MTHFR in Children: Signs Symptoms and Risk Factors

Written By:

Katie Stone - Naturopath

Medical Reviewer:

Dr. Nare Simonyan - PhD Pharmaceutical Science

Edited By:

Kari Asadorian - Bachelor of Science in Nursing

Updated On:

February 18, 2025

Symptoms/early signs of MTHFR in babies

The MTHFR genetic mutation does not typically produce signs or symptoms in babies or young children.

However, some MTHFR variants are a risk factor for neural tube defects such as spina bifida. This risk is highest with the homozygous MTHFR 677TT, which is associated with approximately a 70% increased risk for spina bifida.¹

A mutation on the MTHFR gene may lead to impaired function of the MTHFR enzyme, which may lead to a deficiency in folate and several other nutrients. Folate is required during the period of the rapid growth in infancy and childhood, and deficiency during early childhood can lead to poor growth and impaired brain development.²

Symptoms of MTHFR in children

Symptoms of MTHFR mutations in children are mostly behavioral.

Research has linked the MTHFR mutation to psychiatric conditions such as major depression, bipolar disorder, and schizophrenia. Some studies show higher frequency of C677T mutation in children with autism and in behavioral disorders such as ADHD.³ However, signs of these disorders may not present until the child is at least three years old.

Congenital heart defects (CHD) and spinal deformities are also linked to folate deficiency in children. A meta-analysis on 724 children with CHD and 760 healthy children found that the presence of the MTHFR A1298C mutation increased the risk of developing a congenital heart defect 1.36-fold.⁴

Some sources have claimed a relationship between MTHFR mutations and physical characteristics such as tongue ties, stork bites, sacral dimples, and other defects. However, there are no studies to support these claims. A ‘stork bite’ is actually a nevus simplex (pink patches on the face), which is present in 30-50% of all newborns, regardless of whether the baby has MTHFR.⁵

Does MTHFR affect children differently?

MTHFR may impact a child’s development if it causes folate deficiency. Folate is a critical component of normal brain development in infancy and childhood, and deficiency has been linked to several health conditions including anemia, spina bifida, congenital heart defects, and some mental health disorders such as depression.⁶

Connection of autism and ADHD and MTHFR in children

A meta-analysis showed that MTHFR C677T is significantly associated with autism in all five genetic profiles: allelic, dominant, recessive, heterozygous, and homozygous. However, MTHFR A1298C is not found to be significantly associated with autism.⁷

Some research has shown that certain genetic variants involved in the folate metabolism pathway are significantly linked to ADHD. These variants included MTRR, RFC1, MTHFR, and BHMT genes, which suggests that genetic variants related to folate metabolism may influence ADHD traits.⁸

Is There a Link Between MTHFR Mutations and Autism in Children?

Developmental and neurological health issues

Some studies have linked severe MTHFR deficiency (reduced enzyme function) to developmental delays, neurological and vascular issues, and/or thrombosis. However, these cases are generally rare.⁹

Digestive issues

Folate deficiency can cause glossitis, diarrhoea, gastrointestinal lesions, and poor growth.¹⁰

Anemia

MTHFR may affect red blood cell production, potentially increasing the risk of anemia and thrombocytopenia.¹¹

High homocysteine

A 2019 study found that the MTHFR 677TT genotype was linked to elevated homocysteine levels in adolescents but not in younger children. The researchers explained that this finding was likely due to the younger group having higher folate levels.¹²

Product Recommendations

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Frequently Asked Questions about MTHFR symptoms in kids

Is methylfolate safe for children?

L-methylfolate calcium has been tested and is well-tolerated by children and adolescents, and may be helpful for those with mental health disorders.¹³

How much methylfolate for an 11 year old?

The exact dosage recommendations for methylfolate have not yet been established by the FDA. Refer to our dosage instructions page for additional information.
Current dietary recommendations for folate (as established by the Health and Medicine Division of the National Academy of Sciences) are:

Infants 0-6 months: 65 mcg DFE
Infants 6 -12 months: 80 mcg DFE
Children 1-3 years: 150 mcg DFE
Children 4-8 years: 200 mcg DFE
Boys and Girls 9-13 years: 300 mcg DFE
Teenagers 14-18 years: 400 mcg DFE

What are the negative effects of methylfolate?

Methylfolate is unlikely to produce negative effects if it is taken in the correct dosage.

Some side effects of L-methylfolate may include (according to RxList)¹⁴

➧ Altered sleep patterns
➧ Difficulty concentrating
➧ Irritability, hyperactivity
➧ Confusion or impaired judgment
➧ Weight loss
➧ Nausea
➧ Abdominal distention, gas (flatulence)
➧ Bitter taste in the mouth

Is too much folate bad for kids?

Excess intake of any nutrient can be harmful for children. Consult your healthcare professional before giving your children any new supplements.

