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GAA gene

alpha glucosidase

Normal Function

The GAA gene provides instructions for producing an enzyme called acid alpha-glucosidase (also known as acid maltase). This enzyme is active in lysosomes, which are structures that serve as recycling centers within cells. Lysosomes use digestive enzymes to break down complex molecules into simpler ones that can be used by cells. Acid alpha-glucosidase normally breaks down a complex sugar called glycogen into a simpler sugar called glucose. Glucose is the main energy source for most cells.

Health Conditions Related to Genetic Changes

Pompe disease

More than 200 mutations in the GAA gene have been identified in people with Pompe disease. Many of these mutations change one of the protein building blocks (amino acids) used to make acid alpha-glucosidase. Other mutations insert or delete genetic material in the GAA gene. Mutations in this gene significantly reduce the activity of acid alpha-glucosidase, preventing the enzyme from breaking down glycogen effectively. As a result, this complex sugar can build up to toxic levels in lysosomes. The abnormal buildup of glycogen damages organs and tissues throughout the body, particularly the muscles, leading to progressive muscle weakness, heart problems, and the other features of Pompe disease.

More About This Health Condition

Other Names for This Gene

  • acid alpha-glucosidase
  • acid alpha-glucosidase preproprotein
  • acid maltase
  • Aglucosidase alfa
  • Alpha-1,4-glucosidase
  • Amyloglucosidase
  • Glucoamylase
  • glucosidase, alpha; acid
  • glucosidase, alpha; acid (Pompe disease, glycogen storage disease type II)
  • LYAG
  • lysosomal alpha-glucosidase

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Fukuda T, Roberts A, Plotz PH, Raben N. Acid alpha-glucosidase deficiency (Pompe disease). Curr Neurol Neurosci Rep. 2007 Jan;7(1):71-7. doi: 10.1007/s11910-007-0024-4. Citation on PubMed
  • Hoefsloot LH, Hoogeveen-Westerveld M, Reuser AJ, Oostra BA. Characterization of the human lysosomal alpha-glucosidase gene. Biochem J. 1990 Dec 1;272(2):493-7. doi: 10.1042/bj2720493. Citation on PubMed or Free article on PubMed Central
  • Montalvo AL, Bembi B, Donnarumma M, Filocamo M, Parenti G, Rossi M, Merlini L, Buratti E, De Filippi P, Dardis A, Stroppiano M, Ciana G, Pittis MG. Mutation profile of the GAA gene in 40 Italian patients with late onset glycogen storage disease type II. Hum Mutat. 2006 Oct;27(10):999-1006. doi: 10.1002/humu.20374. Citation on PubMed
  • Moreland RJ, Jin X, Zhang XK, Decker RW, Albee KL, Lee KL, Cauthron RD, Brewer K, Edmunds T, Canfield WM. Lysosomal acid alpha-glucosidase consists of four different peptides processed from a single chain precursor. J Biol Chem. 2005 Feb 25;280(8):6780-91. doi: 10.1074/jbc.M404008200. Epub 2004 Nov 1. Citation on PubMed
  • Oba-Shinjo SM, da Silva R, Andrade FG, Palmer RE, Pomponio RJ, Ciociola KM, S Carvalho M, Gutierrez PS, Porta G, Marrone CD, Munoz V, Grzesiuk AK, Llerena JC Jr, Berditchevsky CR, Sobreira C, Horovitz D, Hatem TP, Frota ER, Pecchini R, Kouyoumdjian JA, Werneck L, Amado VM, Camelo JS Jr, Mattaliano RJ, Marie SK. Pompe disease in a Brazilian series: clinical and molecular analyses with identification of nine new mutations. J Neurol. 2009 Nov;256(11):1881-90. doi: 10.1007/s00415-009-5219-y. Epub 2009 Jul 9. Citation on PubMed
  • van der Ploeg AT, Reuser AJ. Pompe's disease. Lancet. 2008 Oct 11;372(9646):1342-53. doi: 10.1016/S0140-6736(08)61555-X. Citation on PubMed
  • Yan B, Raben N, Plotz P. The human acid alpha-glucosidase gene is a novel target of the Notch-1/Hes-1 signaling pathway. J Biol Chem. 2002 Aug 16;277(33):29760-4. doi: 10.1074/jbc.M204721200. Epub 2002 Jun 13. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.