MICA 5.1 allele is a susceptibility marker for psoriasis in the Korean population

In order to investigate the possibility that the MICA gene is involved in t he pathogenesis of psoriasis, microsatellite polymorphism in the transmembr ane region of MICA was studied in 138 Korean patients with psoriasis and co mpared with 126 healthy controls. The MICA 5.1 microsatellite allele, consi sting of 5.1 repetitions of GCT/AGC, showed significantly higher frequencie s in all patients and in patients with type I psoriasis than in the control s. HLA-A30-B13-Cw*0602-MICA 5.1 and A1-B37-Cw*0602-MICA 5.1 were found to b e an extended haplotype associated with psoriasis. Our results suggest that the MICA 5.1 allele might be a genetic marker related to the early onset o f psoriasis and play a secondary role to the HLA-Cw*0602 gene or an unknown causative gene closely linked to HLA-Cw*0602 in the genetic susceptibility to psoriasis.