, limited communication, and impaired social skills. While the exact causes of autism are not certain, recent research has suggested that genetic conditions (such as Down syndrome or Fragile X syndrome) and environmental factors may play a part.

One particular study has noted that the genes involved in the folate/homocysteine pathway may increase the risk of autism in children and older parents, particularly the C677T polymorphism in the MTHFR gene.

The cerebral folate receptor alpha (FRα) is responsible for transporting 5-methyltetrahydrofolate (5-MTHF) into the brain. Low levels of 5-MTHF in the brain result in impaired transport of folates across the blood-brain barrier, which has been shown to result in cerebral folate deficiency (CFD). CFD has been associated with autism.²

It has been suggested that epigenetic modifications of the genes involved in normal brain development, growth, cognitive function, and behavior may play a part in the causes of autism.⁴ Epigenetic mechanisms are molecular events that govern the way the environment regulates the genomes of organisms, leading to individual differences in appearance, physiology, cognition, and behavior from one generation to the next.

There is already substantial evidence that DNA methylation defects are associated with autism spectrum disorders. This may be due to the MTHFR gene, which is responsible for folate metabolism. The MTHFR enzyme is one of the most important enzymes in the folate pathway. A mutation on the MTHFR gene impairs folate metabolism, potentially affecting epigenetic mechanisms. It is thought that this may modify complex gene expression, resulting in some autism symptoms.⁵

Folate metabolism plays a major role in the environmental risk factors of neurodevelopmental disorders such as autism. Individuals with the 677T MTHFR alleles are shown to have insufficient MTHFR activity, low plasma folate, and DNA hypomethylation.⁶ Children with autism spectrum disorder have been found to have higher levels of homocysteine.⁷

A 2009 study found that the MTHFR C677T polymorphism was more prevalent in autistic children than in non-autistic children (16.3 vs. 6.5%). The study concluded that both MTHFR C677T and MTHFR A1298C may increase the risk for autism.

A 2014 study also found that C677T appeared more often in autistic children than in non-autistic children (29% versus 24%), but this was not statistically significant. However, the researchers noted that other MTHFR polymorphisms, such as A1298C, may contribute to autism.⁸.

According to the Centers for Disease Control, autism affects an estimated 1 in 36 children and 1 in 45 adults in the United States today.

More recently, a 2021 study found that the MTHFR C677T polymorphism was significantly associated with the risk of autism in the Chinese Han population and that autistic children were more likely to be of low body weight.⁹

Finding out whether your child is affected by an MTHFR mutation may help you optimize their health and prevent significant health issues.

Symptoms of MTHFR Mutations

Most parents start with their pediatrician or child's health care provider, who is checking on developmental milestones. If your child is under the age of 3 years, you might be able to obtain an evaluation or autism diagnosis through your local early intervention system.

Testing methods for identifying an MTHFR mutation include saliva tests and/or a DNA panel test (which may include a mouth swab, hair sample, or a blood test).

Each method varies significantly in terms of cost and the amount of information that can be obtained about your genetics.

A genetic blood test (ordered by your doctor) is the most affordable option. Other options, such as DNA panel tests, must be sourced by you personally and often have a much higher cost.

If it turns out that your child has an MTHFR genetic mutation, don't panic. With the right diet and lifestyle, it's entirely possible to avoid or at least minimize health issues associated with MTHFR.

Processed foods should be off-limits for all children! These often contain added salts, sugars, fats, and artificial ingredients. Children who eat a lot of processed foods are shown to have poorer mental health conditions and weaker locomotive skills than those who do not.¹⁰

Take care especially to avoid foods that have been fortified with folic acid, the synthetic form of folate. Those with MTHFR gene mutations lack the enzyme required to activate folic acid, which can result in a buildup of unmetabolized folic acid (UMFA).

High amounts of red meat and dairy are also thought to contribute to higher homocysteine levels. Higher levels of homocysteine are typical in those with MTHFR, and this has been associated with higher risk factors for developing mood disorders such as depression and schizophrenia.¹¹

Foods high in sugar, gluten, refined grains, dairy, trans fats, and other additives are associated with triggering inflammation in the body and should be kept to a minimum.

