Linkage of congenital hereditary endothelial dystrophy to chromosome 20

Congenital heredity endothelial dystrophy (CHED) is a rare autosomal dominant disorder of the cornea. We have performed genetic linkage analysis with microsatellite markers on a seven generation British pedigree. Two-point linkage analysis revealed significant linkage of CHED (lod score >3) with seven marker loci mapping to chromosome 20. The highest observed lod score was 7.20 (theta=0.026) with marker D20S114. Multipoint analysis gave a maximum lod score of 9.34 between D20S48 and D20S471. This 2.7cM region lies within 30 cM region recently assigned to posterior polymorphous dystrophy (PPD). PPD and CHED may therefore be allelic, or alternatively it is possible that more than one gene in this region is responsible for these two corneal dystrophies.