Identification of a novel partial deletion of associated with pre-Descemet corneal dystrophy and X-linked ichthyosis.

PURPOSE

Pre-Descemet corneal dystrophy (PDCD) with X-linked ichthyosis (XLI) is associated with mutations in or deletions of the steroid sulfatase gene (). As only three cases of genetically confirmed PDCD associated with XLI have been reported, we sought to expand our understanding of the genetic basis of PDCD by screening in two previously unreported families.

MATERIALS AND METHODS

The affected individuals underwent cutaneous and slit-lamp examinations. Saliva samples collected from each affected individual served as a source of DNA for the amplification of the 10 coding exons of and flanking DNA markers.

RESULTS

The slit-lamp examination of three affected men (two of whom were brothers) from two families revealed bilateral punctate posterior corneal stromal opacities anterior to the Descemet membrane. Cutaneous examination demonstrated dry, coarse, scaly ichthyotic changes characteristic of XLI in all individuals. Genetic examination of the locus on the X chromosome in Case 1 revealed a deletion that spanned across DNA markers DXS1130-DXS237, which includes all the coding exons (exons 1-10) of . Genetic screening of Cases 2 and 3 revealed a partial deletion of the locus involving exons 1-7 and flanking DNA marker DXS1130 on the X chromosome.

CONCLUSIONS

PDCD with XLI may be associated with either partial or complete deletion of . Despite the identification of point mutations, partial deletion, and complete deletion of in different affected families reported to date, there was no apparent difference in the affected phenotype between the families, suggesting that the identified variants likely all resulted in loss of function of steroid sulfatase.