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Pompe disease

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 glucosidase acetate,
  • Lack of Acetate Maltase (AMD),
  • Type II glycogen storage disease (GSD),
  • Glucogenesis 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 α-glucosidase acetate 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 or partially deficient, resulting in glycogen not breaking apart and leaking into the muscle cells by destroying them.

Although it is a hereditary disease, the 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 of symptoms, 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, it is 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 α-glucosidase acetate 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 examinations 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:

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

Patient groups 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... and https://clinicaltrials.gov/ct2/home

 

References

Muscular Dystrophy Association