How Is Pompe Disease Diagnosed?

Diagnosing Pompe disease can be challenging because many of the symptoms are similar to those of other diseases. In addition, symptoms often develop slowly and may not show up at the same time.

In most cases, health care providers have to rule out other more common possible causes before considering a diagnosis of Pompe disease. It may be easier to diagnose the infantile-onset form of Pompe disease because the rapid progression and more pronounced symptoms may prompt health care providers to perform more extensive testing. Older patients may initially complain of muscle weakness, fatigue, or breathing problems, which can be symptoms of other disorders

Late-onset cases tend to be more challenging to diagnose, and the road to an accurate or definitive diagnosis can be frustrating. Not only do the number, severity, and type of symptoms a patient experiences vary widely, but also the symptoms may suggest more common disorders, such as the different types of muscular dystrophy.

Given how rare the disease is, many physicians may not have encountered a patient with Pompe disease before. Because of this, physicians may need to first rule out other possible causes before beginning to consider a disorder as rare as Pompe disease.

If a patient reports only breathing problems or muscle weakness - Pompe disease may be overlooked and the patient may receive another diagnosis, such as limb-girdle, spinal muscular atrophy I, or Becker/Duchenne muscular dystrophy.

Learn more about diseases often confused with Pompe >

Medical specialists who assist in diagnosing Pompe disease

Depending on each patient's initial symptoms, the final diagnosis may be made by physicians from several fields of medicine.

For example, a 1999 study in The Netherlands found that pediatricians were responsible for diagnosing 71% of infantile-onset cases, while neurologists were responsible for diagnosing 80% of late-onset cases. In some cases, physicians may choose to refer patients to a specialist who has more experience with genetic disorders and who can perform advanced laboratory tests to confirm the diagnosis.

The infantile-onset diagnostic team may include:

Pediatric cardiologists

Pediatric neurologists

Geneticists

Metabolic specialists

The late-onset diagnostic team may include:

Neurologists

Pulmonologists

Physiatrists

A conclusive diagnosis of Pompe disease generally requires an enzyme assay test that demonstrates that the patient has deficient enzyme (acid alpha-glucosidase, "GAA") activity. This is determined by performing tests on a tissue (muscle, skin) or blood sample to verify that the patient's GAA enzyme activity is low or absent. Infantile-onset patients generally display less than 1% of the normal enzyme activity levels in skin cells; late-onset patients generally display less than 40% of the normal enzyme activity levels in skin cells.

Learn more about Laboratory Tests that are involved with diagnosing and managing Pompe disease >

Thanks to advances in technology, prenatal screening is also available for parents who think they may be carriers of Pompe disease or who become pregnant following the diagnosis of the disease in one of their other children. Those families affected by Pompe disease - including patients who are diagnosed as adults - may want to consult with a genetic counselor to discuss issues of genetic inheritance and family planning.

Learn more about Prenatal Screening >