The CRYBB1 gene, located on 22q12.1 chromosome, encodes a beta basic group member that undergoes extensive cleavage at its N-terminal extension during lens maturation.  The latter protein is required for maintaining lens transparency and refractive index of the lens.   The CRYBB1 gene is located within a gene cluster that contains beta-A4, beta-B2, and beta-B3.  This protein is expressed prenatally in the lens tissue.  About 13 functional crystallin genes have been located in the human genome, and 11 major crystallin proteins have been isolated from the human lens.  These proteins are classified into two classes: taxon-specific, or enzyme, and ubiquitous. 

Defects in this protein are the cause of cataract 17, multiple types (CTRCT17) as well as congenital cataract and microcornea syndrome.

The CRYBB1 gene spans approximately 18 kb within the genomic DNA with five coding exons.  It encodes a protein of 252 amino acids.  Mutations in this gene have been found in patients with cataract 17, multiple types (CTRCT17) as well as congenital cataract and microcornea syndrome.