Pompe disease is an inherited gene mutation condition affecting 1 in every 40,000 people in the United States. This debilitating disease hinders cells, especially those in the heart muscle, from functioning normally. Children who inherit this condition can suffer from heart and breathing problems as well as muscle weakness elsewhere in the body, making it difficult to walk.
The glucosidase alpha acid (GAA) gene regulates an enzyme known as acid alpha-glucosidase. This enzyme, also known as acid maltase, is broken down within a cell, inside the lysosomes.
The National Institute of Health describes lysosomes as the recycling centers inside cells. In a healthy cell, various enzymes reduce complex molecules into simple chemicals that can be used by cells. The acid maltase enzyme is responsible for breaking down the complex sugar, glycogen, into a simple sugar, glucose. Glucose is then used as energy for the cell.
Pompe disease causes mutations in the GAA gene so that acid alpha-glucosidase enzymes can’t break down the glycogen fast enough to prevent sugar build-up. Toxic levels of sugar in the lysosomes damages organs and tissues, the muscles, in particular.
The National Institute of Neurological Disorders (NIND) categorizes Pompe disease as early onset or late onset. Early onset occurs in infancy and is a result of GAA deficiency.
During the first months, the baby will experience poor weight gain and difficulty feeding, an enlarged tongue, muscle weakness and head lag. The heart is also enlarged and many of these babies pass away before their first birthday.
The later onset of Pompe disease is cause by partial GAA deficiency. A person can be as young as 10 years old or as old as 60 when late onset symptoms are first noticed. While the heart muscle is usually not affected, late onset includes muscle weakness, occurring over several years, leading to eventual death from respiratory failure.
According to NIND, the diagnosis for Pompe disease is confirmed by a blood sample to measure for GAA enzymes or through genetic mutation screenings.
The Muscular Dystrophy Association reminds us that today the odds are improving for these children. In 2006, the U.S. Food and Drug Administration approved a drug which has extended the lives of babies with early onset Pompe disease.
For older children with this disease, odds are even better. These kids are living longer, into adulthood, with the help of neurologists, cardiologists, and respiratory therapists.
Sources:
Genetics Home Reference. GAA. Web. 21, Dec. 2011.
http://ghr.nlm.nih.gov/gene/GAA
National Institute of Neurological Disorders and Stroke. Pompe Disease. Web. 21, Dec. 2011.
http://www.ninds.nih.gov/disorders/pompe/pompe.htm
Muscular Dystrophy Association. Acid Maltase Deficiency. Web. 21, Dec. 2011.
http://www.mda.org/disease/amd.html
Reviewed December 22, 2011
by Michele Blacksberg RN
Edited by Jody Smith