Association of SPINK5 gene polymorphisms with atopic dermatitis in Northeast China

Background Defect in the SPINK5 gene is known to be implicated in Netherton syndrome (NS), and has been suggested to be a locus predisposing to atopy in general. Coding polymorphisms in SPINK5 exons 13, 14 and 26 have been reported to be associated with atopic dermatitis (AD), asthma and high level of IgE. Objectives To examine whether the SPINK5 gene polymorphisms are associated with AD in Northeast China, and to assess how variants influence selected phenotypic traits. Methods A case-control study was conducted on four non-synonymous polymorphisms in the coding region of SPINK5 in AD and controls. The SPINK5 gene polymorphisms were analyzed using the PCR and RFLP methods. Results For the four non-synonymous SNPs, A1103G(Asn368Ser), G1156A(Asp386Asn), G1258A(Glu420Lys), G2475T(Glu825Asp) in SPINK5, the allelic frequencies in the AD cohort were 0.55 for 1103G, 0.57 for 1156A, 0.54 for 1258A, 0.62 for 2475T, consistent with those already published in the original British and Japanese cohorts. The T allele of SNP 2475G > T was found to be significantly associated with AD. There were significant differences in genotype frequencies for G1258A(Glu420Lys) and G2475T(Glu825Asp) but not for A1103G(Asn368Ser) and G1156A(Asp386Asn). Genotypes GA(420Glu/Lys), TT (2475Asp/Asp) and GT(2475Glu/Asp) were significantly more frequent in AD. However, the SPINK5 gene polymorphisms was found not to be associated with AD in regard to either serum IgE levels, concurrent allergic asthma or early onset of AD. Conclusions Our study confirms the association between SPINK5 and AD.