HLA-C and schizophrenia: Thus, even though genetic evidence for involvement of RGS1 in “whole” schizophrenia comprising all clinical cases is sparse at this moment, a functional link to the major histocompatibility complex (MHC), the most consistently identified common variant in schizophrenia with the highest LOD score5, suggests that RGS1 itself could well play a so far underappreciated role in schizophrenia.