Genetics of Congenital Cataract

Congenital cataract is a type of cataract that presents at birth or during early childhood, and it is one of the most easily treatable causes of visual impairment and blindness during infancy, with an estimated prevalence of 1-6 cases per 10,000 live births. Approximately 50% of all congenital cataract cases may have a genetic cause, and such cases are quite heterogeneous. Although congenital nuclear cataract can be caused by multiple factors, genetic mutation remains the most common cause. All three types of Mendelian inheritance have been reported for cataract; however, autosomal dominant transmission seems to be the most frequent. The transparency and high refractive index of the lens are achieved by the precise architecture of fiber cells and homeostasis of the lens proteins in terms of their concentrations, stabilities, and supramolecular organization. Research on hereditary congenital cataract has led to the identification of several classes of candidate genes that encode proteins such crystallins, lens-specific connexins, aquaporin, cytoskeletal structural proteins, and developmental regulators. In this review, we highlight the identified genetic mutations that account for congenital nuclear cataract.