Genetics

Abstract

Consensus has not been established as to the susceptibility allele for psoriasis. Studies via linkage-based loci have universally confirmed the possibility of the susceptibility allele being present within the locus PSORS1 (a 300-kb region which extends from the HLA-B gene and includes the HLA-C gene) and involving the HLA-C gene located on chromosome 6p21. New developments greatly favor HLA-Cw*0602 as the susceptibility allele at locus PSORS1. This allele suggests that cytotoxic killer T lymphocytes (CD8+ T lymphocytes) are likely to be involved in autoantigen recognition in psoriasis. T cells are thought to recognize epidermal keratin peptides, presented in the context of the Cw6 protein. As psoriasis is a multifactorial disease which involves multiple genes with unpredictable interactions, this complicates understanding the genetic mechanism of inheritance. To date, there are at least 20 genetic loci that have been identified from linkage-based studies. Recent findings suggest that a variation at IL1RN may be responsible for nail changes. The following is a synopsis of existing literature on the genetics of psoriasis.