The symptoms of muscular dystrophy (MD) and their severity will vary from person to person depending on the type of MD they have.
Typical symptoms of some of the most common types of MD are explained below. The Muscular Dystrophy Campaign also provides a list of specific neuromuscular conditions.
Duchenne muscular dystrophy
Your child will usually start to show signs of Duchenne MD at 1-3 years of age. The muscles around their pelvis and thighs tend to be affected first and often appear bulkier than normal, even though there is progressive weakening. Your child may:
- have difficulty walking
- have difficulty standing up
- be unable to climb the stairs without support
- have behavioural or learning difficulties
Children with Duchenne MD may need a wheelchair by the age of 10. They can also develop scoliosis, in which their spine begins to curve sideways. This can lead to one shoulder or hip being higher than the other.
By the mid-teens, some people with Duchenne MD will develop dilated cardiomyopathy. This is where the condition affects the heart muscles, causing the chambers of the heart to enlarge and the heart walls to become thinner.
By late teens or early twenties Duchenne MD can begin to cause respiratory (breathing) problems. The condition can affect the intercostal muscles (muscle tissue between the ribs) and the diaphragm (the main muscle between the chest and the abdomen that is used during breathing).
Once the heart and respiratory muscles are damaged, Duchenne MD becomes life-threatening. In most cases, someone with Duchenne MD will die from heart or respiratory failure before they are 30 years old.
Becker muscular dystrophy
The symptoms of Becker MD are similar to those of Duchenne muscular dystrophy. However, they are milder and do not usually appear until a person is at least 10 or 11 years old. If your child has Becker MD, they may:
- be late learning to walk
- have muscle cramps when exercising (a painful spasm in the muscle)
- struggle with sport at school
The rate at which someone with Becker MD develops symptoms is very variable. Affected individuals will often first find that they have difficulty running, walking quickly and climbing stairs. As they get older, they may find it difficult to lift objects above waist height. They will often eventually require a wheelchair by 40-50 years old, but this may be much earlier or later.
If you have Becker MD, you are also at risk of developing dilated cardiomyopathy and respiratory problems. However, Becker MD progresses more slowly than Duchenne MD, and those with the condition often have a normal lifespan.
Myotonic muscular dystrophy
As with other types of muscular dystrophy, myotonic MD involves progressive muscle weakness and muscle wasting. However, it is often the smaller muscles, such as those in the face, jaw, neck and hands, and lower legs that are affected first.
As well as muscle weakness and wasting, symptoms can include:
- myotonia (muscle stiffness)
- cataracts (cloudy patches in the lens inside the eye)
- hormonal problems
- excessive sleeping or sleepiness
- behavioural problems in children
Myotonic MD can also cause slow and irregular heart beats (cardiac arrhythmia). Serious problems can develop in about 60-70% of people who have these abnormalities. In some cases, it can cause sudden death.
Myotonic MD can appear at any time between birth and old age. It affects the same number of men and women. The rate of deterioration is often very slow, with little change over a long period of time. Someone with myotonic MD may never have significant disability, although their heart rate will need to be monitored for abnormalities.
Limb-girdle muscular dystrophy
The symptoms of limb-girdle MD often begin during late childhood or early adulthood. There are about 15 varieties that affect both sexes equally.
Limb-girdle MD causes weakness in the big muscle groups in the arms and legs. The first symptoms are often mobility problems affecting the hip girdle. It then progresses to the shoulder girdle (‘girdle’ means the bones around the shoulder or hip).
If you have limb-girdle MD, you may experience:
- muscle weakness in your hips, thighs and arms
- loss of muscle mass in the affected areas
- back pain
- heart palpitations or irregular heart beats
The muscle weakness will create problems such as:
- difficulty getting out of a low seat
- difficulty lifting objects
- difficulty running
Limb-girdle MD can progress at different rates as it is a group of conditions rather than one single disorder. Some people may be affected in a similar way to boys with Duchenne MD, but more often it has a pattern similar to Becker MD.
Facioscapulohumeral muscular dystrophy
Facioscapulohumeral MD can affect men and women. It tends to affect men slightly more than women, although the reason for this is unclear. The condition usually develops between 10 and 40 years of age, and it progresses slowly.
Symptoms in your child may include:
- they sleep with their eyes slightly open
- they cannot squeeze their eyes tightly shut
- they cannot purse their lips (for example, to blow up balloons)
Teenagers or adults may have aches in their shoulders, rounded shoulders or thin upper arms. As the condition progresses, it usually affects the muscles:
- in the face (facio)
- in the shoulders (scapula)
- in the upper arms (humeral)
- in the upper back
- in the calves
Around 50% of people with facioscapulohumeral MD develop weakness in their leg muscles. Between 10 and 20% of people will need a wheelchair.
Facioscapulohumeral MD can develop unevenly, so that the muscles on one side of the body may be affected more than the other. Some people may not even be aware that they have the condition until they reach old age. The slow progression means that it does not usually shorten life expectancy.
Oculopharyngeal muscular dystrophy
In oculopharyngeal MD, symptoms are not usually apparent until a person is around 50 or 60 years old, although the abnormal gene that causes the condition will have been present since birth. It affects the muscles in the eyes (ocular) and the throat (pharyngeal).
Symptoms of oculopharyngeal MD can include:
- ptosis (droopy eyelids)
- dysphagia (difficulty swallowing)
- progressive restriction of eye movement as the eye muscles are affected
- limb weakness around the shoulders and hips
As the eyelids droop, they can cover the eyes and impair vision. It is also possible to develop diplopia (double vision).
The dysphagia can eventually make it hard to swallow solid foods and liquids, and even small amounts of saliva. However, with treatment to manage the symptoms, a person’s life expectancy is not usually altered.
