OBJECTIVETo determine whether there are any associations between the -258T/G polymorphism of the promoter and the IVS3 -20T/C polymorphism in parkin gene and Parkinson's disease (PD) from a Han population in Sichuan province.

METHODSPolymerase chain reaction (PCR), restriction fragment length polymorphism, denaturing high performance liquid chromatography(dHPLC) and sequence analysis were used to determine the genotype of each subject. The -258T/G polymorphism and IVS3 -20T/C polymorphism were analysed in 198 patients with sporadic PD and 187 healthy controls, matched for age and gender.

RESULTSThere were significant differences in allele frequency of the -258T/G polymorphism between PD patients and controls, with the G allele more common in cases than controls (52.5% vs 43.3%; chi square is 6.17, P< 0.025, OR is 1.45, 95% CI 1.04-1.86). There were also significant differences in G allele frequency between PD patients with onset age over 50 years old and controls(chi square is 9.048, P< 0.01, OR is 1.57, 95% CI:1.08-2.06). The frequency of TG+GG genotype was significantly higher in PD patients than in controls (78.79% vs 69.51%; chi square is 3.854, P< 0.05, OR is 1.63, 95% CI:0.88-2.38). In addition, there were significant differences in age of onset between PD patients with different genotypes (P< 0.05). The average age of onset in group of GG genotype was later about 5 years compared with the group of TT or TG genotype. The frequency of CC genotype in IVS3 -20T/C polymorphism was much higher than that of TC genotype. No TT genotype was found.

CONCLUSIONThis study suggests that the parkin promoter -258T/G polymorphism might be a risk factor for late onset PD in Sichuan. CC genotype for IVS3 -20T/C polymorphism is common in Sichuan Han population. No TT genotype for IVS3 -20T/C polymorphism is found in Sichuan Han population.