Note: A mutation in the MTHFR gene may not necessarily lead to a deficiency in folate or a serious health issue in children.
Various studies suggest that 60-70% of the global population are carriers of a MTHFR variant, and a lot of people do not experience symptoms.¹⁵

References

Raffaella de Franchis, Lorenzo D Botto, Gianfranco Sebastio, Roberta Ricci, Achille Iolascon, Valeria Capra, Generoso Andria, Pierpaolo Mastroiacovo; "Spina bifida and folate-related genes: A study of gene-gene interactions"; Genetics in Medicine; 2002 May

https://www.nature.com/articles/gim200226
Aakriti Gupta, Umesh Kapil, Lakshmy Ramakrishnan, Ravindra Mohan Pandey, Chander Prakash Yadav; "Prevalence of Vitamin B12 and Folate Deficiency in School Children Residing at High Altitude Regions in India"; Indian journal of pediatrics; 2017 Apr

https://pubmed.ncbi.nlm.nih.gov/28108882/
Robin P Goin-Kochel, Anne E Porter, Sarika U Peters, Marwan Shinawi, Trilochan Sahoo, Arthur L Beaudet; "The MTHFR 677C-->T polymorphism and behaviors in children with autism: exploratory genotype-phenotype correlations"; Autism research; 2009 Apr

https://pubmed.ncbi.nlm.nih.gov/19455642/
Nataša Karas Kuželički, Bojan Doljak; "Congenital Heart Disease and Genetic Changes in Folate/Methionine Cycles"; Genes; 2024

https://www.mdpi.com/2073-4425/15/7/872
Reuters; "Fact check: These birthmarks are not indicators of a MTHFR gene mutation and other false claims"; reuters.com; 2020 Sep

https://www.reuters.com/article/uk-factcheck-birthmarks-not-mthfr-gene-v-idUSKBN25U2UL
National Institutes of Health; "Folate"; 2022 Nov

https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
Tahereh Sadeghiyeh, Seyed Alireza Dastgheib, Khadijeh Mirzaee-Khoramabadi, Majid Morovati-Sharifabad, Mohammad Javad Akbarian-Bafghi, Zahra Poursharif, Seyed Reza Mirjalili, Hossein Neamatzadeh; "Association of MTHFR 677C>T and 1298A>C polymorphisms with susceptibility to autism: A systematic review and meta-analysis"; Asian journal of psychiatry; 2019 Dec

https://pubmed.ncbi.nlm.nih.gov/31614268/
Tanusree Saha, Mahasweta Chatterjee, Deepak Verma, Anirban Ray, Swagata Sinha, Usha Rajamma, Kanchan Mukhopadhyay; "Genetic variants of the folate metabolic system and mild hyperhomocysteinemia may affect ADHD associated behavioral problems"; Progress in Neuro-Psychopharmacology and Biological Psychiatry; 2018 Jun

https://www.sciencedirect.com/science/article/abs/pii/S0278584617307613
Shanel Raghubeer, Tandi E Matsha; "Methylenetetrahydrofolate (MTHFR), the One-Carbon Cycle, and Cardiovascular Risks"; Nutrients; 2021 Dec

https://pmc.ncbi.nlm.nih.gov/articles/PMC8703276
Henk J Blom, Yvo Smulders; "Overview of homocysteine and folate metabolism. With special references to cardiovascular disease and neural tube defects"; Journal of inherited metabolic disease; 2011 Feb

https://pubmed.ncbi.nlm.nih.gov/20814827/
Sabrina Giammarco, Patrizia Chiusolo, Roberto Maggi, Monica Rossi, Gessica Minnella, Elisabetta Metafuni, Francesco D’Alò, Simona Sica; "MTHFR polymorphisms and vitamin B12 deficiency: correlation between mthfr polymorphisms and clinical and laboratory findings"; Annals of hematology; 2024 Aug

https://pmc.ncbi.nlm.nih.gov/articles/PMC11512882
Helena Caldeira-Araújo, Ruben Ramos, Cristina Florindo, Isabel Rivera, Rita Castro, Isabel Tavares de Almeida; "Homocysteine Metabolism in Children and Adolescents: Influence of Age on Plasma Biomarkers and Correspondent Genotype Interactions"; Nutrients; 2019 Mar

https://pmc.ncbi.nlm.nih.gov/articles/PMC6471758/
Michelle Rainka, Traci Aladeen, Erica Westphal, Jacqueline Meaney, Fran Gengo, Jessica Greger, Horacio Capote; "L-Methylfolate Calcium Supplementation in Adolescents and Children: A Retrospective Analysis"; Journal of psychiatric practice; 2019 Jul

https://pubmed.ncbi.nlm.nih.gov/31291206/
John P. Cunha; "L-methylfolate"; rxlist.com; 2025

https://www.rxlist.com/l-methylfolate/generic-drug.htm
Thomas G Deloughery, Beverley J Hunt, Geoffrey D Barnes, Jean M Connors, The WTD Steering Committee; "A call to action: MTHFR polymorphisms should not be a part of inherited thrombophilia testing"; Research and practice in thrombosis and haemostasis; 2022 Jun

https://pmc.ncbi.nlm.nih.gov/articles/PMC9175241/

About the Author

Katie is a qualified Naturopath (BNatMed) and freelance writer from New Zealand. She specializes in all things health and wellness, particularly dietary supplements and nutrition. Katie is also a dedicated runner and has completed more half-marathons than she can count!

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