Microtubule-associated protein tau (MAPT) influences the risk of Parkinson's disease among Indians.

Parkinson's disease (PD) is a neurodegenerative disease of the central nervous system and its prevalence increases with age. Microtubule-associated protein tau (MAPT), a neuronal protein is involved in the pathogenesis of several neurodegenerative diseases including PD. To determine the broader significance of this association with PD, replicative studies in distinct ethnic populations are required. In this study, we investigated MAPT for its potential association with PD using five haplotype-tagging SNPs and the del-In9 polymorphism of MAPT in 301 PD patients and 243 healthy controls from eastern India. Our case-control analysis did not show a significant association with any of the markers and PD. However, a risk haplotype [GAC+G] for PD was identified (OR=1.563; 95% CI=1.045-2.337; p=0.03). In addition, haplotype AAC+A (OR=2.787; 95% CI=1.372-5.655; p=0.004) was strongly associated with early onset PD (age at onset < or =40 years) and AAC+G haplotype showed a weak association (OR=2.233; 95% CI=1.018-4.895; p=0.045) with late onset PD (age at onset >40 years). This observation highlights the significance of rs7521 in modifying the age at onset of PD under a common haplotype background. We also identified AGC+A as a risk haplotype for sporadic cases (OR=2.773, 95% CI=1.198-6.407, p=0.016). This is the first association study from India conducted on MAPT among PD patients and provides valuable information for comparison with other ethnic groups.