Diagnosis guide for clinicians
Pompe disease: when to suspect it and what to test
Pompe disease is an autosomal recessive glycogen storage disease in which deficient acid alpha-glucosidase (GAA) lets glycogen build up in many tissues, especially skeletal muscle and the heart.Acta Myologica diagnostic algorithm
Late-onset Pompe disease (LOPD) can begin from the first to the seventh decade with progressive proximal weakness, mostly in the legs, and respiratory insufficiency that may be worse than the limb weakness would suggest.GeneReviews
A 2023 Turkish neurology consensus, organized and funded by Sanofi, reports diagnostic delays of 5 to 30 years from symptom onset, and says almost one-third of patients receive an incorrect diagnosis before they see a metabolic or neuromuscular expert.Turkish neurology consensus
Red flags for Pompe disease
What the cited sources describe, grouped by life stage and organ. Each line links to its source.
Muscles (late-onset disease)
- Progressive proximal weakness, found in about 95% of people with untreated late-onset disease, mostly in the lower limbs.GeneReviews
- Trouble climbing stairs or rising from a chair, excessive fatigue, back pain, exercise intolerance and muscle aches.Acta Myologica diagnostic algorithm
- Axial and proximal weakness in a limb-girdle pattern that mainly affects the pelvic girdle.Acta Myologica diagnostic algorithm
- Scapular winging, muscle aches and hyperCKemia, which the 2023 consensus lists among the skeletal muscle signs.Turkish neurology consensus
- Adults often recall childhood trouble keeping up in sports; fatigue and difficulty rising, climbing stairs and walking later prompt a visit.GeneReviews
- A Gowers sign, reduced deep tendon reflexes and joint contractures.GeneReviews
Breathing
- Respiratory insufficiency without obvious heart involvement that may be more severe than expected for the level of skeletal muscle weakness.GeneReviews
- Restrictive respiratory insufficiency from diaphragm weakness can be the first sign, even while the patient still walks, and breathlessness may be worse lying flat.Turkish neurology consensus
- Morning headache, daytime sleepiness, obstructive sleep apnea and recurrent pneumonia.Acta Myologica diagnostic algorithm
- Exertional dyspnea, orthopnea and more frequent respiratory infections.GeneReviews
Laboratory findings
- Raised CK, LDH, AST and ALT in most patients on first-line labs.Acta Myologica diagnostic algorithm
- HyperCKemia, which the 2013 algorithm calls usually mild at 2 to 5 times normal and which can be the only finding in a patient without symptoms.Acta Myologica diagnostic algorithm
- Other sources report higher CK, up to 15-fold in the 2023 consensus and as high as 2000 IU/L in GeneReviews, so a markedly raised CK does not argue against Pompe disease.Turkish neurology consensus
- The 2013 algorithm names 3 presentations that should raise suspicion, namely proximal or axial weakness with or without breathing symptoms, restrictive respiratory insufficiency and asymptomatic hyperCKemia.Acta Myologica diagnostic algorithm
Other organs (late-onset disease)
- Scoliosis, lumbar hyperlordosis and rigid spine.Acta Myologica diagnostic algorithm
- Facial weakness, eyelid ptosis, tongue weakness and trouble swallowing.Turkish neurology consensus
- Sensorineural hearing loss and a low body mass index.Acta Myologica diagnostic algorithm
- Some adults develop arterial disease, including dilatation of the ascending thoracic aorta and ectasia of the basilar and internal carotid arteries, which can cause transient ischemic attacks or third nerve palsy.GeneReviews
- Intracranial aneurysms and vertebrobasilar dolichoectasia.Turkish neurology consensus
Infants (infantile-onset disease)
- An out-of-range newborn screen; Pompe disease is on the US Recommended Uniform Screening Panel, and a single abnormal result is not enough for a diagnosis.GeneReviews
- GeneReviews defines infantile-onset disease as onset before 12 months with cardiomyopathy; an infant with weakness but no cardiomyopathy is classed as late-onset.GeneReviews
- Poor feeding and growth, motor delay or weakness, and respiratory infections or difficulty.GeneReviews
- Hypotonia or weakness in 52% to 96% and an enlarged tongue in 29% to 62% of infants at presentation, per GeneReviews.GeneReviews
- Cardiomegaly or hypertrophic cardiomyopathy, with a shortened PR interval and a broad QRS complex on ECG.GeneReviews
- Before newborn screening, infantile-onset disease was more often recognized clinically at a median age of 4 months.GeneReviews
Family history
- Affected siblings or parents who are related to each other; absence of a known family history does not rule out the diagnosis.GeneReviews
Often mistaken for
Diagnoses patients commonly carry first, and why the sources say they are confused.
