So while Pompe disease is rare in the population as a whole, close relatives of a person with Pompe disease are far more likely than the average person to have the condition themselves or be a carrier of it (see ‘Inheriting Pompe disease’ section). It is therefore very important to test family members of a person with Pompe disease, because early diagnosis is a key part of treating and managing the condition effectively.
Identifying affected family members
Measuring a person’s GAA is the standard test for Pompe disease, as GAA is lower than normal in those with the condition (see ‘Confirming the diagnosis’ section). This test can be done with just a tiny drop of blood, so it’s ideal for screening family members of a person with Pompe disease, including newborn infants.
A blood test called ‘mutation analysis’ may also be used to confirm that a person has Pompe disease. Instead of measuring GAA, this method – also called ‘genotyping’ – uses a blood sample to see if a person has the gene defect that causes the condition. This is especially useful within families, to identify ‘carriers’ of Pompe disease, as carriers have no symptoms and normal or near normal levels of GAA (see ‘Inheriting Pompe disease’ section).
When one person in a family has Pompe disease, other family members may be affected too, by having the disease themselves or being ‘carriers’ of it (see ‘Inheriting Pompe disease’ section). This can raise many troubling questions, such as who to test, how to cope with positive test results and whether future children could be affected. Happily, help is at hand in the form of ‘genetic counselors’. These specially trained healthcare professionals provide ongoing support by:
- Explaining how Pompe disease is passed down through families
- Providing balanced information on genetic testing for Pompe disease
- Helping to identify family members ‘at-risk’ of Pompe disease
- Providing practical and emotional support when a diagnosis of Pompe disease is confirmed
- Advising on family planning issues relating to Pompe disease
If you would like the help of a genetic counselor, ask your family doctor or Pompe disease specialist for information on your local genetic counseling service.