Combined haplotype analysis of the interleukin-19 and -20 genes: relationship to plaque-type psoriasis.
There is increasing evidence to suggest that the newly discovered cytokines interleukin (IL)-19 and -20 have a role in the function of epidermis and in psoriasis. The genes encoding these cytokines locate into the genomic IL-10 region on human chromosome 1. The aim of the present study was to analyze whether single-nucleotide polymorphisms (SNPs) in these genes have an impact on the susceptibility for psoriasis. From pairwise linkage disequilibrium (LD) matrix of the IL-19 and -20 gene polymorphisms, what reflects the nonrandom association of alleles at these markers, it was apparent that IL-19 and -20 genes form one block of LD. We found that the HT3 CACCGGAA haplotype of the IL-19 and -20 genes was associated with an increased risk of psoriasis, reflecting its role in determining susceptibility to plaque-type psoriasis. Although association analysis of the IL-19 gene indicated that minor alleles of the IL-19 gene SNPs (rs2243188, rs2243169 and rs2243158) revealed protective effect to psoriasis and haplotype analysis of the IL-19 gene proved significant protective effect of the TGATA haplotype in case of late-onset disease, combined haplotype analysis of the IL-19 and -20 genes demonstrated that protective effect of the IL-19 gene is secondary to the susceptibility effect of the IL-20 gene.
Kõks
S
S
Department of Physiology, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia. Sulev.Koks@ut.ee
Kingo
K
K
Rätsep
R
R
Karelson
M
M
Silm
H
H
Vasar
E
E
D000483:Alleles; D017931:DNA Primers; D004957:Estonia; D040461:Gene Components; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics*; D007378:Interleukins / Q000235:genetics*; D015810:Linkage Disequilibrium; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011565:Psoriasis / Q000235:genetics*; D012307:Risk Factors
D017931:DNA Primers; C421250:IL19 protein, human; D007378:Interleukins; D016753:Interleukin-10; C422042:interleukin 20