GENE FOR FAMILIAL PSORIASIS SUSCEPTIBILITY MAPPED TO THE DISTAL END OF HUMAN-CHROMOSOME 17Q

A gene involved in psoriasis susceptibility was localized to the dista l region of human chromosome 17q as a result of a genome-wide linkage analysis with polymorphic microsatellites and eight multiply affected psoriasis kindreds. In the family which showed the strongest evidence for linkage, the recombination fraction between a psoriasis susceptibi lity locus and D17S784 was 0.04 with a maximum two-point lod score of 5.33. There was also evidence for genetic heterogeneity and although n one of the linked families showed any association with HLA-Cw6, two un linked families showed weak levels of association. This study demonstr ates that in some families, psoriasis susceptibility is due to variati on at a single major genetic locus other than the human lymphocyte ant igen locus.