Muscular dystrophy refers to a group of genetic conditions that cause gradual weakening and wasting of muscles.
Duchenne muscular dystrophy is the most common type in children. Other types include:
- Becker muscular dystrophy
- Myotonic dystrophy
- Facioscapulohumeral muscular dystrophy
- Oculopharyngeal muscular dystrophy
- Limb-girdle muscular dystrophy
- Emery-Dreifuss muscular dystrophy
Duchenne Muscular Dystrophy
Duchenne muscular dystrophy is caused by a faulty gene on the X chromosome that makes dystrophin, a protein that helps hold muscles together at the cellular level. The condition is inherited in an X-linked recessive pattern.
Since males have only one X chromosome, a faulty dystrophin gene will cause the disease. Females have two X chromosomes, so if only one is affected, they are usually carriers and do not have symptoms.
A female carrier has a 50% chance of passing the faulty gene to each child. Sons who inherit the gene will develop Duchenne muscular dystrophy, and daughters who inherit it will become carriers.
Boys typically present with pelvic muscle weakness at ages 2-5 years. The weakness tends to be progressive, and eventually most muscles will be affected. They usually require a wheelchair by the age of 10-13. Life expectancy is around 25-35 years with good management of cardiac and respiratory complications.
Oral steroids may slow the progression of muscle weakness.
Becker Muscular Dystrophy
Becker muscular dystrophy is similar to Duchenne, except that the dystrophin gene is less severely affected and maintains some of its function. Age of symptom onset is variable, ranging from late childhood to adulthood, with a mean age of 11 years. Some patients require wheelchairs in their late 20s or early 30s, while others can walk with assistance into later adulthood.
Myotonic Dystrophy
Myotonic dystrophy is an autosomal dominant genetic condition that usually presents in adulthood. Typical features are:
- Progressive muscle weakness
- Prolonged muscle contractions
- Cataracts
- Cardiac arrhythmias
- Frontal balding
- Testicular atrophy and infertility
- Endocrine dysfunction
TOM TIP: The key feature of myotonic dystrophy to remember is the prolonged muscle contraction. This may present in exams as a patient who is unable to let go after shaking someone’s hand or to release their grip on a doorknob after opening a door. During an upper-limb neurological examination, shake the patient’s hand and observe for difficulty releasing the grip.
Facioscapulohumeral Muscular Dystrophy
Facioscapulohumeral muscular dystrophy usually presents in childhood or adolescence with weakness around the face, progressing to the shoulders and arms. A classic initial symptom is sleeping with their eyes slightly open and weakness in pursing their lips. They are unable to blow their cheeks out without air leaking from their mouth.
Oculopharyngeal Muscular Dystrophy
Oculopharyngeal muscular dystrophy usually presents in late adulthood with weakness of the ocular muscles (around the eyes) and the pharynx (around the throat). A typical presentation is with bilateral ptosis and swallowing difficulties. Limb-girdle weakness typically appears later.
Limb-girdle Muscular Dystrophy
Limb-girdle muscular dystrophy usually presents in teenage years with progressive weakness around the limb girdles (hips and shoulders).
Emery-Dreifuss Muscular Dystrophy
Emery-Dreifuss muscular dystrophy usually presents in childhood with contractures, most commonly in the elbows and ankles. Contractures are shortening of muscles and tendons that restrict the range of movement in limbs. Patients also suffer from progressive weakness and wasting of muscles, starting with the upper arms and lower legs. Cardiac conduction defects and arrhythmias are key complications.
Gower’s Sign
Gower’s sign refers to the technique used by children with proximal muscle weakness to stand from a lying position.
They get onto their hands and knees, then push their hips back and up into the “downward dog” pose. They then shift their weight back and place their hands on their knees. Whilst keeping their legs mostly straight, they walk their hands up their legs to straighten their upper bodies. They do this because hip extensors and proximal lower-limb muscles are not strong enough to get their upper body erect without the help of their arms.
TOM TIP: Gower’s sign is a favourite in exams. If a 5 year old boy is presenting with vague symptoms of muscle weakness, and the description is that you notice them using their hands on their legs to help them stand up, the answer is probably Duchenne muscular dystrophy. They may ask, “What is the underlying genetic inheritance of the most likely cause?” The answer is X-linked recessive.
Management
There is no curative treatment for muscular dystrophy. Management aims to enable the person to have the highest possible quality of life for as long as possible. This usually involves input from occupational therapy, physiotherapy and medical appliances (such as wheelchairs and braces) as well as surgical and medical management of complications such as spinal scoliosis and heart failure.
Last updated February 2026
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