Alternative Name: Pompes Disease
Clinical use: Diagnosis of Acid Maltase deficiency.
Background: Acid Maltase Deficiency (AMD), also known as Pompes disease, is a genetically inherited disease that affects muscle function. Patients with AMD have a defect, or mutation, in a gene that functions in muscles, called the Acid Alpha-Glucosidase (GAA) gene. This genetic mutation causes a substance called glycogen to build up in the muscles of patients with AMD. Glycogen is a form of starch that is used to store short-term energy. Glycogen build-up in the muscles of patients with AMD causes damage to the muscles, which leads to a progressive weakening of the muscles. This glycogen build-up may weaken the muscles of the heart and respiratory system.

Cardiac or respiratory failure is the most common cause of death in patients with AMD. AMD is estimated to affect about one in 40,000 to 100,000 births. The time of onset of AMD can vary among patients and can occur in infants, children, or adults. The infant onset form is considered to be the most severe, and usually results in death within one year.

In general, the later the onset of AMD, the more slowly it will progress, and the less severe the symptoms. Children and adults diagnosed with AMD usually have a life expectancy from 10 to 20 years after symptoms begin to appear.

Reference ranges: Blood: 3 – 20 ┬Ámol/g/h
Blood Spot Card: 7.3 – 39 pmol/punch/h
Associated diseases:
Patient preparation: None required
Specimen requirements: EDTA – Whole blood sample OR a blood spot Guthrie card is required for analysis.

Make sure the form is clearly labelled ‘Acid Maltase’.

Turnaround time: 3 working weeks
Additional information: www.labtestsonline.org.uk
Referred test: Referred test
Location: Willink Unit