Lysosomal Storage Disorders Support Society

What is Pompe Disease?

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.

 

What causes Pompe disease?

Pompe is caused by mutations in the GAA gene, which provides instructions for making an enzyme called acid alpha-glucosidase (also known as acid maltase). The deficiency of this enzyme hampers the break down of a complex sugar molecule called glycogen into a simple sugar molecule called glucose, which cells can use to produce energy.

The disease is also known as acid alpha-glucosidase deficiency, acid maltase deficiency, or glycogen storage disease type 2.

 

Types and Symptoms of Pompe

Researchers have described three types of Pompe, which differ in severity and the age at which they appear:

          • classic infantile-onset
          • non-classic infantile-onset
          • late-onset

The symptoms of classic form of infantile-onset Pompe appear 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 leads to death from heart failure in the first year of life.

The symptoms of non-classic infantile-onset Pompe usually appear by age 1. This type 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 live only into early childhood.

Video Credit: Osmosis

The symptoms of late-onset Pompe disease may not become apparent until later in childhood, adolescence, or adulthood. Muscle weakness, especially in the torso and legs, is well-known in this form of the disorder. Patients may develop a waddling or swaying gait, and find it difficult to stand, run, or climb stairs. Spinal muscular weakness may lead to scoliosis (a sideways curvature of the spine), especially in adolescents. Patients may also experience muscle cramps, headaches and fatigue. Respiratory problems, caused by weakness in the muscles used for breathing, may also develop.

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Pompe Disease

Late-onset Pompe 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 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.

 

How is Pompe disease diagnosed?

Diagnosis of Pompe disease can be done through enzyme assay using blood samples to check the levels of the enzyme associated with Pompe.

 

A minimally invasive way is to check for the enzyme’s presence through a skin biopsy. From the biopsy, cells called fibroblasts are the best source to test for enzyme activity.

 

Genetic testing can be done to identify the responsible mutation.

Pompe disease treatment in India

There is no cure for Pompe. Myozyme® (alglucosidase alfa), developed by Sanofi Genzyme, is an enzyme replacement therapy (ERT) that can help control the symptoms of Pompe, prevent irreversible damage and improve quality of life.

Treatment for Pompe disease is lifelong, needs to be imported, and extremely expensive, costing several lakhs to few crore rupees per year, depending on the patient’s body weight and dose required. In India, some patients are receiving treatment free of cost through humanitarian aid.

 

Clinical Trials for Pompe

To get information about ongoing/future clinical trials in India for Pompe, click here.

 

If you or someone you know from India has been diagnosed with Pompe, please register with us by filling out this form to get further information and support.

Frequently Asked Questions (FAQs)

Pompe 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.

Symptoms begin in the first months of life and include feeding problems, poor weight gain, muscle weakness, floppiness, and head lag. Respiratory difficulties are often complicated by lung infections. The heart is grossly enlarged. Many infants with Pompe also have enlarged tongues.

The classic form of infantile-onset Pompe 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.

The non-classic form of infantile-onset Pompe 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,

Most individuals with late-onset Pompe 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.

Pompe can be life-threatening if left untreated. Patients with classic infantile-onset type rarely live past 1 year of age. Patients with non-classic infantile–onset type may live to early childhood. Children with late-onset types of Pompe can live longer as the disease progresses more slowly.

Life expectancy in Pompe varies with the type of the disorder.

Classic infantile-onset Pompe is the most severe form of the disease in which symptoms appear within a few months after birth. Without treatment, affected babies often succumb to heart disease within their first year of life.

The non-classic infantile-onset form of the disease is comparatively less severe. It appears within the first year of life and has a slower progression rate, but patients often also have heart disease and breathing problems, which can be fatal if not attended to in time.

Late-onset Pompe can occur at any age. They can survive up to age 30 if the disease appears in childhood and up to age 50 if it develops in adulthood. Generally, the later the age of onset, the slower the disease progression and the longer the life expectancy.

Enzyme Replacement Therapy for Pompe can prolong survival, reverse cardiomyopathy, and improve motor function.

Patients with either type of infantile-onset Pompe may have their lives prolonged with early detection and treatment. However, if left untreated, both these types of Pompe are often fatal. Patients with classic infantile-onset type rarely live past 1 year of age. Patients with non-classic infantile-onset type may live to early childhood. Children with late-onset types of Pompe can live longer as the disease progresses more slowly.