Muscular dystrophy (MD) is a genetic condition that causes mutations in muscle fibres that progressively weaken the muscles. Over time, the decreasing muscle function results in an increasing level of disability. Some types of MD will eventually affect the ability to swallow, as well as weakening the heart and respiratory muscles.
In the UK, around 70,000 babies, children and adults are impacted by MD. Fewer women and girls are affected than men and boys, and their condition is generally less severe.
As yet there is no cure for MD. There are however a variety of treatments depending on the type and severity of MD. These include physiotherapy and exercises, physical aids to help people stay mobile, pacemakers, and steroid medication, as well as corrective surgery to ease some of the physical effects, such as postural positioning, scoliosis, difficulty swallowing, and drooping eyelids.
The prognosis for those with MD differs according to the type and progression of the disorder. Some cases may be mild and progress slowly over a normal lifespan. Others produce severe muscle weakness, functional disability, and loss of the ability to move parts of the body. Some children with MD die in infancy while others live into adulthood with only moderate disability. MD can affect adults at any age, but the more severe forms tend to occur in early childhood.
Research is ongoing, and there are new trials with gene therapy, as well as promising research into stem cell therapies.
There are different types of MD, each with different symptoms and severity of disability. Some types are inherited, while others occur without warning. Not all types affect life expectancy.
The most common form is Duchenne Muscular Dystrophy (DMD), which is considered the most severe as it is a life-limiting condition. DMD usually affects boys and is typically diagnosed when they are between 1 and 3 years old. While DMD does occasionally affect girls, their condition is generally milder. Young people with DMD usually need to use a wheelchair by their mid-teens, and the condition can also lead to scoliosis. Eventually the condition damages the heart and respiratory muscles, and most people die of heart failure or respiratory failure in their early 30s. The rarer Becker MD is closely related to DMD, but it develops later in childhood and is less severe.
Myotonic is the second most common type of MD. It can develop at any age and affects men and women equally. It’s usually first detected in the face, neck, arms, hands, hips and lower legs. Life expectancy isn't always affected unless the condition is severe.
The third most common type is Facioscapulohumeral MD, which can also develop at any age and affects both genders equally. Muscle weakness is usually first detected in the face, shoulders and upper arms. It isn’t usually life-threatening and progresses slowly.
Why do some MD variants affect males more than females?
Some disorders are caused by a genetic mutation in the X chromosome. Men have only one X chromosome (the other being a Y), whereas women have two. If one X chromosome is mutated, women have another that will compensate for the mutated one. As men do not have that ‘back up’ X chromosome, they are more severely affected.
For more information about the causes, symptoms and treatments of Muscular Dystrophy, click the links below: