Abstract
Saitohin gene found within the tau gene is thought to play a role in the pathogenesis of neurodegenerative diseases. The rs62063857 polymorphism originally found in the saitohin gene seems to be the responsible SNP in this event. This polymorphism is studied mostly in patients with Alzheimer's disease. Data on Parkinson's disease are scarce. Therefore, we examined the rs62063857 polymorphism in 583 Parkinson's disease patients (347 male and 236 female) and 396 healthy controls (238 male and 158 female) by a polymerase chain reaction and restriction fragment length polymorphism method to see whether it was associated with Parkinson's disease from the City of Istanbul, Turkey. The G allele frequency was 22 % in overall controls and 16 % in Parkinson's disease patients. In this study, the saitohin rs62063857 polymorphism was associated with Parkinson's disease (χ2 = 16.765; P = 0.000). Individuals with the AA genotype showed 1.7-fold increased risk for Parkinson's disease (χ2 = 16.680; P = 0.000), whereas individuals with the AG genotype revealed protection against Parkinson's disease (χ2 = 14.554; P = 0.000). After the stratification analysis according to gender, both male and female PD patients showed association with the alleles and genotypes of the rs62063857 polymorphism of the saitohin gene (χ2 = 9.476, P = 0.009; χ2 = 7.593, P = 0.022, respectively). When the Parkinson's patients were divided into two groups with regard to onset of the disease, both groups showed association with the disease. The Parkinson's patients with disease onset below 65 years of age showed 1.8-fold increased risk for the disease. The Parkinson's patients with disease onset over 65 showed more robust association with a 2.051-fold increased risk for the disease. Consequently, the rs62063857 polymorphism of the saitohin gene is a genetic risk factor for Parkinson's disease. Hence, this polymorphism may play a role in the etiology of Parkinson's disease.