Molecular genetic analysis of two families with keratosis follicularis spinulosa decalvans: refinement of gene localization and evidence for genetic heterogeneity

Abstract

X-linked keratosis follicularis spinulosa decalvans (KFSD) is a rare disorder affecting both skin and eyes. In the two extended KFSD families analysed to date, the gene was mapped to Xp22.13–p22.2. By analyzing several new markers in this region, we were able to narrow the candidate region to a 1-Mb interval between DXS7161 and (DXS7593, DXS7105) in the large Dutch pedigree. In addition, we analyzed 23 markers in Xp21.2– p22.2 in a German family with KFSD. Haplotype and recombination analysis positioned the KFSD gene in this family most likely outside the candidate region on Xp22.13–p22.2. This finding is suggestive for genetic heterogeneity: in this pedigree there is either another locus on the X-chromosome, or KFSD is transmitted here as an autosomal dominant trait with variable expression.