AUTOSOMAL-DOMINANT ZONULAR CATARACT WITH SUTURAL OPACITIES IN A 4-GENERATION FAMILY

PURPOSE: We identified and examined four generations of a family with coexisting autosomal dominant zonular cataracts and sutural opacities and sought to determine their genetic basis. METHODS: Twenty-four of t he 48 members in the family were examined, Systemic and ocular histori es were obtained, and a detailed ophthalmic examination was performed, From each individual, 20 mi of blood was drawn for linkage studies wi th microsatellite markers in regions to which zonular cataracts had pr eviously been localized (chromosomes 1, 2, and 16). RESULTS: Individua ls of the first generation were reportedly asymptomatic, Several membe rs of the second generation had morphologically identical zonular cata racts, Affected members of the third generation showed morphologic het erogeneity, with the zonular opacity varying from a uniform lamella to a segregation of dots, A high degree of consanguinity in the second g eneration suggested recessive inheritance with a pseudodominant inheri tance pattern, However, examination of one member of the asymptomatic first generation disclosed senile cataractous changes superimposed on a faint zonular cataract enclosing sutural opacities and a pulverulent fetal nucleus, The latter findings were reconfirmed to be present in affected members of all generations, suggesting an autosomal dominant mode of inheritance, Initial efforts at linkage analysis excluded the gene locus causing this cataract from the Duffy, haptoglobin, and gamm a-crystallin regions. CONCLUSIONS: The cataract in this family is both phenotypically and genetically distinct from previously described and mapped cataracts.