What is Pompe Disease?

Pompe disease is a Lysosomal disorder caused by the accumulation of a complex sugar called glycogen in muscles and other organs and tissues. The lack of acid alpha-glucosidase, the enzyme responsible for breaking glycogen into smaller molecules, results in progressive damage in cardiac, skeletal, respiratory, and smooth muscles.
Individuals with Pompe disease may lose the ability to move independently, which may also limit their breathing capacity. Infants with PD have severe cardiac involvement.

How to diagnose?
Enzymatic testing in dried blood spots demonstrating a low level of alpha-glucosidase activity and GAA gene sequencing.
The diagnosis of LOPD can be challenging and may take many years, often involving muscle biopsies.

What is the treatment?
Enzyme replacement therapy is the standard treatment. In infants with IOPD, ERT produces heart size, improves heart function, and prolongs survival. Infants will need to undergo immunosuppressive protocols before starting ERT. Supportive therapies such as respiratory support and nutritional management are essential to care for infants with IOPD.

For individuals with LOPD, there are several FDA-approved ERT products available, including an ERT administered together with an oral medication. Other treatment options are in the pipeline and clinical development, including gene therapy and small molecule therapies. Appropriate care and adjunct therapies will lead to the alleviation of symptoms and improved quality of life.

Main Types

Classic Infantile Onset

Infantile Onset Pompe disease (IOPD) usually appears in infants within a few months of birth, and one of the early symptoms is the difficulty of gaining weight and the ability to grow at a regular rate. Early diagnosis and intervention are crucial for optimizing survival outcomes. If left untreated, IOPD is fatal within the first year of life.

Symptoms include muscle weakness, poor muscle tone, enlarged liver, enlarged tongue, trouble breathing, frequent lung infections,  and hearing problems. Rapidly progressive cardiomyopathy leads to heart failure and respiratory distress. 

Non-classic Infantile-onset

Non-classic infantile Pompe disease, also known as late-onset Pompe disease, is a less aggressive variant compared to the classic form of infantile Pompe disease. While it still presents within the first year of life, the symptoms tend to develop more slowly, and the progression of the disease is less rapid. Children with non-classic IOPD may survive into early childhood and beyond with variable degrees of cardiac and muscular symptoms.

Symptoms include muscle weakness, delayed motor skills, and hypertrophic cardiomyopathy.


Late-onset Pompe disease (LOPD) refers to a spectrum of Pompe disease that manifests later in life, typically beyond the first year of childhood. Individuals with LOPD may experience symptoms in early or late childhood, adolescence, or adult years. Unlike IOPD, the heart is less likely to be involved. The progression of LOPD is more gradual, however, the life expectancy and quality of life are significantly impacted without treatment and management of those symptoms.

Symptoms can vary widely and may include progressive muscle weakness (such as those closer to the trunk), mobility limitation, breathing problems, shortness of breath, morning headaches, scoliosis and/or curved spine, falling often, weight loss, difficulty hearing, and swallowing.

Prevalence in the US is 1 in 40,000


Poor feeding (IOPD)

Low muscle tone (IOPD) | (LOPD)

Frequent respiratory infections (IOPD)

Enlarged heart (IOPD)

Breathing issues (IOPD) | (LOPD)

Muscle weakness (IOPD) | (LOPD)

Abnormal gait (LOPD)


Enzyme Replacement Therapy (ERT)

ERT with oral pharmacological chaperone

*Other treatments under development