Abstract
Purpose: :
We report a family associating an asymptomatic central keratoconus and a posterior polymorphous dystrophy. These familial cases validate the existence of a genetic link between these two clinically distinct corneal dystrophies.
Methods: :
After the discovery in an asymptomatic female patient during a screening prior to refractive surgery of a corneal topography compatible with a central keratoconus and focal vesicular endothelial lesions corresponding to a posterior polymorphous dystrophy, we conduct systematic topographies and slitlamp exams on four generations of the patient family.
Results: :
The great grandmother, grandmother and the patient’s sister are carriers of a central keratoconus and also of a posterior polymorphous dystrophy. All of them are asymptomatic. The keratoconus documented by topography is bilateral, central and sub-clinical in the four women. The vesicular endothelial lesions are focal and unilateral in two cases. The next generation doesn’t show till now any morphological corneal abnormalities.
Conclusions: :
We report about a familial association between central keratoconus and posterior polymorphous dystrophy, confirming the close genetic links between these two dystrophies. It is to our knowledge the third reported series of cases involving a familial association of a keratoconus and a posterior polymorphous dystrophy. The rarity of this association and the accessibility to four generations of carriers provides an exceptional opportunity for a genetic study. In fact, posterior polymorphous dystrophy is being approached as an allelic variant of keratoconus in the case of mutations identified in the gene VSX-1 (chromosome 20p11.2-20q11.2).
Keywords: cornea: endothelium • cornea: clinical science • genetics