For rs12985029, significant interactions were identified between it and disease status with cognitive functions in the domain of memory, specifically in immediate recall of logical memory (q = 0.003) and delayed recall of logical memory (q = 0.003) (Table 5), in which significant effects of CD33 SNPs on immediate recall of logical memory were observed specifically in the HBV (q = 0.025) and HCV (q = 0.023) cohorts, but not in the healthy control (q = 0.418) or Parkinson’s disease groups (q = 0.540). This evidence concerns the gene CD33 and Parkinson disease.