CRYAA

CRYAA is a gene that provides instructions for making a protein called alpha-crystallin A chain. This protein is a type of crystallin and is primarily found in the lens of the eye. Crystallins maintain the transparency of the lens and have other functions outside the lens. The alpha-crystallin A chain is part of a protein complex that protects other proteins from damage.

Function

The CRYAA gene belongs to the small heat shock protein (sHSP also known as the HSP20) family. This family is characterized by a common sequence of approximately 90 amino acids known as an alpha-crystallin domain. The alpha-crystallin A chain has structural and functional similarities to the small heat shock proteins.

The alpha-crystallin A chain binds to proteins that have lost their shape and functionality due to stress and prevents them from clumping together. This process is known as molecular chaperone activity.

Clinical significance

Mutations in the CRYAA gene are associated with several types of cataract, a clouding of the lens that can impair vision. These include autosomal dominant cataract, age-related cataract, and congenital cataract.

Mutations can change single amino acids in the alpha-crystallin A chain, which may disrupt the protein's structure and its ability to bind to other proteins. This can lead to the formation of protein clumps that cloud the lens, leading to cataract formation.

See also

• Crystallin
• Cataract
• Molecular chaperone