Refinement of the localisation of the X linked keratosis follicularis spinulosa decalvans (KFSD) gene in Xp22.13-p22.2.

X-linked keratosis follicularis spinulosa decalvans (KFSD) is a rare disorder affecting the skin and eyes. The disease was previously mapped in an extended Dutch family to Xp21.2-p22.2 between DXS16 and DXS269. Using five DNA probes and 14 CA repeat polymorphisms spanning this region an extensive linkage study was performed in the same pedigree. The highest lod scores were 12.07 for DXS365 (pRX-314) at 0 = 0, 11.72 for DXS418 (P122) at 0 = 0.015, and 10.93 for DXS989 (AFM135xe7) at 0 = 0.045. Analysis of recombination events locates the gene for KFSD between AFM291wf5 and DXS1226 (AFM316yf5). This is region Xp22.13-p22.2, an area covering approximately 1 Mb. These data confirm and greatly refine the regional localisation of KFSD and greatly improve reliability of carrier detection.