A genetic disorder in which a complex sugar (glycogen) builds up in specific body cells called lysosomes is known as Pompe disease. It often occurs when a person has a lack of a digestive enzyme called GAA (acid alpha-glucosidase). People who develop a severe form of Pompe disease can experience severe muscle weakness or loss. One way to treat this condition and prevent serious complications is early detection.
Furthermore, this condition is a type of glycogen storage disease that results from a deficiency of GAA, which breaks down complex sugars in the body. Sometimes, this condition is called acid maltase deficiency or glycogen storage disease type II (GSD2).
Healthcare professionals usually refer to Pompe disease as a lysosomal storage disease. A part of the body cells that hold and recycle some substances is called the lysosomes. Without treatment, this condition can negatively affect multiple organs in the body, including the heart and skeletal muscles.
In general, this disorder occurs rarely and affects about 1 in every 40,000 people in the U.S.
Types of Pompe Disease
Healthcare providers have divided this condition into 2 types based on the age of onset and severity of the symptoms. For example:
Infantile-onset
This type occurs during infancy, and it is the most severe form of Pompe disease. Usually, it is caused by a lack of GAA, which breaks down the lysosomes. While the baby may not have any symptoms at birth, they usually begin within the first year of life (usually around 4 months of age). Commonly, they experience the following symptoms. Examples include enlarged liver and heart muscle due to cardiomyopathy. Usually, this type of Pompe disease progresses quickly, and without immediate treatment, it may lead to death.
Late-onset (juvenile or adult-onset)
In such cases, the symptoms often appear before 1 year of age, but without an enlarged heart muscle. Usually, in people with late-onset, the body still produces some GAA. That’s why this type of condition is milder and progresses, but at a slower pace. The most common symptoms include muscle weakness (also known as myopathy) and breathing problems. If the condition is left untreated, it may lead to serious respiratory complications.
Symptoms
The primary symptom of this condition is progressive muscle weakness (especially in the skeletal muscles of the hips, legs, shoulders, arms, and diaphragm). Infants can also have poor muscle tone (hypotonia), cardiomegaly (enlarged heart muscle), hepatomegaly (enlarged liver), and macroglossia (enlarged tongue). However, Pompe disease can also cause other symptoms depending on the type of the condition. Check below some examples:
Infantile-onset Symptoms
- Difficulty gaining weight
- Trouble breathing
- Feeding problems
- Respiratory infections
- Hearing issues
In people with late-onset, this condition often causes milder symptoms that progress more slowly. For example:
- Weakness in the legs
- Walking problems
- Muscle pain
- Frequent falls
- Loss of the ability to exercise
- Dyspnea (shortness of breath)
- Respiratory infections
- Headaches
- Tiredness
- Unusual weight loss
- Dysphagia (swallowing problems)
- Arrhythmia (irregular heart rhythm)
Do not hesitate to see a doctor if you or your baby experiences any of the previous symptoms. Early detection and proper treatment can help prevent life-threatening complications of Pompe disease.
Causes
This condition occurs due to a genetic mutation of the GAA gene. It is responsible for producing enzymes (acid alpha-glucosidase) that the body uses to break down glycogen (a complex form of sugar). In normal circumstances, the body converts glycogen into glucose that is used for energy. These enzymes work within specific body’s cells known as lysosomes. They also recycle centers within the cells and help break down into substances that the body uses as energy.
In people with this abnormal gene, the production of this enzyme is either reduced or even blocked. Without this enzyme, the body is not able to break down glycogen effectively, which often leads to the buildup of lysosomes in the body cells. As a result, it leads to severe muscle damage and other symptoms.
Usually, this condition is inherited in an autosomal recessive manner. It means you get the abnormal gene from each biological parent during pregnancy. While parents carry the abnormal gene that causes Pompe disease, they usually do not have any symptoms that resemble this genetic disorder.
Complications
People with Pompe disease can also experience some complications, especially if they do not get immediate treatment. Check below some of them:
- Severe and progressive heart muscle enlargement (cardiomegaly) that often causes heart failure
- Hypotonia
- Frequent lung infections caused by respiratory muscle weakness
- Gastrointestinal problems (such as feeding problems, poor weight gain, and others)
- Macroglossia (enlarged tongue)
- Sleep-disordered breathing, which significantly increases the risk of developing pneumonia
- In rare cases, stroke, intracranial aneurysms, and other vascular disorders
- Mental health issues (such as anxiety, depression, cognitive impairment, and others)
- Urinary or bowel incontinence
The previous list does not contain a complete list of Pompe disease complications. While in most cases this condition is fatal (especially for babies), with immediate treatment, you can prevent the previous complications.
In addition, this condition cannot be prevented because it is a genetic disorder, in which the abnormal genes are passed during pregnancy from biological parents to their children. The only way to prevent this disorder is to perform genetic tests to make sure you do not have this abnormal gene. It is very important to understand the risks of having children with Pompe disease.
Diagnosis
First, doctors will perform a physical examination to check for abnormalities linked to the disease. They can also ask some questions about the symptoms and family history to get more clues about the disease. However, to confirm or rule out Pompe disease, doctors often perform the following tests. These include:
- Electromyography (EMG) – This test is used to determine how well your muscles are working.
- Heart studies – These often include an electrocardiogram (EKG or ECG) to measure the electrical activity of the heart and an echocardiogram (echo).
- Sleep studies – These studies are often performed to record some body functions while you sleep.
- Pulmonary function test – This test is performed by doctors to check the lung capacity.
Treatment
The main treatment for people with Pompe disease is enzyme replacement therapy (ERT). It helps supply the deficiency of the GAA, which helps break down glycogen. Usually, this treatment is given to the patients intravenously (IV). It often contains one of the following medicines, including Alglucosidase alfa or Avalglucosidase alfa. Furthermore, these medicines also help to reduce heart size, keep normal heart function, improve muscle function (including tone and strength), reduce the progression of the disease, and can also reduce glycogen buildup in the body cells. In more severe cases, physicians can also recommend physical or occupational therapies, a feeding tube, or mechanical ventilation for people with breathing problems.
In addition, healthcare providers are studying clinical trials of Pompe disease gene therapy. During this procedure, experts are trying to replace damaged genes with healthy ones. As a result, it will help the body to produce acid alpha-glucosidase properly.
Frequently Asked Questions
What is the Pompe disease life expectancy?
This condition is usually fatal without immediate treatment. Death often occurs because of respiratory or heart failure. However, people with the late-onset type of Pompe disease can live longer because it progresses more slowly.
What are the symptoms of Pompe disease?
The symptoms are usually different among people because they depend on the type and severity of the condition. Check below some general symptoms:
- Severe muscle weakness and poor muscle tone (hypotonia)
- Enlarged heart muscle
- Extreme tiredness
- Mobility issues
- Frequent lung infections
- Enlarged tongue
Immediately contact your healthcare professional if any of the symptoms listed above occur.
Can Pompe disease be cured?
Unfortunately, there is no way to cure this disorder. That’s why the treatment goal is to reduce the progression of the disease, relieve the symptoms, and improve your quality of life. However, you can perform a genetic test before pregnancy to make sure you do not have this abnormal gene that causes Pompe disease. It is very important to understand the risks of having children with this genetic disease. Ask your healthcare provider if you have additional questions.
