Acid alpha-glucosidase, also called acid maltase,^[5] is an enzyme that helps to break down glycogen in the lysosome. It is functionally similar to glycogen debranching enzyme, but is on a different chromosome, processed differently by the cell and is located in the lysosome rather than the cytosol.^[6] In humans, it is encoded by the GAA gene.^[5] Errors in this gene cause glycogen storage disease type II (Pompe disease).

Quick Facts GAA, Identifiers ...

GAA
Identifiers
Aliases	GAA, LYAG, glucosidase alpha, acid, alpha glucosidase
External IDs	OMIM: 606800 MGI: 95609 HomoloGene: 37268 GeneCards: GAA
Gene location (Human) Chr. Chromosome 17 (human)[1] Band 17q25.3 Start 80,101,556 bp[1] End 80,119,881 bp[1]
Gene location (Mouse) Chr. Chromosome 11 (mouse)[2] Band 11 E2|11 83.35 cM Start 119,158,713 bp[2] End 119,176,280 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right uterine tube monocyte anterior pituitary right lung spleen upper lobe of left lung gastric mucosa stromal cell of endometrium right lobe of thyroid gland minor salivary glands Top expressed in arcuate nucleus paraventricular nucleus of hypothalamus median eminence dorsomedial hypothalamic nucleus ventromedial nucleus suprachiasmatic nucleus supraoptic nucleus entorhinal cortex lateral hypothalamus ventral tegmental area More reference expression data BioGPS More reference expression data
Gene ontology Molecular function hydrolase activity, hydrolyzing O-glycosyl compounds hydrolase activity, acting on glycosyl bonds maltose alpha-glucosidase activity catalytic activity hydrolase activity carbohydrate binding oligo-1,6-glucosidase activity alpha-1,4-glucosidase activity alpha-glucosidase activity Cellular component membrane lysosomal membrane lysosomal lumen lysosome extracellular exosome plasma membrane azurophil granule membrane tertiary granule membrane ficolin-1-rich granule membrane integral component of membrane Biological process vacuolar sequestering cardiac muscle contraction muscle cell cellular homeostasis neuromuscular process controlling posture locomotory behavior neuromuscular process controlling balance regulation of the force of heart contraction diaphragm contraction heart morphogenesis maltose metabolic process glycogen catabolic process sucrose metabolic process tissue development glycogen metabolic process metabolism lysosome organization striated muscle contraction glucose metabolic process neutrophil degranulation carbohydrate metabolic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 2548 14387 Ensembl ENSG00000171298 ENSMUSG00000025579 UniProt P10253 P70699 RefSeq (mRNA) NM_000152 NM_001079803 NM_001079804 NM_001159324 NM_008064 RefSeq (protein) NP_000143 NP_001073271 NP_001073272 NP_001152796 NP_032090 Location (UCSC) Chr 17: 80.1 – 80.12 Mb Chr 11: 119.16 – 119.18 Mb PubMed search [3] [4]
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This gene encodes lysosomal alpha-glucosidase, which is essential for the degradation of glycogen to glucose in lysosomes. Different forms of acid alpha-glucosidase are obtained by proteolytic processing. Defects in this gene are the cause of glycogen storage disease II, also known as Pompe disease, which is an autosomal recessive disorder with a broad clinical spectrum. Three transcript variants encoding the same protein have been found for this gene.^[5]