solute carrier family 52 member 3
The SLC52A3 gene (previously called the C20orf54 gene) provides instructions for making a riboflavin transporter protein called RFVT3 (formerly known as RFT2). This protein moves (transports) a vitamin called riboflavin (also called vitamin B2) across the cell membrane. Riboflavin cannot be made by the body, so it must be obtained from the food a person eats. The RFVT3 protein is found at especially high levels in cells of the small intestine and is important for absorbing riboflavin during digestion so that the vitamin can be used in the body.
In the cells of the body, riboflavin is the core component of molecules called flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). These molecules function as coenzymes, which means they help enzymes carry out chemical reactions. FAD and FMN are involved in many different chemical reactions and are required for a variety of cellular processes. One important role of these coenzymes is in the production of energy for cells. FAD and FMN are also involved in the breakdown (metabolism) of carbohydrates, fats, and proteins.
More than two dozen mutations in the SLC52A3 gene have been found to cause riboflavin transporter deficiency neuronopathy. This neurological condition encompasses two disorders that were previously considered to be separate: Brown-Vialetto-Van Laere syndrome and Fazio-Londe disease. The gene mutations involved in this condition lead to production of abnormal RFVT3 proteins. Some mutations lead to the production of an altered protein that cannot get to the cell membrane, so it is unable to transport riboflavin into the cell. Other mutations lead to a version of the protein that can get to the cell membrane, but its function as a transporter is impaired. These changes impair the absorption of riboflavin in the small intestine. The resulting shortage of riboflavin leads to a reduction of FAD and FMN. However, it is unclear how these changes lead to the nerve problems that cause hearing loss, muscle weakness in the face and limbs, and breathing problems in people with the disorder.
- riboflavin transporter 2
- solute carrier family 52 (riboflavin transporter), member 3
- solute carrier family 52, riboflavin transporter, member 3