Hurler and Hunter Syndromes

Hurler Syndrome and Hunter Syndrome are the lysosomal storage diseases known as the mucopolysaccharidoses.

Hurler syndrome, also called mucopolysaccharidosis type I (MPS I), is caused by a deficiency of alpha-L-iduronidase. Similarly Hunter syndrome, also called mucopolysaccharidosis type II (MPSII), is caused by a deficiency of iduronate-2-sulfatase (I2S). In both diseases, the mutations lead to the accumulation of dermatan sulfate and heparan sulfate, leading to a variety of clinical findings.

Hunter syndrome is generally less severe than Hurler syndrome, and can be clinically differentiated by a lack of corneal clouding but with the additional finding of aggressive behavior. Hurler syndrome was formerly known as gargoylism, as build-up of mucopolysaccharide leads to the coarsening of facial features.

Find Hunter and Hurler Syndromes and more Lysosomal Storage Diseases among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.