P12 ANALYSIS OF VITAMIN D RECEPTOR GENE ApaI AND TaqI POLYMORPHISMS IN ALOPECIA AREATA
Akar A, Orkunoglu EF, Tunca M, Kurumlu Z
Department of Dermatology and Immunology, GATA School of Medicine, Ankara, Turkey

Lack of Vitamin D receptor (VDR) is associated with reduced epidermal differentiation and hair follicle growth. Expression of VDR in keratinocytes is necessary for maintenance of the normal hair cycle. In addition, patients with hereditary 1,25-dihydroxyvitamin D3-resistant rickets type II and VDR knockout mice exhibit a phenotype that includes alopecia totalis. VDR gene polymorphisms influence susceptibility to a number of autoimmune diseases. The aim of this study was to determine whether there was a relationship between VDR gene ApaI and TaqI polymorphisms and alopecia areata (AA). Thirty-two unrelated patients (30 males and 2 females) with extensive forms of AA (patchy AA; scalp hair loss more than 75%, alopecia totalis, and alopecia universalis) and 27 healthy control subjects (24 males and 3 females) were genotyped. Their genotypes were determined by a polymerase chain reaction and restriction fragment length polymorphism analysis. Allele frequencies for A, T, a, and t alleles were 70.3%, 62.5%, 29.7%, and 37.5% in the alopecic group and 63.0%, 77.8%, 37.0%, and 22.2% in the control group, respectively. The frequencies for the AA, Aa and aa genotypes were 43.8%, 53.1% and 3.1% in the patient group, and 29.6%, 66.7% and 3.7% in the control group, respectively. The frequencies for the TT, Tt and tt genotypes were 37.5%, 50.0% and 12.5% in the patient group, and 63.0%, 29.6% and 7.4% in the control group, respectively. No statistically significant differences were observed in the frequencies of alleles and genotypes between the patient and the control groups in this study. These findings and our previous studies suggest that there is no relationship between VDR gene polymorphisms and AA. However, VDR gene polymorphisms should be further studied in other populations.