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Pompe disease
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Pompe disease

Pompe disease is an inherited disorder characterized by the buildup of glycogen in cells, which impairs muscle function and leads to progressive weakness and respiratory issues.

Overview

Pompe disease is an inherited disorder caused by the buildup of a complex sugar called glycogen in the body's cells. The accumulation of glycogen in certain organs and tissues, especially muscles, impairs their ability to function normally.

Researchers have described three types of Pompe disease, which differ in severity and the age at which they appear. These types are known as classic infantile-onset, non-classic infantile-onset, and late-onset.

Types of Pompe Disease

Classic Infantile-Onset Pompe Disease

The classic form of classic infantile-onset Pompe disease begins within a few months of birth. Infants with this disorder typically experience muscle weakness (myopathy), poor muscle tone (hypotonia), an enlarged liver (hepatomegaly), and heart defects. Affected infants may also fail to gain weight and grow at the expected rate (failure to thrive) and have breathing problems. If untreated, this form of Pompe disease leads to death from heart failure in the first year of life.

Non-Classic Infantile-Onset Pompe Disease

The non-classic infantile-onset form of Pompe disease usually appears by age 1. It is characterized by delayed motor skills (such as rolling over and sitting) and progressive muscle weakness. The heart may be abnormally large (cardiomegaly), but affected individuals usually do not experience heart failure. The muscle weakness in this disorder leads to serious breathing problems, and most children with non-classic infantile-onset Pompe disease live only into early childhood.

Late-Onset Pompe Disease

The late-onset type of Pompe disease may not become apparent until later in childhood, adolescence, or adulthood. Late-onset Pompe disease is usually milder than the infantile-onset forms of this disorder and is less likely to involve the heart. Most individuals with late-onset Pompe disease experience progressive muscle weakness, especially in the legs and the trunk, including the muscles that control breathing. As the disorder progresses, breathing problems can lead to respiratory failure.

Frequency

Pompe disease affects about 1 in 40,000 people in the United States. The incidence of this disorder varies among different ethnic groups.

Causes

Mutations in the GAA gene cause Pompe disease. 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. The enzyme normally breaks down glycogen into a simpler sugar called glucose, which is the main energy source for most cells.

Mutations in the GAA gene prevent acid alpha-glucosidase from breaking down glycogen effectively, which allows this sugar to build up to toxic levels in lysosomes. This buildup damages organs and tissues throughout the body, particularly the muscles, leading to the progressive signs and symptoms of Pompe disease.

Associated Gene

  • GAA

Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Other Names for This Condition

  • Acid maltase deficiency
  • Acid maltase deficiency disease
  • Alpha-1,4-glucosidase deficiency
  • AMD
  • Deficiency of alpha-glucosidase
  • GAA deficiency
  • Glycogen storage disease type II
  • Glycogenosis type II
  • GSD II
  • GSD2
  • Pompe's disease

Frequently Asked Questions

Both groups benefit from enzyme replacement therapy (ERT) with alglucosidase alfa, but dosing and timing differ. Classic infantile‑onset patients receive a higher dose (20 mg/kg weekly) started as early as possible to prevent cardiomyopathy and severe motor delay. Late‑onset patients typically receive 20 mg/kg every two weeks, with dosing adjusted based on functional assessments and antibody titers. In addition, late‑onset individuals may be managed with respiratory support and exercise programs, whereas infantile patients often require cardiac monitoring and more intensive physiotherapy.
Pulmonary function tests (spirometry, nocturnal oximetry) should be performed at diagnosis and then every 6–12 months. Early signs of respiratory compromise—declining forced vital capacity, nocturnal hypoventilation, or frequent respiratory infections—warrant initiation of non‑invasive ventilation (BiPAP) during sleep. As weakness advances, daytime BiPAP or cough‑assist devices may be added. In end‑stage disease, invasive ventilation (tracheostomy) is considered on a case‑by‑case basis.
Most U.S. states include Pompe disease in their tandem‑mass‑spectrometry newborn screen, which measures the activity of acid α‑glucosidase (GAA) in dried blood spots. A low enzyme activity triggers a reflex second‑tier test (often a repeat assay or DNA analysis). A positive screen does not confirm disease; it indicates the need for confirmatory enzyme testing in leukocytes or fibroblasts and molecular sequencing of the GAA gene to differentiate infantile‑onset from later‑onset forms.
Carriers are typically asymptomatic because one functional GAA allele provides sufficient enzyme activity. However, rare cases of mild, subclinical muscle enzyme elevations have been reported. Genetic counseling is recommended for siblings and extended family members, especially if they are planning pregnancy. Targeted carrier testing for the known familial GAA variants can clarify reproductive risk and guide prenatal or pre‑implantation testing if desired.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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