SULT4A1 and Phelan-McDermid syndrome: Disruption of SULT4A1 expression contributes to neurodevelopmental syndromes; Sequence polymorphisms in the 5’-UTR and haploinsufficiency of the SULT4A1 gene (deletions at loci 22q13.3) are associated with schizophrenia and Phelan-McDermid syndrome, an autism spectrum disorder13–17.