Genomewide scan in German families reveals evidence for a novel psoriasis-susceptibility locus on chromosome 19p13

Psoriasis is a common chronic inflammatory: skin disease with a strong genetic component. Few psoriasis-susceptibility loci have been reported, and only two have been confirmed in independent data sets. This article reports results of a genomewide scan that was performed, using 370 microsatellite markers, for psoriasis-susceptibility loci in 32 German extended families, comprising 162 affected and 195 unaffected individuals. Nonparametric linkage analysis of all families provided strong evidence for a novel psoriasis-susceptibility locus on chromosome 19p (Z(lr) = 3.50; P = .0002). Parametric analysis revealed a heterogeneity LOD score of 4.06, corresponding to a genomewide significance level of .037, under the assumption of a recessive model with high disease-allele frequency and 66% as the proportion of linked families. This study confirms linkage of psoriasis to the HLA region on chromosome 6p and suggests additional regions on chromosomes 8q and 21q for further investigations.