HLA-DRB1 and Parkinson disease: We noticed that the allele frequencies of HLA-DRB1*0403, another subtype of HLA-DRB1*04, was presented higher in PD patients than in healthy controls in series 1 although the difference was not significant after Bonferroni adjustment (0.0307 vs. 0.0159, p = 0.035, pc = 1).