Pompe Disease

Pompe disease is caused by a genetic mutation that causes a buildup of complex sugars in the body’s tissues. This buildup makes it difficult for children with the disease to function normally. Pompe disease, sometimes referred to as glycogen storage disease type II, is one of nearly 50 diseases classified as lysosomal storage disorders (LSD).

Lysosomes contain specific proteins (enzymes) that are responsible for breaking down and recycling molecules such as fats and sugars. Individuals with a lysosomal storage disorder lack one of these necessary enzymes or do not have one of these enzymes in sufficient quantities to break down molecules for proper cell function.

There are two types of Pompe disease: infantile Pompe disease and late-onset Pompe disease.

Symptoms of infantile Pompe disease appear during infancy. Infantile Pompe disease is further categorized as either classic or non-classic. When a child has infantile Pompe disease, symptoms appear shortly after birth. With non-classic infantile Pompe disease, symptoms appear later but generally within the first year of life.

Symptoms may include:

• Muscle weakness (myopathy)
• Poor muscle tone (hypotonia)
• Enlarged liver (hepatomegaly)
• Heart defects
• Poor growth and poor weight gain (failure to thrive)
• Respiratory difficulties

If left untreated, classic infantile Pompe disease can lead to heart failure within the first year of life.

Symptoms of late-onset Pompe disease appear later in life, generally in late childhood, adolescence, or even adulthood.

Symptoms may include:

• Progressive muscle weakness (myopathy)
• Muscle cramping
• Extreme fatigue
• Gait abnormality
• Mobility difficulties
• Respiratory difficulties

Pompe disease is caused by a mutation in the GAA gene, which leads to a deficiency in a specific protein — an enzyme called acid maltase. Mutations in the GAA gene keep acid maltase from properly breaking down complex sugars within the body’s cells. Pompe disease is caused by an accumulation of these sugars and other molecules in the body’s organs and tissues, particularly in muscles. This genetic condition is inherited in an autosomal recessive pattern, which means that an affected child has received one defective copy of the GAA gene from each of their parents.

Current approaches to all types of Pompe disease are tailored to specific patients and may include enzyme replacement therapy (ERT), and additional supportive therapies that target specific symptoms and complications of the disease. Treatment plans require interdisciplinary collaboration and depend greatly on a patient’s specific disease presentation.

At the Boston Children’s Lysosomal Storage Disorders (BoLD) Program, our team of providers is committed to the care of complex patients. As part of Boston Children’s Hospital, we are prepared to meet the challenge of providing multifaceted care by partnering with you and your child to deliver direct care in our BoLD clinic. We work with the broad array of world-class specialists at Boston Children’s to optimize the care we provide your child with Pompe disease.