This test detects alpha-L-iduronidase enzyme activity that has been associated with mucopolysaccharidosis type I.

This test may be appropriate for individuals with a clinical suspicion of mucopolysaccharidosis type I and/or individuals with a family history of mucopolysaccharidosis type I.

Mucopolysaccharidosis type I is a disease associated with the accumulation of complex carbohydrates in various tissues caused by a lysosomal storage disorder. The disease is separated into severe and attenuated forms. The severe form has an age of onset in infancy and the attenuated form has an age of onset in childhood. Both forms show symptoms of a large head, hydrocephalus, distinctive facial features, hepatosplenomegaly, an enlarged tongue, umbilical and inguinal hernias, clouded corneas, hearing loss, weakness in the hands and fingers, and spinal stenosis. The severe form of the disease can also include symptoms of developmental regression, intellectual decline, rapid disease progression, and a life expectancy of late childhood. The attenuated form of the disease can include symptoms of intellectual disability and typically live into adulthood. The incidence of mucopolysaccharidosis type I is estimated to be ~ 1 in 100,000.

Tandem mass spectrometry analysis can be coupled with liquid chromatography, a technique referred to as LC-MS/MS. In this methodology, chromatography is used to separate analytes of interest prior to measurement by the mass spectrometer. This separation reduces interference from matrix components and can also allow for the measurement of analytes that have the same mass (isobaric species), thereby improving analytical specificity compared to MS/MS.