Congenital cataract-hearing loss-severe developmental delay syndrome is a rare genetic disorder characterized by the presence of congenital cataracts, hearing loss, and severe developmental delay. It is caused by a mutation in the GJB2 gene, which is responsible for the production of a protein called connexin 26. This protein is essential for the normal development of the eye and inner ear, as well as for normal brain development. Symptoms of this disorder include vision impairment, hearing loss, and severe developmental delays. Treatment typically involves the use of hearing aids, glasses, and physical and occupational therapy.