Hurler syndrome, also known as mucopolysaccharidosis Type IH (MPS-IH), Hurler's disease, and formerly gargoylism, is a genetic disorder that results in the buildup of large sugar molecules called glycosaminoglycans (AKA GAGs, or mucopolysaccharides) in lysosomes. The inability to break down these molecules results in a wide variety of symptoms caused by damage to several different organ systems, including but not limited to the nervous system, skeletal system, eyes, and heart.
The underlying mechanism is a deficiency of alpha-L iduronidase, an enzyme responsible breaking down GAGs. Without this enzyme, a buildup of dermatan sulfate and heparan sulfate occurs in the body. Symptoms appear during childhood, and early death usually occurs. Other, less severe forms of MPS Type I include Hurler-Scheie Syndrome (MPS-IHS) and Scheie Syndrome (MPS-IS).
Hurler syndrome is classified as a lysosomal storage disease. It is clinically related to Hunter syndrome (MPS II); however, Hunter syndrome is X-linked, while Hurler syndrome is autosomal recessive.