What is Pompe disease?
Pompe disease, which affects approximately 1 in 40,000 Americans, is a genetic disorder that occurs as a result of certain mutations found in the GAA gene. Pompe disease causes high levels of glycogen, a complex sugar found at the cellular level, to accumulate. Because the body is unable to process the buildup of glycogen in people with Pompe disease, it impairs the functioning of various muscles, tissues, and organs. Pompe disease is a life-threatening condition, and there are different types that present during infancy on into adulthood.
What are the symptoms of Pompe disease?
Three major types of Pompe disease are classic infantile-onset, non-classic infantile-onset, and late-onset.
Children with infantile-onset Pompe disease usually begin to show symptoms only a few months after birth. These typically include muscle weakness, reduced muscle tone, an enlarged liver, heart problems, and breathing problems. If left untreated, these symptoms can be fatal within the first two years.
Non-classic infantile-onset Pompe disease usually becomes noticeable slightly later on, around the age of one. It can cause progressive muscle weakness and slowed motor development, and heart failure is less common compared to the classic infant type. However, children with non-classic Pompe disease may only live until early childhood.
Late-onset Pompe disease can first cause symptoms at a range of ages, from later childhood through to adulthood. Generally, this form is milder than the infant-onset forms and less likely to involve the heart. People with late-onset Pompe disease experience progressive muscle weakness, which may lead to respiratory failure.
However, there isn’t a firm consensus on terminology, and some experts use ‘late-onset’ to describe whether or not the heart is affected, rather than the age at which symptoms first appear.
What treatment options are available for Pompe disease?
A GAA-enzyme-replacement treatment, called Myozyme® (alglucosidase alfa), was approved by the FDA for Pompe disease treatment. It is administered by infusion every two weeks. While Myozyme is not a cure for the disease, it has been successful in treating some symptoms, especially in infancy, and has significantly decreased mortality rates.