COMT and 22q11.2 deletion syndrome: In the present study, we demonstrated approximately a 50% reduction in the expression levels of several candidate genes in the deleted region (COMT, DGCR6, DGCR8, ZDHHC8, TXNRD2 and SLC25A1) in peripheral blood leukocytes from young and adolescent participants with 22q11DS, and demonstrate a ∼50% decrease in mRNA levels when compared to controls.