COMT and 22q11.2 deletion syndrome: In addition, the COMT genotype is found to modulate cognitive functioning, relying on frontal DA neurotransmission, in psychotic disorder (Jonas et al., 2014; Slifstein et al., 2015) and in 22q11DS (Gothelf et al., 2005; de Koning et al., 2012; Carmel et al., 2014).