Clinical classification of autosomal dominant cataract

Purpose: To review patients with autosomal dominant cataract in order to characterise the phenotypes and to undertake genetic linkage analysis. Methods: A full ophthalmological examination was performed and blood samples were taken from the patients for DNA extraction. Candidate regions involving the areas of the human genome important in the development of cataract have initially been screened using microsatellite markers. Results: 170 patients from 22 different pedigrees were reviewed. All cataract morphologies could be classified as one of eight different phenotypes including anterior polar, posterior polar, lamellar, nuclear, coralliform, cortical, blue-dot and pulverulent. With the exception of pulverulent cataract the phenotypes show little intrafamilial variation. The phenotypes will be described and illustrated and a clinical classification of autosomal dominant cataract proposed. Conclusions: Preliminary linkage studies have excluded the seven known loci for autosomal dominant cataract in several of our pedigrees showing there are many more loci involved in autosomal dominant cataract.