The muscular dystrophies (MD) are a group of inherited genetic conditions that gradually cause the muscles to weaken, leading to an increasing level of disability.
MD is a progressive condition, which means it gets worse over time. It often begins by affecting a particular group of muscles, before affecting the muscles more widely. Some types of MD eventually affect the heart or the muscles used for breathing, at which point the condition becomes life-threatening.
There’s no cure for MD, but treatment can help to manage many of the symptoms.
What causes muscular dystrophy?
MD is caused by changes (mutations) in the genes responsible for the structure and functioning of a person’s muscles.
The mutations cause changes in the muscle fibres that interfere with the muscles’ ability to function. Over time, this causes increasing disability.
The mutations are often inherited from a person’s parents. If you have a family history of MD, your GP may refer you for genetic testing and counselling to evaluate your risk of developing the condition or having a child with MD, and to discuss the options available to you.
Types of muscular dystrophy
There are many different types of MD, each with somewhat different symptoms. Not all types cause severe disability and many don’t affect life expectancy.
Some of the more common types of MD include:
- Duchenne MD – one of the most common and severe forms, it usually affects boys in early childhood; men with the condition will usually only live into their 20s or 30s
- Myotonic Dystrophy – a type of MD that can develop at any age; life expectancy isn’t always affected, but people with a severe form of myotonic dystrophy may have shortened lives
- Facioscapulohumeral MD – a type of MD that can develop in childhood or adulthood; it progresses slowly and isn’t usually life-threatening
- Becker MD – closely related to Duchenne MD, but it develops later in childhood and is less severe; life expectancy isn’t usually affected as much
- Limb-Girdle MD – a group of conditions that usually develop in late childhood or early adulthood; some variants can progress quickly and be life-threatening, whereas others develop slowly
- Oculopharyngeal MD – a type of MD that doesn’t usually develop until a person is 50-60 years old, and doesn’t tend to affect life expectancy
- Emery-Dreifuss MD – a type of MD that develops in childhood or early adulthood; most people with this condition will live until at least middle-age