Genetic and segregation analysis of congenital cataract in the Indian population.

Congenital cataract is a major cause of blindness in children, and there is wide variation in the few reports available on the frequencies of its different inheritance patterns. Two hundred and fifty-two families with congenital cataract belonging to 13 different states of India, were clinically and genetically investigated to study their inheritance and segregation patterns. Twenty-one percent of the cases were autosomal recessive, 15% autosomal dominant, 63% were simplex cases, and in the remaining cases the inheritance pattern was not clear. A high incidence of consanguinity (50.9%) was observed in autosomal recessive cases. Out of 340 affected individuals, 222 (65.3%) were males and 118 (34.7%) were females. Segregation analysis showed good agreement in autosomal dominant and recessive families and the data are indicative of the prevalence rate for different inheritance patterns of congenital cataract within the Indian population.