Dominantly and recessively inherited cornea plana congenita map to the same small region of chromosome 12.

Abstract

Cornea plana congenita occurs in a mild autosomal dominant (CNA1) and a more severe autosomal recessive (CNA2) form. We recently assigned a CNA2 locus to a region on chromosome 12 by linkage analysis and excluded linkage to that locus in two Finnish CNA1 families. Here we describe a Cuban pedigree in which 14 members are affected with dominantly inherited cornea plana. By linkage analysis this phenotype was mapped to the immediate vicinity of markers D12S82 and D12S351 on 12q, that is, precisely the same small region (3 cM or less) to which CNA2 previously had been assigned. Our results support the existence of at least three genetically distinct forms of cornea plana. It remains to be determined whether recessive and dominant cornea plana are caused by different mutations of a single gene or whether the region in 12q harbors two or more genes whose mutations cause corneal maldevelopment.