Identification of a novel CRYAB mutation associated with autosomal recessive juvenile cataract in a Saudi family.

PURPOSE: To describe the first cataract-causing recessive mutation in the crystalline, alpha-b gene CRYAB.

METHODS: Homozygosity mapping complemented by linkage analysis was performed in a family with autosomal recessive juvenile cataract.

RESULTS: A homozygous missense mutation in CRYAB was identified. The mutation replaces a highly conserved amino acid residue in a dual function domain of the protein. None of the patients has clinically significant myopathy, but the oldest patient (the mother) has retinal pathology.

CONCLUSIONS: This is the first report of a recessive mutation in CRYAB causing cataract. Based on recent knowledge of the structure and function of this small heat shock protein, we speculate on the potential mutational mechanism.