Sari Suomela, Kati Kainu, Päivi Onkamo, Inkeri Tiala, Johan Himberg, Lotta Koskinen, Erna Snellman, Seija-Liisa Karvonen, Jaakko Karvonen, Tutta Uurasmaa, Timo Reunala, Kristiina Kivikäs, Christer T. Jansén, Päivi Holopainen, Outi Elomaa, Juha Kere, Ulpu Saarialho-Kere
DOI: 10.2340/00015555-0184

The PSORS1 locus is the consistently replicated genetic risk factor for psoriasis. Clinical associations with the main marker allele of PSORS1, HLA-Cw6, have been addressed in a number of studies, but clinical associations have not been used as a way to distinguish the effects of the neighbouring candidate genes in PSORS1. Our results show that HLA-Cw6 and CCHCR1 risk allele associations with clinical features of psoriasis are predict­ably highly similar in a Finnish nationwide cohort of 379 psoriasis patients. The clinical profiling of a small group of patients (n=34) who were HLA-Cw6- but CCHCR1*WWCC positive suggested that no great differences existed between them and HCR-Cw6- patients. HCR+ genotype (as well as Cw6+ genotype) correlated for the first time positively with female sex and, in contrast with previous studies, negatively with disease severity. Presence of psoriatic arthritis was more pronounced in HCR- psoriasis (as well as in Cw6- psoriasis). Clinical profiling may be a useful approach to distinguishing genetic effects of candidate genes even within a locus in sufficiently large cohorts.