A partial 22q11.2 deletion that includes several genes related to the neuropsychiatric phenotype, catechol-O-methyltransferase (COMT) (Xiu et al., 2015) and thioredoxin reductase 2 (TXNRD2) (Kariž et al., 2015), is associated with the onset of T2DM. This evidence concerns the gene COMT and type 2 diabetes mellitus.