Learning About Pompe
Forms of Pompe
Inheriting Pompe
Diagnosing PompeHow Do You Get Pompe Disease?
Pompe disease is an inherited condition, meaning it is passed from parent to child through the genes. The genes are made from DNA, the chemical material that contains the instructions for every process in the human body and every other feature that makes us unique.
Pompe disease is an autosomal recessive disorder.
Our genes are arranged on 23 pairs of chromosomes. One of those pairs (called sex chromosomes) determines whether a person will be male or female. The other 22 pairs (called autosomes) determine traits that are not related to a person’s sex, such as eye color and height. Pompe disease is inherited through a gene that is carried on one of the 22 pairs of autosomes. It is called a recessive disorder because you will only get it if you receive two copies of the defective GAA gene—one from each parent.
Some genes contain codes for making the enzymes that help the body function.
If there is a mutation, or change, in a gene responsible for making a specific enzyme, then that enzyme may not work properly or may not be made. People with Pompe disease inherit an abnormal gene from both of their parents that interferes with the production of the enzyme called acid alpha-glucosidase (GAA). GAA is responsible for breaking down lysosomal glycogen.
In most cases of Pompe disease, individuals are unable to make enough of the GAA enzyme. Others may produce normal amounts of the enzyme, but the GAA does not function as it should.
Known Pompe mutations can be identified using genotype testing, which examines the DNA in a blood sample. This is sometimes done when Pompe disease is suspected or when a presumed diagnoses has been made but not confirmed, and may also be done when there is a family history of Pompe disease.
Inheriting the gene
The chart below shows what can happen if both parents are carriers of the defective gene. With each pregnancy, there is a 25% (or 1 in 4) chance that each child will develop Pompe disease.
Other possible situations:
- If one parent has Pompe disease and the other is not a carrier, then all children will be carriers (and none will develop the disease)
- If one parent has Pompe disease and the other is a carrier (a very rare situation), then there is a 50% chance of having a child who will develop the disease and a 50% chance of having a child who is a carrier
