Pompe Disease [E74.0]
Dipl.-Biol. Christine Nitsch, Dipl.-Biol. Birgit Busse
Pompe disease (also known as glycogen storage disease type II) is an autosomal recessive inherited disease belonging to the group of lysosomal storage diseases.
Through reduced activity of the enzyme 1,4-α-Glucosidase (GAA, acid maltase) , there is disruption in the glycogen breakdown in the lysosomes. This is caused by mutations in the GAA gene.
The enzyme defect causes a progressive, systematic accumulation of glycogen in the lysosomes, in particular in cells of the heart and muscles.
There are two types of Pompe diseases, grouped according to the first symptoms: in the infantile form, a homogenous clinical presentation with pronounced muscle weakness (floppy infants), respiratory insufficiency and development delays is seen. If untreated, most children will die from cardiac failure within the first year of life.
In the late-onset form, the course is extremely variable and the classification to other muscular disorders difficult. Symptoms can include progressive muscle weakness especially of the torso muscles, back pain, scoliosis, dyspnea, sleep apnea, morning headaches and daytime sleepiness.
Before molecular genetic testing of the GAA gene, the enzyme activity of 1,4-α-Glukosidase should be determined.
The disease is inherited in an autosomal recessive pattern, i.e. both alleles must be affected for clinical expression of the enzyme deficiency. It is a rare disease with a worldwide incidence of approximately 1:40,000. The possibility of enzyme replacement therapy in addition to symptomatic treatment has existed in Europe since 2006.