Interestingly, while TNFα, inhibits methionine synthase (MTR) expression in cultured neuronal cells, and MTR expression is very high in the postmortem brains of normal individuals in early developmental periods (but decreases as age increases), in patients with autism not only is its early life peak absent but also a life-long decrease in MTR expression is observed compared to the control subjects [20]. This evidence concerns the gene MTR and autism.