GAA Gene - Glucosidase Alpha, Acid
Gene encoding acid alpha-glucosidase, essential for glycogen degradation; mutations cause Pompe disease.
Gene Information Card
| Symbol | GAA |
|---|---|
| Full Name | Glucosidase Alpha, Acid |
| Gene Type | protein-coding |
| Chromosomal Location | 17q25.3 |
| NCBI Gene ID | 2548 ncbi.nlm.nih.gov/gene/2548 |
| Ensembl ID | ENSG00000171298 |
| UniProt ID | P10253 |
| OMIM ID | 606800 |
| HGNC ID | 4065 |
| Aliases | LYAG, acid maltase, GAA1 |
Description
The GAA gene encodes acid alpha-glucosidase (EC 3.2.1.20), a lysosomal enzyme that hydrolyzes glycogen to glucose. Deficiency of this enzyme leads to glycogen accumulation in lysosomes, causing Pompe disease (glycogen storage disease type II). The gene spans approximately 20 kb and contains 20 exons.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Pompe disease (Glycogen storage disease type II) | Loss-of-function mutations in GAA cause deficiency of acid alpha-glucosidase, leading to lysosomal glycogen accumulation in cardiac and skeletal muscle. | ClinVar, OMIM |
| Glycogen storage disease type IIb (Danon disease variant) | Not applicable; Danon disease is caused by LAMP2 mutations, not GAA. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal muscle | 12.3 | Medium |
| Heart | 9.8 | Medium |
| Liver | 6.5 | Low |
| Brain | 4.2 | Low |
| Kidney | 7.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 8.5 | nTPM from GTEx |
| HepG2 | 10.2 | nTPM from GTEx |
| K562 | 5.3 | nTPM from GTEx |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.2560C>T (p.Arg854Ter) | Nonsense | ~2% in European populations | Loss of function; associated with infantile-onset Pompe disease |
| c.2238G>A (p.Trp746Ter) | Nonsense | Rare | Loss of function; severe phenotype |
| c.1935C>A (p.Asp645Glu) | Missense | ~1% in Asian populations | Reduced enzyme activity; late-onset Pompe disease |
| c.1082C>T (p.Pro361Leu) | Missense | Rare | Partial loss of function; variable phenotype |
Mutation functional classification
Loss of Function (LOF)
Most GAA mutations cause loss of enzyme function, leading to Pompe disease.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Not applicable; GAA deficiency is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • hydrolase activity (GO:0004553) | • lysosome (GO:0005764) |
| • carbohydrate metabolic process (GO:0005975) | • glycogen catabolic process (GO:0005980) |
| • hydrolase activity (GO:0016798) |
Pathways
• Glycogen metabolism (Reactome: R-HSA-8982491)
• Lysosomal degradation (Reactome: R-HSA-6798695)
Protein Summary
Acid alpha-glucosidase (GAA) is a 952-amino-acid lysosomal enzyme that cleaves alpha-1,4 and alpha-1,6 linkages in glycogen. It is synthesized as a 110 kDa precursor, processed to 76 and 70 kDa forms. Deficiency causes Pompe disease, treatable with enzyme replacement therapy (alglucosidase alfa).
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GAA Knockout HEK293 Cell Line | EDJ-KQ4677 | Human | 2548 | Details Get a Quote |
| GAA Knockout A-549 Cell Line | EDJ-KQ27375 | Human | 2548 | Details Get a Quote |
| GAA Knockout HCT 116 Cell Line | EDJ-KQ27376 | Human | 2548 | Details Get a Quote |
| GAA Knockout HeLa Cell Line | EDJ-KQ27377 | Human | 2548 | Details Get a Quote |
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