Through a collaborative effort of the Schizophrenia Working Group of the Psychiatric Genomics Consortium [234] and International Schizophrenia Consortium [235],, it was discovered that the locus most significantly associated with SZ lies within the extended human major histocompatibility complex (MHC), and the genomic region lies near the region encoding complement component C4. The gene discussed is HLA-C; the disease is schizophrenia.