GAA Gene and Pompe Disease: Mutations and Clinical Trials
The GAA gene sits on chromosome 17q25.3, and its full name is alpha glucosidase. Orphanet links GAA to 2 rare conditions and lists variants in the gene as a cause of all of them. Trial Friend's Pompe Disease and Glycogen Storage Disease Type II pages list GAA among the genes behind each condition. As of September 29, 2026, 8 recruiting or soon-opening trials on ClinicalTrials.gov name GAA as a gene.
What the GAA gene does
GAA makes acid alpha-glucosidase, also called acid maltase, an enzyme that works inside lysosomes, the cell's recycling centers. It breaks down glycogen, a stored form of sugar, into glucose.
Summarized from the GAA page on MedlinePlus Genetics, U.S. National Library of Medicine, checked September 29, 2026.
Conditions linked to GAA on Trial Friend
These condition pages list GAA among the genes behind the condition, checked against genetics references when each page was written.
The condition usually appears only when both copies of the gene carry a disease-causing variant. One variant alone usually means a person is a carrier.
All forms, infantile and late-onset, are caused by biallelic GAA variants; enzyme assay plus GAA sequencing confirms.
The condition usually appears only when both copies of the gene carry a disease-causing variant. One variant alone usually means a person is a carrier.
Same disorder as Pompe disease; all forms are biallelic GAA variants.
GAA mutation clinical trials
These recruiting or soon-opening trials mention GAA as a gene in their title, summary, eligibility rules or keywords. Some want people with a variant in it, and others study it more broadly, which is why each trial's own words are shown. In cancer trials the gene change is usually one found in the tumor rather than one a person inherited.
8 trials, checked September 29, 2026. The list refreshes from ClinicalTrials.gov every few hours.
All conditions linked to GAA gene mutations
Orphanet records how each gene relates to each condition. Orphanet links GAA to 2 rare conditions and lists variants in the gene as a cause of all of them.
- Causes it. Disease-causing variants in this gene are a direct cause of the condition.
GAA genetic test results and what a variant can mean
Labs sort each variant they find into 5 groups, from pathogenic and likely pathogenic through uncertain significance to likely benign and benign. Only the first 2 are usually treated as the cause of a condition. A variant of uncertain significance, or VUS, is one without enough evidence either way yet, and labs can reclassify it as research builds.
A genetic counselor or your doctor can explain what a specific result means for you and your family. Our genetic testing guide covers the terms, and MedlinePlus Genetics from the National Library of Medicine has a plain-language page on GAA.
GAA gene questions
What does the GAA gene do?
GAA makes acid alpha-glucosidase, also called acid maltase, an enzyme that works inside lysosomes, the cell's recycling centers. It breaks down glycogen, a stored form of sugar, into glucose. This summary follows MedlinePlus Genetics from the U.S. National Library of Medicine.
Are there clinical trials for people with GAA gene variants?
As of September 29, 2026, 8 recruiting or soon-opening trials on ClinicalTrials.gov name GAA as a gene. Each one is listed on this page with the words from the trial that mention the gene. ClinicalTrials.gov also lists 29 open trials for Pompe Disease and 31 for Glycogen Storage Disease Type II, and Match Me on Trial Friend can check those against age, sex, location and treatment history.
What conditions are linked to the GAA gene?
Orphanet links GAA to 2 rare conditions and lists variants in the gene as a cause of all of them. They include Glycogen storage disease due to acid maltase deficiency, infantile onset and Glycogen storage disease due to acid maltase deficiency, late-onset. Orphanet is the European rare disease database run by INSERM in Paris.
How is Pompe Disease inherited?
The inheritance pattern is autosomal recessive. The condition usually appears only when both copies of the gene carry a disease-causing variant. One variant alone usually means a person is a carrier. All forms, infantile and late-onset, are caused by biallelic GAA variants; enzyme assay plus GAA sequencing confirms.
How is Glycogen Storage Disease Type II inherited?
The inheritance pattern is autosomal recessive. The condition usually appears only when both copies of the gene carry a disease-causing variant. One variant alone usually means a person is a carrier. Same disorder as Pompe disease; all forms are biallelic GAA variants.
What does a GAA variant of uncertain significance mean?
A variant of uncertain significance, or VUS, is a change in the gene that labs don't yet have enough evidence to call disease-causing or harmless. It is not used on its own to diagnose a condition, and labs can reclassify it as research builds. A genetic counselor can explain what a specific result means for you and your family.
Sources
- Gene and condition links from Orphadata (Orphanet, INSERM US14), used under CC BY 4.0, read September 29, 2026.
- Trials from ClinicalTrials.gov, read September 29, 2026.
- GAA gene, MedlinePlus Genetics, U.S. National Library of Medicine.
- Inheritance and gene notes from the Trial Friend condition pages above, each checked against genetics references.
Other gene pages
The gene search covers every gene Orphanet links to a rare disease.