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.
aDepartamento de Genética, Universidade Federal do Rio Grande do Sul
bServiço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
Correspondence to Dr Lavínia Schüler-Faccini, MD, PhD, Departamento de Genética. Instituto de Biociências, UFRGS, Caixa Postal 15031, Porto Alegre, RS 91501-970, Brazil
Tel: +55 51 3308 9826; fax: +55 51 3308 9823;
Received 17 October 2009 Revised 21 February 2010 Accepted 11 March 2010