The gene for a rare autosomal dominant form of pompholyx maps to chromosome 18q22.1-18q22.3.

Pompholyx is a rather common disorder characterized by recurrent crops of vesicles or bullae on the lateral aspects of the fingers, as well as the palms and soles with non-erythematous skin. Until now, very few large families have been reported, so no gene or locus has been identified. Here, we performed a genome-wide search in a large Chinese family to map the chromosome location of the responsible gene. We identified a locus at chromosome 18q22.1-18q22.3 with a maximum two-point LOD score of 3.61 at marker D18S1131 (theta = 0.00). Haplotype analyses indicated that the disease gene is located within 12.07 cM region between markers D18S465 and D18S1362, which corresponds to 8.0 Mb. This is the first locus identified for pompholyx. It will aid future identification of the responsible gene, which will be useful for the understanding of the molecular mechanism of pompholyx.