Muscular dystrophy

The muscular dystrophies (MD) are a group of inherited genetic conditions that gradually cause the muscles to weaken. This leads to an increasing level of disability.

MD is a progressive condition, which means that 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 is no cure for MD, but treatment can help manage many of the symptoms.

Why it happens

MD is caused by changes (mutations) in the genes responsible for the structure and functioning of a person's muscles.

These 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 there is a known family history of MD, your GP may be able to refer you for genetic testing and counselling to evaluate the risk that you might develop the condition or have a child with MD, and to discuss the options available to you.

Read more about the causes of MD and genetic testing for MD.

Types of muscular dystrophy

There are many different types of MD, each with somewhat different symptoms. Not all types of MD cause severe disability and many do not affect life expectancy.

Some of the more common types of MD include:

Duchenne muscular dystrophy – 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 is not always affected, but people with a severe form of it may have shortened lives
facioscapulohumeral muscular dystrophy – a type of MD that can develop in childhood or adulthood, it progresses slowly and is not usually life threatening
Becker muscular dystrophy – closely related to Duchenne MD, but it develops later in childhood and is less severe; life expectancy is not usually affected so much
limb-girdle muscular dystrophy – a group of conditions that usually develop in late childhood or early adulthood; some variants can progress quickly and be life threatening, whereas others only develop slowly
oculopharyngeal muscular dystrophy – a type of MD that usually doesn't develop until a person is 50-60 years old and doesn't tend to affect life expectancy
Emery-Dreifuss muscular dystrophy – a type of MD that develops in childhood or early adulthood; most people with this condition will live until at least middle age

Read more about the types of MD and diagnosing MD.

Who is affected?

More than 70,000 children and adults in the UK have MD or a related condition.

Duchenne MD is the most common type of MD and affects around one boy in every 3,500 in the UK. The second most common type is myotonic MD, which affects around one person in every 8,000.

Facioscapulohumeral MD is believed to affect around 1 in every 20,000 people in the UK, which would make it the third most common type.

Treating muscular dystrophy

Although there is no cure for MD, a range of treatments can help with the physical disabilities and problems that may develop. These can include:

mobility assistance, including exercise, physiotherapy and physical aids
support groups to help deal with the practical and emotional impact of MD
surgery to correct postural deformities such as scoliosis
medication such as steroids to improve muscle strength, or ACE inhibitors and beta-blockers to treat heart problems

New research is looking into ways of repairing the genetic mutations and damaged muscles associated with the condition. There are currently promising clinical trials for Duchenne MD. Search for clinical trials for muscular dystrophy.