Homocysteine, B Vitamins, and Autism Spectrum Disorders (ASD)

Previous studies have suggested a link between serum levels of homocysteine and B vitamins and autism spectrum disorders. However, the causal relationships between these traits remained unexplored. In this study, researchers used Mendelian randomization analyses to assess causal relationships between 47 single nucleotide polymorphisms (13 related to homocysteine, 13 to vitamin B9, 14 to vitamin B6, and 7 to vitamin B12) and the risk of autism spectrum disorders. A statistical association was identified between genetically predicted serum vitamin B12 levels and the risk of autism spectrum disorder with one of the methods used, but not with the others. No causal relationship was found between the risk of autism spectrum disorder and other B vitamins or homocysteine.