Identification of a locus for disseminated superficial actinic porokeratosis at chromosome 12q23.2-24.1

Disseminated superficial actinic porokeratosis is an autosomal dominant cut aneous disorder characterized by many uniformly small, minimal, annular, an hidrotic, and keratotic lesions. The genetic basis for this disease is unkn own. Using a genomewide search in a large Chinese family, we identified a l ocus at chromosome 12q23.2-24.1 responsible for disseminated superficial ac tinic porokeratosis. The fine mapping study indicates that the disseminated superficial actinic porokeratosis gene is located within a 9.6 cM region b etween markers D12S1727 and D12S1605, with a maximum two-point LOD score of 20.53 (theta = 0.00) at D12S78. This is the first locus identified for a g enetic disease where the major phenotype is porokeratosis. The study provid es a map location for isolation of a gene causing disseminated superficial actinic porokeratosis.