Psoriasis susceptibility locus in chromosome region 3q21 identified in patients from southwest Sweden

We have performed a pair-wise linkage study in the search for psoriasis sus ceptibility regions. a preliminary scan was performed on 20 families. In th is set we obtained indications of linkage on chromosome 3q21, This region w as further investigated using material from a total of 104 families (set 1B ) resulting in a non-parametric linkage (NPL) of 1.77, The material was str atified in families whose parental origin is in southwest Sweden (set 1C), A maximum NPL value of 2.77 was obtained in this group. A transmission dise quilibrium test (TDT) was performed on the stratified material (set 1C) ran d a significant P value of 0.005 was obtained, rat marker D3S1269, The locu s was confirmed with TDT in replicate material consisting of 148 families i n which a single member was affected (P value 0.0007) at marker D3S1551, Th us, we have observed a significant P value using TDT in the vicinity of mar kers D3S1269/D3S1551, suggesting a novel psoriasis susceptibility region.