This test detects β-glucuronidase enzyme activity that has been associated mucopolysaccharidosis type VII (MPS VII).

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

Mucopolysaccharidosis type VII is a disease associated with abnormal accumulation of complex carbohydrates in various tissues caused by a lysosomal storage disorder. Age of onset is variable with most individuals showing symptoms by early childhood. Symptoms typically include a large head, hydrocephalus, distinctive facial features, a large tongue, heart valve abnormalities, hepatosplenomegaly, umbilical or inguinal hernias, short stature, contractures, spinal stenosis, weakness of the hands and fingers, clouded corneas, sleep apnea, hearing loss, recurrent ear infections, developmental delay and progressive intellectual disabilities. Hydrops fetalis can occur during pregnancy and is typically lethal in the neonate period. Life expectancy is reduced, and in severe forms death occurs in late childhood. The incidence of mucopolysaccharidosis type VII is estimated to be ~1 in 250,000.

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.