| First diagnosis | Why it is confused |
|---|---|
| Limb-girdle muscular dystrophy | Progressive weakness of the legs, pelvis and shoulders. GeneReviews notes that early respiratory muscle involvement helps set late-onset Pompe disease apart.GeneReviews |
| Polymyositis or another inflammatory myopathy | Unexplained, progressive, symmetric muscle weakness.GeneReviews |
| Becker or Duchenne muscular dystrophy | Progressive proximal weakness, respiratory insufficiency and trouble walking.GeneReviews |
| Myasthenia gravis | Proximal weakness, and in some patients ptosis or bulbar weakness.Turkish neurology consensus |
| Spinal muscular atrophy | Progressive proximal weakness and atrophy with mildly raised CK.Turkish neurology consensus |
| McArdle disease or another glycogen storage disease | Raised CK and muscle cramping with exertion, as in McArdle disease.GeneReviews |
| Unclear muscular dystrophy, hypotonia or weakness | Named in the 2023 consensus as one of the most common earlier diagnoses.Turkish neurology consensus |
| Ankylosing spondylitis or degenerative back disease | Named in the same consensus as a common earlier diagnosis; back pain and a rigid spine are described in late-onset disease.Turkish neurology consensus |
| Infant hypertrophic cardiomyopathy, SMA type 1, Danon disease or myocarditis | These are GeneReviews' differentials for infantile-onset disease. SMA type 1 lacks cardiomegaly, and myocarditis lacks hypotonia and weakness.GeneReviews |
Codes patients often carry before this diagnosis
For spotting the pattern in a problem list or registry. Descriptions are checked daily against NLM's ICD-10-CM service; this is not coding advice.
G71.031, G71.032, G71.033, G71.0340, G71.035, G71.036, G71.038, G71.039Late-onset Pompe disease often mimics limb-girdle muscular dystrophy.Turkish neurology consensus
M33.20, M33.21, M33.22Polymyositis is on the GeneReviews differential for late-onset Pompe disease.GeneReviews
G72.9An unexplained myopathy with proximal or axial weakness is a presentation the 2013 algorithm says should raise suspicion.Acta Myologica diagnostic algorithm
R74.8Isolated hyperCKemia can be the only finding in a patient without symptoms.Acta Myologica diagnostic algorithm
R74.01AST and ALT are raised in most patients on first-line labs.Acta Myologica diagnostic algorithm
G47.33Sleep apnea is among the respiratory symptoms that can come first.Acta Myologica diagnostic algorithm
J96.10, J96.11, J96.12Respiratory insufficiency can exceed the limb weakness and is the main cause of illness and death.GeneReviews
What to test, step by step
The testing order the cited guidance describes, by who it applies to. It summarizes published guidance and is not a plan for any one patient.
Anyone with unexplained proximal or axial weakness, restrictive respiratory insufficiency or hyperCKemia
- History, examination and first-line labs
A 2013 diagnostic algorithm starts with clinical history, neurological examination and routine labs, including CK, LDH, AST and ALT.Acta Myologica diagnostic algorithm
Suspected late-onset disease
- Electromyography
EMG can show myopathy, though some muscles look normal. In adults, needle EMG of the paraspinal muscles may be needed to show abnormalities. Nerve conduction is typically normal, particularly at diagnosis.GeneReviews
- Look for electrical myotonia
Both algorithms place EMG and nerve conduction studies before the dried blood spot. The 2023 consensus calls electrical myotonia without clinical myotonia, particularly in paraspinal muscles, highly suggestive.Turkish neurology consensus
- Dried blood spot GAA activity
The 2013 algorithm calls the dried blood spot assay a crucial step. Citing the Pompe Disease Diagnostic Study Group, it advises repeating a positive result and says a negative result should point toward other neuromuscular disorders.Acta Myologica diagnostic algorithm
Anyone with a positive dried blood spot
- Confirm with a second test
Confirm with GAA activity in leukocytes, fibroblasts or muscle, or with GAA gene analysis.Turkish neurology consensus
Biochemical confirmation
- GAA activity in lymphocytes or leukocytes
GeneReviews says deficient GAA activity in isolated lymphocytes or mixed leukocytes establishes the diagnosis. Partial deficiency, 2% to 40% of normal, is associated with late-onset disease.GeneReviews
Fibroblast, muscle or purified lymphocyte assays
- Reading a tissue GAA result
The 2013 algorithm treats activity over 40% of control as normal and under 30% as deficient. It calls 30% to 40% borderline, possibly a carrier or a patient, and advises GAA gene analysis; GeneReviews instead places 2% to 40% in the late-onset range.Acta Myologica diagnostic algorithm
Molecular confirmation
- GAA gene sequencing
Finding pathogenic or likely pathogenic variants in both GAA copies establishes the diagnosis. GeneReviews calls GAA testing increasingly the preferred confirmatory test.GeneReviews
Anyone with one or no variant found by sequencing
- Deletion/duplication analysis
