MTHFR C677T is not a risk factor for autism spectrum disorders in South Brazil

Abstract

Many studies have suggested that autism may be associated with metabolic abnormalities in the folate/homocysteine pathway, which is involved in DNA methylation, thus altering gene expression. One of the most important polymorphisms in this pathway is C677T of the methylenetetrahydrofolate reductase gene, because the T allele is associated with a decrease in enzymatic activity. We evaluated the association between C677T polymorphism and autism spectrum disorders through a case--control study. In addition, we analyzed the influence of this polymorphism on certain autistic behaviors like complex body movements, self-injury and averted gaze according to the Autism Diagnostic Interview-Revised. The analyses involved 151 children with idiopathic autism spectrum disorder and 100 healthy control children. The frequency of the T allele was 0.38 for the case group and 0.35 for the control group (P=0.77). The genotypic distribution did not show significant differences between cases and controls (P=0.72), nor association between the T allele and selected behaviors.

Evaluation of C677T Polymorphism of the Methylenetetrahydrofolate Reductase (MTHFR) Gene in various Neurological Disorders

“…There are conflicting reports suggesting both a positive and negative association of MTHFR C677T polymorphism with autism [45,46]. In our study, a positive association was observed between MTHFR C677T variant allele and autism risk.…”

MTHFR rs1801133 Gene Polymorphism and Autism Susceptibility

“…A similar study with the Chinese Han population also supported the notion that MTHFR C677T polymorphism is associated with increased risk of ASD [34]. However, a study performed in south Brazil showed that MTHFR C677T alone is not a risk factor for ASD [35].…”

Methylenetetrahydrofolate Reductase Polymorphisms C677T and Risk of Autism in the Chinese Han Population

“…The MTHFR C677T polymorphism converts an alanine residue to a valine (ALA222VAL), leading to a lower enzymatic activity Mansoor et al, 2009). Some studies have shown that autism might be associated with metabolic abnormalities in the folate/homocysteine pathway, which is involved in DNA methylation, thus altering gene expression (dos Santos et al, 2010). The association between the MTHFR C677T polymorphisms and risk of autism is still controversial and ambiguous ( James et al, 2006;Rogers, 2008;Goin-Kochel et al, 2009;Mohammad et al, 2009;Pasca et al, 2009;dos Santos et al, 2010;Liu et al, 2011;Schmidt et al, 2011).…”