Analysis of three suggested psoriasis susceptibility loci in a large Swedish set of families: Confirmation of linkage to chromosome 6p (HLA region), and to 17q, but not to 4q

Psoriasis is known to be a heterogeneous disease with so far three reported major psoriasis susceptibility loci on chromosome 4q, 6p and 17q. In this study we investigated three reported gene locations by nonparametric and pa rametric linkage analysis in a large family set consisting of 104 families (153 sib pairs) from Sweden. We could confirm linkage to chromosome 6p. A m aximum heterogeneous lod score of 2.78 was reached at locus D6S276 (a = 0.6 0). Allelic association studies within the HLA region indicated linkage dis equilibrium at locus TNF beta with a significant p value of 0.0009. Further more, we obtained weak evidence of linkage to the locus on chromosome 17q w hile no evidence of linkage could be found to the chromosome 4q region.