GeneReviews lists gene-targeted deletion/duplication analysis as the next step. Sequencing finds about 95% to 96% of pathogenic variants, and deletion/duplication analysis about 4%.GeneReviews
Weakness with a broad differential
- Multigene panel or exome
GeneReviews lists a multigene panel that includes GAA and other genes of interest, or exome or genome sequencing when the differential is most efficiently covered by broad genomic testing.GeneReviews
Supporting test
- Urinary glucotetrasaccharide (Hex4)
Hex4 is highly sensitive in infantile-onset disease but less sensitive in late-onset disease, and is also raised in other glycogen storage diseases.GeneReviews
Infants
- After an out-of-range newborn screen
Follow-up usually includes GAA gene testing. While confirmation is pending, the evaluation may include examination, echocardiography, CK and urinary Hex4.GeneReviews
Anyone starting enzyme replacement therapy, especially infants
- CRIM status before enzyme therapy
GeneReviews calls it appropriate to find cross-reactive immunologic material (CRIM) status before starting enzyme replacement therapy. CRIM-negative patients generally develop high-titer antibodies and need immunomodulation early.GeneReviews
Adults with late-onset disease
- Label criteria for Pombiliti with Opfolda
The labels indicate the combination for adults with late-onset Pompe disease who weigh at least 40kg and are not improving on their current enzyme replacement therapy.Pombiliti and Opfolda labels
Where testing goes wrong
- A normal CK does not rule out late-onset disease; GeneReviews says CK may be normal in some patients.GeneReviews
- A normal EMG or muscle biopsy does not rule it out either, according to the 2023 neurology consensus.Turkish neurology consensus
- The most frequent muscle biopsy finding is a vacuolar myopathy with vacuoles that may stain PAS-positive, but a biopsy can be normal or show only nonspecific changes.Acta Myologica diagnostic algorithm
- Pseudodeficiency alleles c.1726G>A and c.2065G>A, relatively common in people of Asian ancestry, interfere with interpreting GAA enzyme results, as newborn screening programs in Missouri and New York found. GeneReviews urges caution matching gene and enzyme results when there are no clinical features.GeneReviews
- Dried blood spot results depend on correct spotting, since too much or too little blood on the card can skew them.Acta Myologica diagnostic algorithm
- Purified lymphocyte assays can give false-negative results if neutrophils contaminate the sample.Acta Myologica diagnostic algorithm
- Fibroblast GAA testing is reliable but slow, since the cell culture takes about 4 to 6 weeks.Acta Myologica diagnostic algorithm
- One pathogenic variant plus a variant of uncertain significance, or 2 such variants, neither establishes nor rules out the diagnosis.GeneReviews
- The consensus calls the slowly developing respiratory form a likely cause of late diagnosis, because patients may tolerate breathing problems for years.Turkish neurology consensus
Where to test
- NIH Genetic Testing Registry: Pompe disease: Lists clinical GAA enzyme assays, GAA sequencing, deletion/duplication tests and neuromuscular panels submitted by laboratories. NIH does not independently verify submissions or endorse any laboratory.NIH GTR
- NIH's Genetic Testing Registry listed 156 tests for a search of “Pompe disease” on November 9, 2026. NIH does not endorse or verify the labs it lists.
Family screening and referral
Who else in the family
- When both parents carry a GAA pathogenic variant, each sibling has a 25% chance of being affected, a 50% chance of being a carrier without symptoms and a 25% chance of being neither.GeneReviews
- GeneReviews says testing all at-risk siblings of any age is warranted for early diagnosis and treatment.GeneReviews
- For an at-risk newborn sibling not tested before birth, the family GAA variants or GAA activity can be tested alongside newborn screening.GeneReviews
- Carrier testing for relatives and prenatal or preimplantation genetic testing are possible once the family variants are known.GeneReviews
Who to refer to
- A 2023 neurology consensus describes Pompe disease as needing a multidisciplinary team for its pulmonary, neuromuscular, orthopedic and gastrointestinal features.Turkish neurology consensus
- The same consensus says early referral of patients with unspecific symptoms to expert centers is considered an improved strategy for earlier diagnosis.Turkish neurology consensus
- GeneReviews advises that medical therapy for heart conduction problems be handled by a cardiologist familiar with Pompe disease.GeneReviews
- GeneReviews recommends starting enzyme therapy in centers equipped to give emergency care, because of infusion reactions including rare anaphylaxis and, in infants, existing heart and breathing compromise.GeneReviews
Find a specialist by state
From the CMS NPI Registry, a public directory of US clinicians by registered specialty. A listing is not an endorsement and says nothing about experience with Pompe disease; patient organizations and academic centers can often name experienced clinicians.
