Association of genetic variants of the vitamin D receptor gene with vitiligo in a tertiary care center in a Saudi population: a case-control study

Abstract

BACKGROUND: Vitiligo is a common cutaneous disorder of the skin and hair caused by a systemic depigmentation disorder that affects 1% of the population or less due to its onset in early adulthood. Meta-analyses have documented a linkage between vitiligo and the vitamin D receptor (VDR) gene. OBJECTIVE: Investigate the relationship between the ApaI, BsmI, FokI and TaqI genetic variants in the VDR gene with vitiligo in a Saudi population. DESIGN: Case-control. SETTING: Single tertiary care center. PATIENT AND METHODS: The case-control study was carried out between January 2015-December 2015 in Saudi vitiligo patients and healthy controls. VDR genetic variants or polymorphisms (ApaI, BsmI, FokI and TaqI) were genotyped by polymerase chain reaction-restriction fragment length analysis followed by 3% agarose gel electrophoresis. Applicable statistical methods were used to assess relationships between vitiligo cases and controls. MAIN OUTCOM MEASURE: Effect of genotype distribution among four single nucleotide polymorphisms. SAMPLE SIZE: 152 vitiligo (median [IQR] 23 [19] years) patients and 159 healthy controls (45 [28.5] years). RESULTS: We found an association of vitiligo with ApaI and BsmI polymorphisms (P<.05). However, a decreased risk was noted in vitiligo patients with FokI and TaqI polymorphisms and in the diplotype and haplotype analysis within males and females. A positive association with vitiligo was observed in ACAC and AC (adjusted by gender) haplotypes (P<.05). The strongest linkage disequilibrium was observed between rs79785232 (ApaI) and rs731236 (TaqI) polymorphisms (r2=.83), followed by rs2228570 (FokI) and rs1544410 (BsmI) polymorphisms (r2=.53). CONCLUSIONS: Our results confirm an association of vitiligo with ApaI and BsmI polymorphisms and fail to show an association in TaqI and FokI polymorphism with vitiligo. Additional studies need to be carried out in different Arab populations to determine whether the polymorphisms are present. LIMITATIONS: Controls not age matched, small sample size, lack of biochemical parameters. CONFLICT OF INTEREST: None.