Role of the HI haplotype of microtubule-associated protein tau (MAPT) gene in Greek patients with Parkinson's disease

Background: The extended tau haplotype (HI) that covers the entire human microtubule-associated protein tau (MAPT) gene has been implicated in Parkinson's disease (PD). Nevertheless, controversial results, such as two studies in Greek populations with opposite effects, have been reported. Therefore, we set out to determine whether the HI haplotype and additional single nucleotide polymorphisms (SNPs) included in HI are associated with PD in a sample of Greek patients. Methods: We analysed MAPT haplotypes in cohorts of 122 patients and 123 controls of Greek origin, respectively. SNP genotyping was performed with Taqman assays and genotyping results were confirmed by sequencing. Results: The presence of the HI haplotype was significantly associated with PD (odds ratio for H1H1 vs. H1H2 and H2H2: 1.566; 95% CI: 1.137-2.157; P = 0.006) and remained so after adjustment of sex. Further analysis of H1 sub-haplotypes with three single nucleotide polymorphisms (rs242562, rs2435207 and rs3785883) demonstrated no significant association with PD. Conclusion: Our data support the overall genetic role of MAPT and the H1 haplotype for PD susceptibility in Greek patients. However, the previously supported association of H1 sub-haplotypes with PD could not be confirmed in our study.