Pompe disease treatment by Ray Sahelian, M.D.
January 20 2016

 

Pompe disease or glycogen storage disease type II is a hereditary metabolic myopathy caused by the complete or partial deficiency of the enzyme acid alpha-glucosidase (also known as lysosomal alpha-glucosidase or acid maltase). This enzyme deficiency causes excess amounts of glycogen to accumulate in the lysosomes of many cell types but predominantly in muscle cells. The resulting cellular damage manifests as muscle weakness and/or respiratory difficulty.
     Generalised muscle weakness combined with an enlarged heart presents within the first few months after birth, if the lysosomal alpha-glucosidase (AGLU) deficiency is complete. Residual enzyme activity prevents cardiac involvement and delays onset of muscle weakness. Enzyme therapy, by intravenous administration of acid AGLU, aims to supplement the missing enzyme activity.

 

Enzyme replacement therapy

Enzyme replacement therapy (ERT) for lysosomal storage diseases did not become a reality until the early 1990s when its safety and effectiveness were demonstrated in type 1 Gaucher disease. Today, ERT is a reality for Gaucher disease, Fabry disease and mucopolysaccharidosis type I (MPS I), and clinical trials with recombinant human enzymes are ongoing in Pompe disease, MPS II and MPS VI, and are about to begin in Neimann-Pick B disease.

 

Brain Nerve. 2015. Enzyme Replacement Therapy for Pompe Disease: The Long-Term Efficacy and Limitation. The long-term efficacy of enzyme replacement therapy (ERT) in patients with Pompe disease has been unraveled. Cardiac muscle responds well to ERT, whereas motor and respiratory functions do not. The screening of newborns, which enables the early initiation of ERT, has improved outcomes of infantile Pompe patients. Myopathies still exist even in patients in whom ERT is initiated early, and have become recognized as an emerging new phenotype of IP on ERT.

 

New medication for Pompe disease

Myozyme (alglucosidase alfa, Genzyme) was approved by the FDA for the treatment of patients with Pompe disease in June 2006.

 

Diagnosis
JAMA Neurol. 2013. Diagnosis of Pompe disease: muscle biopsy vs blood-based assays. The diagnosis of Pompe disease (acid maltase deficiency, glycogen storage disease type II) in children and adults can be challenging because of the heterogeneous clinical presentation and considerable overlap of signs and symptoms found in other neuromuscular diseases. This review evaluates some of the methods used in the diagnosis and differential diagnosis of late-onset Pompe disease. Muscle biopsy is commonly used as an early diagnostic tool in the evaluation of muscle disease. However, experience has shown that relying solely on visualizing a periodic acid-Schiff-positive vacuolar myopathy to identify late-onset Pompe disease often leads to false-negative results and subsequent delays in identification and treatment of the disorder. Serum creatine kinase level can be normal or only mildly elevated in late-onset Pompe disease and is not very helpful alone to suggest the diagnosis, but in combination with proximal and axial weakness it may raise the suspicion for Pompe disease. A simple blood-based assay to measure the level of α-glucosidase activity is the optimal initial test for confirming or excluding Pompe disease. A timely and accurate diagnosis of late-onset Pompe disease likely will improve patient outcomes as care standards including enzyme replacement therapy can be applied and complications can be anticipated. Increased awareness of the clinical phenotype is therefore warranted to expedite diagnostic screening for this condition with blood-based enzymatic assays.

 

Pompe disease research

Physical therapy management of Pompe disease.
Genet Med. 2006.
Pompe disease, or acid maltase deficiency, is an autosomal recessive disorder characterized by deficiency of acid alpha-glucosidase resulting in intra-lysosomal accumulation of glycogen and leading to progressive muscle dysfunction. The natural history of infantile-onset Pompe disease is characterized by hypertrophic cardiomyopathy and profound generalized weakness presenting in the first few months of life, with rapid progression and death usually occurring by one year of age. Late-onset Pompe disease is characterized by onset of symptoms after one year of age, less severe or absence of cardiac involvement and slower progression, with symptoms primarily related to progressive dysfunction of skeletal muscles and respiratory muscle involvement. Recent clinical trials of enzyme replacement therapy have begun to allow greater opportunity for potential improvement in motor status, function, and survival than ever before, with hopes of moving toward maximizing physical function for individuals with Pompe disease. Children are living longer with some achieving independent sitting, creeping, and walking-milestones typically never achieved in the untreated natural history of the disorder.

 

Questions
Do you think lipoic acid is helpful in Pompe disease? What about CoQ10?
   I couldn't even guess, I have no idea.

 

My 10 year old daughter has deficiency in her level of maltase enzymes. I am looking for a supplement to assist with that. Do you have any suggestions?
   At this time I don't.