Association analysis of HLA-DRA in Chinese patients with sporadic Parkinson's disease.

Our aim is to explore the linkage between single nucleotide polymorphisms (SNPs) in human leukocyte antigen (HLA)-DRA and Parkinson's disease (PD). 542 sporadic PD patients and 674 healthy controls were recruited to investigate this association in the Chinese population by the screening of 15 SNPs in HLA-DRA, and the association of rs3129882 was further re-evaluated by performing meta-analysis and meta-regression analysis. No SNPs in HLA-DRA were significantly associated with PD in the Chinese patients. Although the rs3129882 allele-G frequency in the Caucasian population was lower than that in Chinese population, meta-analysis showed no association of rs3129882 allele-G with PD in the Chinese or Caucasian population. In consideration of the heterogeneity (I(2)=78.6%, Q=66.33, p<0.000), subgroup analysis was performed, revealing a significant association between rs3129882 and PD in the Caucasian patients from the genome-wide association studies (OR=1.22, 95% CI: 1.16, 1.27); however, this association was not consistently observed in the studies performed using other DNA sequencing techniques. Meta-regression analysis, which accounted for 58.3% of the heterogeneity, revealed that the impact of the sequencing technique used was significant (p=0.027) compared with ethnicity. Regression analysis of the Caucasian population further showed that the sequencing technique used contributed to 71.2% of the heterogeneity (p=0.033). Our data support the absence of a linkage between the risk loci in HLA-DRA and PD in Chinese patients. The different DNA sequencing techniques used in PD studies may largely account for the controversial conclusions concerning rs3129882.