SBF2

The SBF2 gene (also called MTMR13) provides instructions for making a protein called SET binding factor 2. The function of this protein remains unknown, but it probably plays a role in cellular communication or the signaling network that is essential for the production of myelin. Myelin is the protective substance that covers nerve cells and promotes the rapid transmission of nerve impulses. SET binding factor 2 probably also plays a role in the development of meshlike drainage canals (trabecular meshwork) that surround the colored part of the eye (the iris).

Charcot-Marie-Tooth disease - caused by mutations in the SBF2 gene

Several SBF2 mutations have been identified in patients with a form of Charcot-Marie-Tooth disease known as type 4B2. These mutations alter the structure of SET binding factor 2 by producing an abnormally small protein or a protein that is missing a critical segment. The altered structure probably causes a loss of the protein's function. Although it remains unclear how SBF2 mutations lead to this disorder, the signaling network necessary for myelin production is probably disrupted. Irregular myelin structure (called outfolding) is a characteristic sign of type 4B2 Charcot-Marie-Tooth disease.

Individuals with this disorder may also experience a buildup of pressure within the eye (glaucoma) beginning in childhood or adolescence. Researchers believe that the appearance of glaucoma depends on the type of SBF2 mutation. A mutation that causes complete loss of protein function leads to glaucoma. Less severe mutations, which allow partial function of the SET binding factor 2 protein, do not cause glaucoma.