SYN1 and mood disorder: To date there is no evidence of altered DNA methylation of these genes in mood disorders; only one study of a single schizophrenia patient suggests potentially variably methylated sites in the distal SYN3 promoter [3] and a recent study in rats proposes that early life stress, a precipitant of depressive behavior, leads to SYN1 transcription start site hypermethylation and related mRNA downregulation in the amygdala [4].