The MTHFR 677C-->T polymorphism and behaviors in children with autism: exploratory genotype-phenotype correlations.
Kids with autism who carry the MTHFR 677 T allele may show more gaze avoidance, complex movements, self-injury history, and over-activity—something to flag when reviewing genetic reports.
01Research in Context
What this study did
The team looked at one gene in kids with autism. The gene is called MTHFR.
They asked: do kids with the T version show different behaviors?
Parents answered questions from the ADI-R. The study checked four problem items.
What they found
Kids who carry at least one T allele had higher odds of four behaviors.
These were gaze avoidance, complex movements, self-injury history, and over-activity.
The finding was significant.
How this fits with other research
Liu et al. (2011) extends this idea. They showed the same T allele is more common in autism cases from simplex families.
Stichter et al. (2009) links the allele to behaviors. Liu et al. (2011) links it to risk. Together they build a picture: the variant may both raise risk and shape behavior.
No direct clash appears. The two papers simply focus on different ends of the same gene.
Why it matters
When you read a genetic report, look for MTHFR 677 T. If it is there, plan for extra focus on self-injury and over-activity. Track gaze and stereotypy early. Share the finding with the medical team. It may guide diet or folate choices.
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02At a glance
03Original abstract
New evidence suggests that autism may be associated with (a) varied behavioral responses to folate therapy and (b) metabolic anomalies, including those in folate metabolism, that contribute to hypomethylation of DNA. We hypothesized that children with autism who are homozygous for the MTHFR 677 T allele (TT) and, to a lesser extent those with the CT variant, would exhibit more behavioral problems and/or more severe problematic behaviors than homozygous wild-type (CC) individuals because of difficulties in effectively converting 5,10-MTHF to 5-MTHF. Data from the Autism Genetic Resource Exchange (AGRE) collection were analyzed for all children who met strict criteria for autism per the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) and who had been genotyped for the 677 C to T MTHFR polymorphism (n=147). Chi-square tests, logistic regression, and one-way ANOVAs were used to determine whether differences existed among MTHFR genotypes for specific behaviors on the ADI-R and indices for level of functioning. Exploratory results indicated four behaviors from the ADI-R that were more common and problematic (95% CI) among those with at least one copy of the T allele as compared to homozygous wild-type individuals: direct gaze, current complex body movements, a history of self-injurious behavior, and current overactivity (ORs=2.72, 2.33, 2.12, 2.47, respectively). No differences existed among genotypes for level of functioning as measured with the Peabody Picture Vocabulary Test-Third Edition, Ravens Colored Progressive Matrices, or the Vineland Adaptive Behavior Scales. Findings call for further investigation of the relationship between folate metabolism and problem behaviors among children with autism.
Autism research : official journal of the International Society for Autism Research, 2009 · doi:10.1002/aur.70