Also known as metabolic muscle conditions, these are conditions that interfere with the way muscles provide energy.
They include:
- McArdle disease (Glycogen storage disease type V)
- Pompe disease (also known as acid maltase deficiency and glycogen storage disease type II)
- Carnitine deficiency
- Carnitine palmityl transferase deficiency
- Myoadenylate deaminase deficiency
- Glycogen storage disease of muscle
- Glycogen storage disease type III (Cori Forbes debrancher enzyme deficiency)
- Glycogen storage disease type IV (Anderson- brancher enzyme deficiency)
- Glycogen storage disease type VI (Tarui- phosphofructokinase deficiency)
Metabolic myopathies are caused by mutations in the genes involved the production of energy in skeletal muscles. The mutations generally block the chemical reactions that take place during energy production, so the muscle cells cannot work properly. In some cases, this can lead to episodes of muscle damage, causing acute kidney failure. In others, there is progressive muscle weakness.
Metabolic myopathies that affect young children tend to be the most severe and can, in some cases, be fatal. Those with a later onset tend to have less severe symptoms, and in very mild cases changes in diet and lifestyle can ease symptoms.
About 700 people in the UK have a form of metabolic myopathy.