The differential diagnosis of a hereditary congenital cataract includes (1) Prenatal causes including virus or other infectious disease; this is more common in developing countries. Rubella directly involves the lens, whereas other infectious agents (toxoplasmosis, mumps, measles, influenza, chickenpox,herpes simplex, herpes zoster, cytomegalovirus, and echovirus type 3) result in ocular inflammation (uveitis). Depending on the clinical setting, these can be screened for by a variety of cultures and other tests including TORCH (toxoplasmosis, other agents, rubella, cytomegalovirus, herpes simplex) titers.(2) Developmental abnormalities associated with prematurity. These may be associated with low birth weight, birth anoxia, or central nervous system involvement leading to seizures, cerebral palsy or hemiplegia, and retinopathy of prematurity. (3) Perinatal-postnatal problems, such as hyperglycemia and hypocalcemia, can cause cataracts. These are associated with signs of diabetes and tetany, respectively, and can be screened for by serum chemistries. (4)Association with other ocular abnormalities, including anterior chamber abnormalities (eg, Reiger syndrome or anomaly, primary hyperplastic vitreous, aniridia,retinopathies such as retinal dysplasia, Norrie disease, and microphthalmia).(5) Association with multisystem syndromes may be suggested by the results of clinical examination, chromosome analysis, and specific blood and urine chemistries, determined by which syndromes are suspected.