ICD-10-CM codes for Pompe disease
For orders, referrals and prior authorization. Each code is checked daily against NLM's ICD-10-CM service.
Once the diagnosis is confirmed
For the patient: why your doctor ordered this test
Plain language a patient can read or take home.
Your doctor ordered this test because some of your symptoms can be a sign of Pompe disease. It is a rare muscle illness that runs in families.
With Pompe disease, the body is missing enough of an enzyme called GAA. A type of sugar called glycogen then builds up in the muscles.
The first test is often a few drops of blood on a card. If the result is low, a second test checks the enzyme again or looks at the GAA gene.
Pompe disease can weaken the breathing muscles. Your doctor may test your breathing while you sit and while you lie down.
If you have Pompe disease, your brothers and sisters may need testing too, even if they feel fine.
Questions clinicians ask about Pompe disease testing
What is the first test for suspected late-onset Pompe disease?
A dried blood spot GAA enzyme assay is the screening test in published algorithms, after history, examination, routine labs including CK, and EMG with nerve conduction studies. The 2013 algorithm in Acta Myologica repeats a positive spot before confirmation, as does a 2023 Sanofi-supported Turkish neurology consensus in its own order. A positive result is confirmed by GAA activity in leukocytes, lymphocytes, fibroblasts or muscle, or by GAA gene analysis. GeneReviews (updated August 21, 2025) calls GAA molecular testing increasingly the preferred confirmatory test.
Does a normal CK rule out late-onset Pompe disease?
No; GeneReviews says CK is raised in all infantile-onset patients but may be normal in some late-onset patients. The 2023 neurology consensus adds that normal EMG or muscle biopsy findings do not exclude the diagnosis either.
How are GAA variants of uncertain significance handled?
Per GeneReviews, one pathogenic variant plus a variant of uncertain significance, or 2 such variants, neither establishes nor rules out Pompe disease. When sequencing finds only one or no variant, GeneReviews lists gene-targeted deletion/duplication analysis as the next step. The 2013 algorithm says a single variant is inconclusive and leads back to biochemical GAA testing in another tissue.
Why can GAA enzyme results be misleading?
Pseudodeficiency alleles such as c.1726G>A and c.2065G>A, relatively common in people of Asian ancestry, interfere with interpreting GAA enzyme results in newborn screening, according to GeneReviews, which urges caution when there are no clinical features. Lymphocyte assays can read falsely normal if neutrophils contaminate the sample, per the 2013 algorithm.
Which treatments are FDA-approved for late-onset Pompe disease?
The Lumizyme label covers Pompe disease, and the Nexviazyme label covers late-onset disease in patients 1 year of age and older. Pombiliti with Opfolda is labeled for adults with late-onset disease who weigh at least 40kg and are not improving on their current enzyme replacement therapy.
What is the ICD-10 code for Pompe disease?
The ICD-10-CM code is E74.02, Pompe disease, per the National Library of Medicine's ICD-10-CM lookup checked November 8, 2026.
Sources
- Pompe Disease. GeneReviews, University of Washington, Seattle, via NCBI Bookshelf (NBK1261); Sperry E, Leslie N, Berry L, Pena L, 2025-08-21.
- Expert opinion on the diagnostic odyssey and management of late-onset Pompe disease: a neurologist's perspective. Frontiers in Neurology, Perspective (Erdem Ozdamar S et al; Sanofi Turkey organized the meetings, invited and paid the experts for their time and funded editorial support), via PubMed Central, 2023-05-17.
- Early is better? A new algorithm for early diagnosis in Late Onset Pompe Disease (LOPD). Acta Myologica, editorial (Toscano A, Montagnese F, Musumeci O), via PubMed Central, 2013-10.
- POMBILITI (cipaglucosidase alfa-atga) prescribing information (Opfolda label, setid d7c38298-37db-5a80-e053-2995a90aee40, effective November 27, 2024, carries the same indication). Amicus Therapeutics US, via DailyMed, 2026-08-12.
- NEXVIAZYME (avalglucosidase alfa-ngpt) prescribing information. Genzyme Corporation, via DailyMed, 2025-06-05.
- LUMIZYME (alglucosidase alfa) prescribing information. Genzyme Corporation, via DailyMed, 2025-01-10.
- Glycogen storage disease, type II - NIH Genetic Testing Registry (GTR) - NCBI. National Center for Biotechnology Information, NIH, 2026-11-08.
- ICD-10-CM search results for "pompe" (Clinical Table Search Service). National Library of Medicine, 2026-11-08.
A reference for licensed professionals, checked against its sources on November 8, 2026. It summarizes what the cited guidance says and does not tell anyone how to diagnose or treat a specific patient. Guidelines change; the current guideline and the treating clinician's judgment govern. Trial Friend is an independent information service, not a medical provider.
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