Testing for Hunter Syndrome
It may take a while to get an appointment with a medical geneticist or genetic counselor, but don't get discouraged. In order to find the cause of your or your child's symptoms, testing needs to be done, and sometimes it can take time.
Initial screening
The most commonly used laboratory screening test for an MPS disorder is a urine test for GAG. It is important to note that the urine test for GAG can occasionally be normal and yet the child still may have an MPS disorder.
Definitive diagnosis
A definitive diagnosis of Hunter syndrome is made by measuring iduronate-2-sulfatase (I2S) activity. This can be done by taking blood and testing the I2S activity in serum or white blood cells, or by taking a skin biopsy and testing the I2S activity in skin fibroblasts. In some people with Hunter syndrome, analysis of the I2S gene can determine clinical severity.
Prenatal diagnosis
If you have a child with Hunter syndrome or have a family history of it, prenatal diagnosis is available by measuring I2S enzymatic activity in amniotic fluid (a sample of the fluid that surrounds the baby in utero) or in chorionic villus (placental) tissue. Prenatal diagnosis is also available via mutation analysis.