Genetics & Epidemiology
Pompe disease is an autosomal recessive genetic disorder that affects both sexes equally. Pompe disease is rare and its incidence is estimated at approximately 1 in 40,000 live births. While the disease is pan-ethnic, it may be more prevalent in certain populations., 
Pompe disease is caused by mutations in the gene that encodes for the enzyme acid alpha-glucosidase (often abbreviated as GAA), responsible for metabolizing glycogen in lysosomes. In 1979 this gene was traced to chromosome 17 (location 17q25.2-q25.3) and designated GAA on the human genome map., 
Read details of Pompe disease incidence and prevalence
Find out more about the various GAA gene mutations
Mode of Inheritance
As an autosomal recessive disorder, Pompe disease is inherited when a person receives a copy of a mutated GAA gene from each parent. Individuals with one mutated gene and one normal gene are considered carriers and are unaffected by the disease.
The following diagram illustrates the odds of two carrier parents passing the disease onto their children:
Each child born to two carrier parents has a:
25% chance of inheriting Pompe disease
50% chance of being a carrier
25% chance of being completely unaffected
There are other less common scenarios:
- If one parent has Pompe disease and the other parent is unaffected, all children will be carriers, but none will develop the disease.
- In the very rare case where one parent has the disease and the other is a carrier, each child will have a 50% chance of inheriting the disease and a 50% chance of being a carrier.
Status of Carriers
Carriers of Pompe disease are phenotypically normal, since one normal copy of the GAA gene produces enough enzyme activity to prevent the excessive lysosomal deposition of glycogen. Compared to unaffected individuals, however, carriers do usually display lower-than-normal enzyme activity.
Ausems MG, Verbiest J, Hermans MP, et al. Frequency of glycogen storage disease type II in The Netherlands: implications for diagnosis and genetic counseling. Eur J Hum Genet 1999 Sep; 7(6): 713-6.
Martiniuk F, Chen A, Mack A, et al. Carrier frequency for glycogen storage disease type II in New York and estimates of affected individuals born with the disease. Am J Med Genet 1998;79:69-72.
D’Ancona GG, Wurm J, Croce CM. Genetics of type II glycogenosis: assignment of the human gene for acid alpha-glucosidase to chromosome 17. Proc Natl Acad Sci U S A 1979; 76:4526-9.
Hirschhorn, Rochelle and Arnold J. J. Reuser. Glycogen Storage Disease Type II: Acid Alpha-Glucosidase (Acid Maltase) Deficiency. In: Scriver C, Beaudet A, Sly W, Valle D, editors. The Metabolic and Molecular Bases of Inherited Disease. 8th Edition. New York: McGraw-Hill; 2001; 3389-3420.
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