Objective: This project, Clinical and Molecular Studies in Families with Congenital or Hereditary Cataracts will study the inheritance of genetic cataracts, both Mendelian and complex age related cataracts, in families of many nationalities and ethnic backgrounds in order to identify the genes that, when mutated, cause cataracts and the pathophysiology through which they act.

Study Population: Families of many nationalities and ethnic backgrounds. We will study a maximum or 5,000 patients and family members.

Design: The study consists of ascertaining individuals, and especially families with multiple individuals, affected by both congenital and age related cataracts. These patients and their families will undergo detailed ophthalmological examinations to characterize their cataracts and determine their affectation status. A blood sample will be collected from each individual for isolation of DNA and in some individuals for lymphoblastoid transformation to establish a renewable source of DNA. Linkage analysis, physical mapping, and mutational screening will be carried out to identify the specific the gene and the mutations in it that are associated with cataracts in this family. If necessary, the gene product will be characterized biochemically. The study will enroll subjects at NEI and collaborating institutions, the Centre for Excellence in Molecular Biology, Lahore, Pakistan, the Zhongshan Ophthalmic Center, Guangzhou, China, the Aravind Eye Hospital, Madurai, India, and the University of Parma, Italy.

Outcome Measures: Linkage will be determined using the lod score method and mutations in specific genes will be assessed using a combination of residue conservation, blosum score, and molecular modeling. Biochemical, metabolic, and physiological effects will be individualized to the specific assay.