Missense Mutations in the MIP Gene, Encoding the Major Intrinsic Protein of the Lens (Aquaporin-0), Underlie Cataracts in Humans

Abstract

Cataract is the term used to describe opacification of the crystalline lens of the eye. It is the commonest cause of adult blindness world-wide and the most frequent treatable cause of visual impairment in childhood (Lambert & Drack 1996). Childhood cataract may be inherited, usually as an autosomal dominant trait, where it is both genetically heterogeneous and phenotypically diverse (Ionides et al., 1999). Independent chromosomal loci have been mapped to 1p36, q21-25, 2q33-35, 13q, 16q22.1, 17p, 17q11-12, 17q24, 21q and 22q. Underlying mutations are now known in the crystallin genes at the loci on 2q, 21q and 22q, the connexin genes on 1q and 13q and the developmental regulator gene PITX3 on 10q (Francis et al., 1999).