Background: Disseminated superficial actinic porokeratosis (DSAP) is an uncommon autosomal dominant chronic disorder of keratinization, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. Thus far, although two loci for DSAP have been identified, and the genetic basis and pathogenesis of this disorder have not been elucidated.
Objectives: To determine the locus of DSAP and identify the candidate gene(s) of the disease.
Methods: Genome-wide scan and linkage analysis were performed in a six-generation Chinese family with DSAP. The coding exons of the candidate genes were sequenced to analyse and detect the nucleotide variations.
Results: Linkage analysis showed that the maximum two-point lod score of 5.56 was obtained with the marker D12S79 at a recombination fraction theta of 0.00. Haplotype analysis defined the critical region for DSAP between D12S330 and D12S1612 on 12q24.1-24.2. By sequence analysis, we found a Val591Met mutation in SART3 in all affected individuals of the family.
Conclusion: SART3 is a candidate gene for DSAP, and is possibly involved in the pathogenesis of DSAP.