Hurler syndrome, also known as mucopolysaccharidosis type II (MPS II), is a genetic disorder characterized by the buildup of large sugar molecules in body tissues which is caused by the lack of lysosomal enzyme. The symptoms include skeleton, heart, and respiratory abnormalities. The symptoms are similar with MPS I, the difference is that corneal clouding does not manifest in MPS II. Such abnormalities are not apparent at birth and may initially manifest as abdominal hernias, colds, and ear infections. Severe cases are often diagnosed from 18 to 36 months of age while milder cases are diagnosed from four to eight years old.
This syndrome is an X-linked genetic disorder; when females inherit the disorder, their other X chromosome can compensate for the mutant allele. Since males only have one X chromosome, it is more likely for them to be affected. This condition was first described by Charles A. Hunter in 1917.