Polymorphisms of TAP1/LMP7 loci in Egyptian patients with vitiligo

ABSTRACT

Vitiligo is a very common, often heritable acquired disorder characterized by well-circumscribed milky white cutaneous macules devoid of identifiable melanocytes. Vitiligo appears to be more commonly observed in parts of the body exposed to the sun and in darker skin types and may develop at any age. Our study contained 47 unrelated Egyptian young-aged vitiligo patients [age range 2-18 y] and 14 healthy volunteers of matched age range. All patients experienced active vitiligo lesions with no signs of other autoimmune disorders. To genotype the TAP1 [C>T intron 7] and LMP7 [G>T intron 6], we amplified the genomic DMA using polymerase chain reaction [PCR] using genomic DNA followed by enzymatic digestion. Our results showed no significant difference between TAP1 C>T [intron 7] and LMP7 G>T [intron 6] alleles and healthy controls [p= 0.3 or 0.5, respectively]. Even so, the odd ratios [ORs] for the genotypes of the TAP1 [C>T] were 1.78 [0.4 to 7.0], 0.8 [0.5 to 1.2], and 1.19 [0.2 to 4.9] for the TAP1-CC, CT, TT-genotypes, respectively. The ORs of LMP7 [intron G>T] genotypes were 1.4 [0.3 to 6.0], 0.8 [0.5 to 1.3], 1.19 [0.3 to 3.6] for GG, GT, and TT, respectively. However, a major contribution of both TAP1 and LMP7 polymorphisms to vitiligo susceptibility cannot be excluded. Further studies of other alleles within the TAP and LMP gene regions in Egyptian patients is recommended to demonstrate a possible role for MHC class I antigen processing and/or presentation pathway in the antimelanocyte autoimmune response in vitiligo pathogenesis