Sialuria is a rare disorder that affects development. Infants with sialuria are often born with a yellow tint to the skin and the whites of the eyes (neonatal jaundice), an enlarged liver and spleen (hepatosplenomegaly), and unusually small red blood cells (microcytic anemia). They may develop a somewhat flat face and distinctive-looking facial features that are described as "coarse." Temporarily delayed development and weak muscle tone (hypotonia) have also been reported.

Variants (also called mutations) in the GNE gene cause sialuria. The GNE gene provides instructions for making an enzyme found in cells and tissues throughout the body. This enzyme is involved in a chemical pathway that produces sialic acid, which is a simple sugar that attaches to the ends of more complex molecules on the surface of cells. By modifying these molecules, sialic acid influences a wide variety of cellular functions, including cell movement (migration), the attachment of cells to one another (adhesion), signaling between cells, and inflammation.

Fewer than 20 cases of sialuria have been described worldwide. There are probably more people with the disorder who have not been diagnosed, as sialuria can be difficult to detect because of its variable features.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most reported cases have occurred in people with no known history of the disorder in their family. These cases may represent new (de novo) variants in the gene that occur during the formation of reproductive cells (eggs or sperm) in an affected individual's parent or during early embryonic development.

Published Date: March 06, 2024
Published By: National Institutes of Health