NOTCH4 and schizoaffective disorder: The Notch receptor 4 gene encodes a member of the NOTCH family of proteins. Notch signaling is an evolutionarily conserved intercellular signaling pathway that regulates interactions between physically adjacent cells. This receptor may play a role in vascular, renal and hepatic development. NOTCH4-associated diseases include arteriovenous malformation and schizoaffective disorder.