Genetics of psoriasis and psoriatic arthritis: update and future direction.

Psoriasis and psoriatic arthritis (PsA) both have substantive genetic determinants. Numerous candidate regions and genes have now been replicated in disease susceptibility, and to a lesser extent in disease expression, in both disease entities. Intensive efforts are now under way or are being planned to perform genome-wide association scans (GWAS) in psoriasis and PsA. A major determinant of success for GWAS is likely to be accumulation of multiple large well-phenotyped cohorts, sophisticated data management, and verification of the findings. At the 2007 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), members of the GRAPPA genetics committee presented a discussion of the genetics of psoriasis and PsA, including future trends. This article is a summary of that presentation and a review of the literature.