Hurler syndrome
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 (GAGs) 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.
| Hurler syndrome | |
|---|---|
| Patient with Hurler syndrome | |
| Causes | Deficiency of the alpha-L iduronidase enzyme |
| Differential diagnosis | Hurler-Scheie syndrome; Scheie syndrome; Hunter syndrome; other mucopolysaccharidoses |
| Prognosis | Death usually occurs before 12 years |
| Frequency | 1 in 100,000 |
The underlying mechanism is a deficiency of alpha-L iduronidase, an enzyme responsible for breaking down GAGs.: 544 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.