HLA-DRB1 and psychiatric disorder: Chromosomes 6p21.2 and 6p21.32 belong to the chromosomal region of major histocompatibility complex, and have been previously linked to psychiatric disorders including schizophrenia6, 40 and bipolar affective disorder,41 as well as neurologic disease such as photosensitive epilepsy,42 late-onset Alzheimer disease43 and restless legs syndrome.44 In this study, we discovered novel suggestive associations of HLA-DRB1*01:01 and DRB1*04:04 with ASPD.