What are the symptoms of muscular dystrophy?
The symptoms of muscular dystrophy can vary significantly depending on the type. But the main symptom is muscle weakness and other muscle-related issues. Each type can affect different muscles and parts of your body. Symptoms of muscular dystrophy generally get worse over time.
Muscle- and movement-related symptoms can include:
- Muscle atrophy.
- Difficulty walking, climbing stairs or running.
- Irregular walking gait (like waddling or toe walking).
- Stiff or loose joints.
- Permanent tightening of your muscles, tendons and skin (contractures).
- Spasticity.
- Muscle pain.
Other symptoms can include:
- Fatigue.
- Trouble swallowing (dysphagia).
- Heart problems, such as arrhythmia and heart failure (cardiomyopathy).
- Curved spine (scoliosis).
- Breathing issues.
- Intellectual disabilities.
- Learning disorder.
The symptoms of some types of muscular dystrophy are mild and progress slowly over time as you age. Other types cause more rapid muscle weakness and physical disability.
What causes muscular dystrophy?
Mutations (changes) in the genes that are responsible for healthy muscle structure and function cause muscular dystrophy. The mutations mean that the cells that would normally maintain your muscles can no longer fulfill this role, leading to progressive muscle weakness over time.
There are several genes — and possible genetic mutations — that play a role in muscle function. This is why there are so many different forms of muscular dystrophy.
In the majority of muscular dystrophy cases, the person inherits the genetic mutation from one or both of their biological parents.
There are three ways you can inherit muscular dystrophy, depending on the specific type:
- Recessive inheritance: This means you’ve inherited a genetic mutation that causes the condition from both of your biological parents. Some forms of limb-girdle muscular dystrophy have this inheritance.
- Dominant inheritance: This means you only need to inherit the mutated gene from one of your biological parents to develop the condition. Myotonic, facioscapulohumeral and oculopharyngeal muscular dystrophies have this type of inheritance.
- Sex-linked (X-linked) inheritance: A genetically male person has one X and one Y chromosome, and a genetically female person has two X chromosomes. A genetic mutation on the X chromosome causes a sex-linked condition. As genetically male people only have one copy of each gene on the X chromosome, they’ll develop the condition if one of those genes is mutated. A genetically female person can have X-linked disorders, but the symptoms are usually less severe. duch*enne and Becker muscular dystrophies have this type of inheritance.
In rare cases, a person may develop muscular dystrophy spontaneously, meaning the mutation happened randomly and wasn’t inherited. This is called a de novo mutation.
