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Learning About Pompe

Know what to expect with Pompe disease

Pompe disease is a rare genetic disorder that can be inherited from both parents. It affects people all around the world, no matter what age or gender. For many years, scientists and clinicians believed that 1 in 40,000 people were living with Pompe disease. However, as diagnoses increase and newborn screening becomes more common, this estimate is likely to change.

Almost 20 years ago, there were few treatment options for people who developed Pompe disease symptoms. Today, there’s a much greater understanding of how Pompe disease can affect people over time and how it can be managed.

When we share knowledge that helps empower decision making—we Pompe Together.

Pompe disease is caused by an enzyme deficiency

In Pompe disease, the body is missing or has low levels of an enzyme called “acid alpha-glucosidase” (or GAA). GAA works in tiny cellular compartments called “lysosomes” to break down a complex sugar called “glycogen” into a simple sugar called “glucose.” The body uses glucose for energy.

Too much glycogen can damage tissue structure and function

Pompe disease is a multisystem disorder that has varying rates of progression, age of onset, organ involvement, symptoms, and overall severity.

When GAA isn’t working properly, glycogen can build up in tissues throughout the body, such as in smooth and skeletal muscles, the central nervous system, or the heart.

Glycogen is a thick, sticky substance that can cause loss of muscle function as it accumulates.

Skeletal muscles are often affected by Pompe disease. Excess glycogen in muscle cells can lead to weakness that worsens over time.

Pompe disease is the most common name for this disorder. But it’s also known by other names: 
  • Acid maltase deficiency, acid maltase deficiency disease, or AMD
  • Alpha-1,4-glucosidase deficiency, deficiency of alpha-glucosidase
  • GAA deficiency
  • Glycogen storage disease type II, GSD II, or GSD2
  • Pompe’s disease

Symptoms, age of onset, and disease severity can vary

Pompe disease can be different from one person to the next, depending on the type of GAA gene someone inherits. This gene can influence the amount of functioning GAA a person has in their body—as well as when their symptoms are noticeable and how quickly those symptoms progress.

Early onset of symptoms is often called infantile-onset Pompe disease (IOPD)

Pompe disease can be detected at birth in states where newborn screenings test for the disease. It can also be diagnosed when babies younger than 12 months develop symptoms; this type of Pompe disease is called IOPD.


In IOPD, babies may have less than 1% of functioning GAA in cells, resulting in symptoms that may appear within one to three months of life and become serious quickly. These babies need treatment right away in order to survive.

 

Symptoms may vary but can include:

  • Enlarged heart and difficulty breathing
  • Feeding problems, poor weight gain, and failure to thrive
  • Droopy body that’s similar to a rag doll
When symptoms develop after one year, it’s often called late-onset Pompe disease (LOPD)

LOPD, or delayed-onset Pompe disease, refers to people who are diagnosed at any age from early childhood throughout adulthood. In LOPD, someone may have anywhere from about 1% to 30% of functioning GAA in their cells.

Lower levels of functioning GAA can cause symptoms that appear earlier in life and progress faster than in people with higher levels of GAA.

Multiple parts of the body may be affected

The most common symptoms of Pompe disease are weakness in muscles that control movement and breathing problems that become more difficult over time. Other parts of the body can be affected, too.

Brain: Having too much glycogen in the nervous system can make it hard to remember things, learn new information, focus, or make decisions.

Vascular system: Most people with LOPD don’t usually have heart problems. However, some may experience issues like bleeding, blood clots, or problems with their blood vessels.

Respiratory system: When the muscles around the ribs and in the diaphragm get weak, it can make it hard to breathe and sleep. Some people might need help from a ventilator machine to breathe properly. Severe breathing problems can become life-threatening.

Gastrointestinal system: Pompe disease can affect parts of the digestive system, like the esophagus, stomach, and intestines. This might cause problems like not gaining enough weight, stomach aches, nausea, or vomiting.

Skeletal muscles: Many people with Pompe disease have weak and shrinking muscles throughout their body. This makes it hard for them to walk, go up stairs, or stand up from a chair or the floor. They might also fall often, feel very tired, or have pain all the time.

Testing is available, but getting diagnosed can take time

The earlier someone is diagnosed with Pompe disease, the sooner they can get the right treatment. Newborns with IOPD are often diagnosed within the first few months of life based on signs, symptoms, and the results of laboratory testing. In older children and adults, diagnosis can take much longer. 

Delays in diagnosis are common

Some states and countries offer screening for Pompe disease at birth. In other cases, getting a correct diagnosis can take years—and many doctor visits—for children and adults with LOPD. There are two big reasons for this delay:

 

1. The disease is very rare and it’s not top of mind for some doctors.

 

2. Some of the symptoms of Pompe disease are signs of other, more common conditions. In fact, up to about 50% of people with Pompe disease are incorrectly diagnosed with something else first.

 

Going to a treatment center that specializes in rare diseases may help someone with puzzling symptoms get a diagnosis sooner.

 

Here’s a list of places to start.

 

Delays in diagnosis are common
Multiple tests can be used 

Once a doctor thinks someone might have Pompe disease, the tests to diagnose it are fairly straightforward. 

A skin or muscle biopsy is when a small tissue sample is taken to measure levels or activity of the GAA enzyme in muscle cells. If the results are low, it could mean Pompe disease. 

Blood and urine tests can show signs of glucose buildup and muscle damage related to Pompe disease.


Genetic testing (also used in newborn screening in some states and countries) can be used to diagnose Pompe disease. It may even be helpful in family planning if another relative has already been diagnosed.

A chest x-ray and electrocardiogram (ECG) may be used to look for signs of heart disease in possible cases of infantile-onset Pompe disease.

 

Understand what a genetic counselor can do.

It takes a team

Because of the many challenges that go along with Pompe disease, it often helps to have a team of doctors, therapists, and counselors to support patients and their caregivers.


Find out who’s on the healthcare team.

Current treatment methods help replace the missing enzyme in the body

Today, the main treatment for Pompe disease is enzyme replacement therapy (ERT). By replacing the missing GAA enzyme, ERT can help to stop the buildup of glycogen and slow down progressive muscle weakness. ERT is given to patients through an intravenous (into the vein) infusion every other week.


ERT has helped children with infantile-onset Pompe disease live longer. Most people with the late-onset form experience slowed progression while using ERT, although the benefits of treatment may go away over time.


One challenge with ERT is that it can’t always reach all the places in the body that need help. Another issue is that some people develop an immune system reaction that fights the treatment and makes it less effective.


Even with ERT, some people may continue to have symptoms and may experience disease progression over time.

Current treatment methods
Supportive care 

For people with Pompe disease, there are extra treatments that can help. These treatments are designed to meet each person’s specific needs.

Therapists can help with trouble breathing, weak muscles, eating the right food, and difficulty speaking. They can also provide tools like canes or walkers to make moving around easier.

Counselors can offer educational and emotional support. Genetic counselors can provide information about Pompe disease, while other counselors talk to both patients and caregivers to help them cope with some of the big life changes that can come with Pompe disease.

Find out where to turn for emotional support.

Researchers are studying the potential of gene therapy
Researchers are studying the potential of gene therapy
Looking Ahead

Researchers are studying the potential of gene therapy

Scientists are working towards developing new treatment options to correct the defective (mutated) GAA gene, which causes Pompe disease. This area of research is known as gene therapy and there are already special investigational studies underway called clinical trials.

Although these gene therapy treatments are not approved yet, if successful, they could help muscles work the way they’re supposed to in people with Pompe disease.