Pompe disease

It is a rare neuromuscular disease that occurs in infants, children or adults who have inherited mutated genes from the parents in an autosomal recessive pattern. It evolves progressively, causing muscle weakness and often breathing problems.

It is also considered a metabolic disease because it is caused by total or partial deficiency of the lysosomal α-glucosidase acetate enzyme.

It is also known as:

  • Lack of acetate glucosidase,
  • Lack of Acetate Maltase (AMD),
  • Type II glycogen storage disease (GSD),
  • Glucogenοsis II,
  • Lack of lysosomal α-glucosidase.

It has been calculated to occur at a frequency of 1: 40,000 births, affecting men and women equally.

Causes

It is caused by a mutation in the gene responsible for the production of acetate α-glucosidase of lysosomes, ie cell organelles. This enzyme is naturally responsible for the breakdown of glycogen, a form of stored glucose in the cells, which gives them energy. In Pompe patients it is either completely absent or partially deficient, resulting in glycogen not breaking apart and leaking into the muscle cells destroying them.

Although it is a hereditary disease, onset of symptoms occurs at any age until adulthood. Generally, there is a great deal of heterogeneity in the rate of progression of the disease and the extent to which it affects other organs. The earlier the onset, the more severe the disease progress, especially at neonatal age, accompanied by complete lack of enzyme.

Symptoms

When these occur in the first months of life, they are rapidly developed  leading to death due to heart failure. When these occur later in time, they cause muscle weakness throughout the body, but mainly respiratory and motor muscles are impaired.

Main symptoms in neonates

  • Severe muscle weakness.
  • Imbalance.
  • Unable to rotate, walk, lift, support of the head.
  • Breathlessness.
  • Common respiratory infections.
  • Respiratory insufficiency.
  • Feeding and ingestion problems.
  • Hepatomegaly, enlarged tongue.
  • Inability to gain weight.
  • Frequent vomiting, regurgitation.
  • Heart problems.

Main symptoms in children and adults

  • Gradual occurrence of muscle weakness in legs and hips, as well as loss of walking.
  • Difficulty climbing on stairs, running or lifting from a chair.
  • Walk with support.
  • Loss of balance with frequent falls.
  • Lumbar pain.
  • Scoliosis.
  • Difficulty breathing – frivolous breaths.
  • Headaches, drowsiness.
  • Common respiratory infections (bronchiolitis, pneumonia).
  • Inability to gain weight.
  • Chewing and swallowing problems.

Diagnosis

  • Enzyme measurements of acetate α-glucosidase in skin, muscle and blood samples.
  • Blood tests and CK enzyme assay (to exclude other neuromuscular diseases).
  • Electromyography.
  • Electrocardiogram.
  • Heart ultrasound (echo cardiogram).
  • Chest X-ray.

Management

Physiotherapy, occupational therapy, speech therapy, psychotherapy, nutritional support by specialists, genetic counseling and of course cardiac and respiratory care and frequent tests are suggested. Enzyme replacement therapy (ERT) with Myozyme in the case of Pompe disease is now available as a treatment, where intravenously a form of human α-glucosidase acetic enzyme is administered which, as soon as possible, delays the progression of the disease. Additional research efforts and various clinical trials are being undertaken in pre-clinical gene therapy.

For more information about the disease and search fields, you can visit the following websites:

CONSENSUS TREATMENT RECOMMENDATIONS FOR LATE-ONSET POMPE DISEASE

Patient groups

International Pompe Association (IPA): www.worldpompe.org

Maltase Deficiency Acid Association (AMDA): www.amda-pompe.org

The Pompe’s Group of the Association for Glycogen Storage Group: www.agsd.org.uk

United Pompe Foundation (UPF): www.unitedpompe.com

Information about clinical trials conducted globally: https://www.centerwatch.com/clinical-trials/listings/condition/756/pompe-disease/ and https://clinicaltrials.gov/ct2/home

References

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