Diagnosis & testing

Before a diagnosis is made, patients may see several specialists, since some of the early signs and symptoms of MPS I are commonly seen in many children. Because MPS I is a rare disease, physicians may not consider MPS I as a diagnosis.

To diagnose MPS I, a doctor will typically first do a urine test to look for abnormally high levels of glycosaminoglycans (GAGs). The results are compared to known reference ranges for various ages. Most individuals with MPS I have GAG levels in their urine that are higher than those of individuals without MPS I.

A urine test is only one of the first steps in diagnosing MPS I; definitive diagnosis requires a test to measure enzyme activity levels in the blood or skin cells. In healthy individuals, the tests show white blood cells, serum, and skin cells that contain normal enzyme activity. In individuals with MPS I, the enzyme activity is much lower or absent. In addition, DNA testing can be used to support a diagnosis. DNA testing can detect the specific genetic changes that code for the missing enzyme.

Earlier diagnosis may lead to earlier management of MPS I.

Family screening

Because MPS I is an inherited disorder, family screening is extremely important. One diagnosis of MPS I may uncover other affected siblings within a family.

A genetic counselor can be a valuable resource to help you understand how MPS I is inherited in families. A genetic counselor may also provide guidance to families for diagnostic, medical, and support services. For more information about genetic counseling, visit the National Society of Genetic Counselors website.

Did You Know?

May 15th is International MPS Awareness Day. Join Sanofi Genzyme as we support raising awareness of MPS disease disorders and honoring the individuals and families who are affected.