Aspartylglucosaminuria

Aspartylglucosaminuria, abbreviated AGU, is an inherited disease marked by a gradual decline in mental functioning together with growing problems of the skin, bones and joints. It follows an autosomal recessive pattern, so a child is affected only after inheriting a changed gene from both parents. The cause is a defect in the enzyme aspartylglucosaminidase, which normally breaks down sugar chains such as oligosaccharides that are attached to proteins. Because the enzyme works inside lysosomes, the disease is classed as a lysosomal storage disease. When the glycoproteins are not broken down, material builds up in the lysosomes together with other substances, and this backup causes progressive damage to tissues and organs, including the liver, spleen, thyroid and nerves. This entry records what the source states about the condition and is not medical advice.