Children with MTHFR mutations should eat plenty of folate-rich foods, including dark leafy greens (spinach, kale), fresh vegetables (broccoli, asparagus), legumes (beans, lentils), and avocado.

Foods rich in vitamins B6 and B12 are also crucial as these two nutrients work alongside folate in the methylation cycle, reducing homocysteine levels and supporting detoxification.

Natural foods such as fresh vegetables, fruits, and fresh meats have also been shown to improve homocysteine levels.¹²

Supplementing with methylfolate, vitamin B6, vitamin B12, and betaine has been shown to help control or alleviate the risk of elevated homocysteine. The B vitamins play a major role in both homocysteine metabolism and also the synthesis of glutathione (the body's master antioxidant).

Click here to learn more about why methylfolate is the best for anyone suffering from gene mutations such as MTHFR.

Essential fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from fish oil are shown to help reduce inflammation in the body while supporting healthy cognitive function and normal development in children.¹³

Gut bacteria are responsible for producing mood-regulating chemicals, including dopamine, serotonin, and gamma-aminobutyric acid, or GABA. Several studies have confirmed the link between gut health and behavior in children.

Autism is known to have comorbidity with a variety of gut disorders, and abnormalities in gut bacteria have been linked to depression, anxiety, and hyperactivity in children. A 2020 study found that the gut bacteria of school-aged children with behavior problems differed from that of their well-behaved peers.¹⁴

Along with a diet rich in whole, natural foods, probiotics can help support a child's gut health. Probiotics may have a range of benefits for children, with one review showing that supplementation improved prosocial behavior in children with autism as well as increasing species of beneficial bacteria in the gut. Another study suggested that probiotics can reduce the likelihood of developing Attention Deficit Hyperactivity Disorder (ADHD) or ASD.¹⁵

Fiber is also important for assisting with proper digestive function, maintaining healthy microbial balance in the gut, and supporting normal detoxification. Fiber also plays a key role in blood sugar management and healthy weight.

Your child's diet should include plenty of high-fiber foods such as whole grains, nuts, and raw fruits and vegetables.

Methylation is an important process of detoxification, particularly in the detoxification of inorganic arsenic and other toxins. Reduced methylation capacity has been shown to increase the risk of arsenic-related diseases.¹⁶

An impaired ability to detoxify can result in an accumulation of toxins. Research has confirmed that children with autism have higher levels of toxic metal accumulation, which may be linked to the etiology of autism.¹⁷

Children with behavioral disorders are often picky eaters and may have gastrointestinal disorders and/or malabsorption issues. They may already be on restricted diets that limit their intake of nutrients, which is when a multivitamin may be recommended.

A nutrient-dense diet is crucial for the rapidly developing brain. Without the right nutrients, young and older children may not develop the skills to function properly, particularly in terms of processing the world around them and maintaining their concentration.

• Fat-soluble vitamins such as vitamins A, D, E, and K play integral roles in vision, bone health, immune function, and coagulation.

• B vitamins assist with energy production, cognitive function, methylation, and numerous other roles. Active/methylated forms of these vitamins are essential for optimal absorption and methylation, particularly folate (methylfolate) and methylB12 (methylcobalamin, adenosylcobalamin, or hydroxocobalamin).

• Vitamin C is required for immune function and antioxidant protection

• Glutathione (GSH) is the body’s “master antioxidant” and can assist with proper detoxification and methylation.¹⁸

Look for a multivitamin that contains methylated vitamins and that has been third-party tested to ensure quality and purity. Check that it contains no artificial colors, flavors, artificial ingredients, or allergens such as gluten or dairy.

Methyl-Life Chewable Methylated Multivitamin is a great option for kids. It tastes like a sweet treat (but contains xylitol, not sugar!) and provides both L-Methylfolate and Active B12, essential nutrients for those with MTHFR and/or autism spectrum disorders.

This popular multivitamin also contains all of the bioactive vitamins mentioned above, plus patented minerals, antioxidants, and specific nutrients to support healthy methylation and cognitive function. The perfect daily nutritional support to fill in any ‘gaps' in a child's diet.