For example, we confirmed the results of previous studies that HLA-DRA*01, -DRB4*01:03, -DRB5*01, -DQB1*05 and -C*07:01:01 are predisposing alleles and that HLA-DRB1*04:04, -DQA1*03:01, -DQA1*03:02, and -DQB1*03:02, are protective in PD (34–37, 57). Here, HLA-DRB1 is linked to Parkinson disease.