ITIH4 and schizophrenia: In recent years, a genome-wide association study (GWAS) of schizophrenia have identified several susceptibility loci, including ZKSCAN4 (zinc finger with KRAB and SCAN domains 4), NKAPL (NFκB activating protein-like), MIR137 (microRNA 137), WDR1 (WD repeat-containing protein 1), the ITIH3 (inter-alpha-trypsin inhibitor heavy chain 3)–ITIH4 (inter-alpha-trypsin inhibitor heavy chain family, member 4) region and genes within the extended major histocompatibility complex (MHC) region [10,11,12].