SLC19A2

The SLC19A2 gene provides instructions for making a protein called thiamine transporter 1. This protein is located on the surface of cells, where it works to bring vitamin B1 (thiamine) into cells. Thiamine helps the body convert carbohydrates into energy, and it is also essential for the functioning of the heart, muscles, and nervous system. This vitamin must be obtained from the diet because the body cannot produce thiamine on its own. Many different foods contain thiamine, including whole grains, pasta, fortified breads and cereals, lean meats, fish, and beans.

thiamine-responsive megaloblastic anemia syndrome - caused by mutations in the SLC19A2 gene

At least 17 mutations in the SLC19A2 gene have been found to cause thiamine-responsive megaloblastic anemia syndrome. Most of these mutations lead to the production of an abnormally short, nonfunctional thiamine transporter 1. Other mutations change single protein building blocks (amino acids) in thiamine transporter 1, which disrupts the proper folding of the protein or prevents it from reaching the cell surface. All of these mutations prevent thiamine transporter 1 from bringing thiamine into the cell.

It remains unclear how the absence of thiamine transporter 1 leads to the seemingly unrelated symptoms of megaloblastic anemia, diabetes, and hearing loss. Research suggests that an alternative method for transporting thiamine is present in all the cells of the body, except where blood cells and insulin are formed (in the bone marrow and pancreas, respectively) and cells in the inner ear.