SLRR gene family

Genes in the small leucine-rich repeat (SLRR) family provide instructions for making the protein component of molecules called proteoglycans. Proteoglycans are made up of a central protein attached to one or more sugar molecules. The SLRR gene family is a subset of a larger gene family known as the proteoglycan superfamily.

Small leucine-rich proteoglycans are grouped together because their central proteins all contain segments called leucine-rich repeats. These short, repeated segments contain many copies of the protein building block (amino acid) leucine. Proteoglycans in the SLRR family are found in the extracellular matrix, which is the intricate lattice of proteins and other molecules that forms in the spaces between cells.

Small leucine-rich proteoglycans have a variety of functions. They are involved in chemical signaling, interactions between proteins, the attachment of cells to one another (cell adhesion), and the regulation of cell growth and division. Small leucine-rich proteoglycans interact with a variety of growth factors, which control a diverse range of processes important for cell growth. Several members of this family help regulate the organization of proteins called collagens. Collagens strengthen and support connective tissues such as skin, tendon, bone, and cartilage.

Mutations in SLRR genes have been associated with several genetic eye disorders. DCN gene mutations cause congenital stromal corneal dystrophy, which causes the clear outer covering of the eye (the cornea) to become cloudy. Mutations in another gene, KERA, are responsible for an eye abnormality called cornea plana, in which the cornea is abnormally flattened. Mutations in several SLRR genes have also been associated with severe nearsightedness (high myopia). Each of these conditions causes a loss of sharp vision (reduced visual acuity) and related eye abnormalities.