Mucopolysaccharidosis type VII (MPS VII), also called Sly syndrome, is a rare inborn error of metabolism (IEM) and autosomal recessive disorder caused by mutations in the GUSB gene. This gene encodes for the beta-glucuronidase enzyme, which normally breaks down glycosaminoglycans (GAGs). However, without beta-glucuronidase, accumulation of GAGs in cells specifically the lysosome increases. The increase in cell size causes tissues and organs to become enlarged as well. This disorder is characterized by macrocephaly, a buildup of fluid in the brain, characteristic facial features, and a large tongue. Other symptoms may include hepatosplenomegaly, heart valve abnormalities, and umbilical or inguinal hernias. MPS VII also causes various skeletal abnormalities, including joint issues and decreased growth. Treatments such as enzyme replacement therapy are still fairly new, however traditionally treatments for Mucopolysaccharidosis VII included symptom relief such as surgery. It is estimated that MPS VII affects 1 in 250,000 individuals.  

Mucopolysaccharidosis VII. Sly Syndrome References

Starch and Sucrose Metabolism References