CD33 rs3865444 as a risk factor for Parkinson's disease.

Abstract BACKGROUND Alzheimer’s (AD) and Parkinson’s diseases (PD) share a few elements of their clinical, pathological and genetic backgrounds. The CD33 rs3865444 has emerged as a strong genetic locus associated with AD through genome-wide association study (GWAS). However, little is known for its role in PD. OBJECTIVE To assess the role of CD33 rs3865444 on PD risk. METHODS We genotyped 358 patients with PD and 358 healthy controls for theCD33 rs3865444. Odds ratios (ORs) with the respective 95% confidence intervals (CIs)], were calculated with the SNPStats software, assuming five genetic models (co-dominant, dominant, recessive, over-dominant and log-additive), with the G allele as the reference allele. RESULTS The CD33 rs3865444 was associated with decreased PD risk in the dominant [GG vs GT + TT; OR (95% CI) = 0.61 (0.45-0.82), p = 0.001], the over-dominant [GG + TT vs GT; OR (95% CI) = 0.65 (0.48-0.89), p = 0.0061], log-additive [OR (95% CI) = 0.67 (0.52-0.86), p = 0.0014], and co-dominant [with overall p = 0.0043, and OR (95% CI) = 0.62 (0.45-0.84) for the TG genotype compared to the GG], modes of inheritance. CONCLUSIONS The CD33 rs3865444 is associated with decreased PD risk, and larger studies investigating the role of CD33 rs3865444 on PD are needed.