Association of Vitamin D Receptor Genotypes in Sporadic and Familial Parkinson’S Disease



Ostadsharif M¹ ; Meamar R^{2, 3} ; Asadian M⁴ ; Izadi M⁵ ; Javadirad M⁶ ; Chitsaz A⁷
Source: Journal of Isfahan Medical School Published:2014

Abstract

Background: The association of vitamin D and Parkinson's disease (PD) has recently been proposed which acts via vitamin D receptor (VDR). The vitamin D receptor gene contains a start codon polymorphism that can be detected with the restriction enzyme FokI. The aim of this study was to identify the association of FokI polymorphism in sporadic and familial form of Parkinson's disease. Methods: In present case-control study, blood samples were collected from 60 patients with Parkinson's disease in local Isfahan population (Iran) and 62 unrelated normal individuals from southwest region of Isfahan. Another part of the study was planned on evaluation of 6 patients with Parkinson's disease and 7 healthy controls from one family with the Parkinson's disease pedigree. The polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method used to determine genotypes. Serum levels of 25-hydroxyvitamin D (25OHD), parathyroid hormone, calcium, phosphorus and alkaline phosphatase from patients and controls of pedigree were analyzed. Findings: In sporadic Parkinson's disease, protection against the development of the disease was conferred when F allele existed, but it was not significant (OR = 0.7, 95%CI: 0.44-1.28, P = 0.29). On the other hand, insignificant susceptibility to Parkinson's disease was correlated to f allele (OR = 1.3, 95%CI: 0.437-1.283, P = 0.39). In familial study, that the risk ratio of Parkinson's disease in the sample was 4 folds higher for f allele (OR = 4.091, 95%CI: 0.374-44.788, P = 0.22); whereas, ff homozygosity for the FokI genotype was a non-significant genetic risk factor (2.7 times) for Parkinson's disease compared with other FokI genotypes (OR = 2.667, 95%CI: 0.193-36.756, P = 0.45). Patients with ff genotype compared with FF ones showed increased serum level of 25OHD, parathyroid hormone and alkaline phosphatase, but the associations were not significant. Conclusion: Our finding focused on FokI polymorphism alone, and then we need to analyze other polymorphisms in the vitamin D receptor gene, such as ApaI, TaqI and BsmI. Because of small population of the study, generalizing these results might be limited. © 2014, Isfahan University of Medical Sciences(IUMS). All rights reserved.