More than 30 types of muscular dystrophy have been identified. They all cause problems with movement due to muscle protein defects caused by genetic mutations.
Muscular dystrophy is a group of inherited genetic conditions that cause progressive muscle weakness and often disability.
All types of muscular dystrophy are rare. Combined, they’re estimated to affect
Congenital muscular dystrophies, which describe all the types present at birth or shortly after birth, occur in slightly fewer than
Let’s examine the most common subtypes of muscular dystrophy.
Duchenne muscular dystrophy is the most common type of muscular dystrophy and one of the most severe. It’s caused by a recessive gene mutation on the X chromosome.
About
The signs and symptoms, which generally appear in the first several years of life, can include:
- intellectual disability
- trouble walking, often first noticeable between ages 2 and 3 years
- enlargement of calves with wasting of thigh muscles
- fatigue
- slow motor development
- cardiomyopathy
- rapidly progressing weakness in your:
- legs
- pelvis
- arms
- neck
The outlook for Duchenne muscular dystrophy is typically unfavorable, and most people with the condition need to use a wheelchair by age 12. Most people with this type of muscular dystrophy do not live past their 20s due to heart or lung issues.
Becker muscular dystrophy is caused by a recessive mutation on the X chromosome. “Recessive” means that the condition develops only if you receive the mutated gene from both parents. This type occurs almost exclusively in males and affects roughly
Symptoms can begin at any time from 5 to 60 years old. Some people with this condition can continue to walk until old age. Symptoms may include:
- muscle weakness starting in your thighs
- cramping with strenuous activity
- cognitive impairment
- delayed ability to run, jump, or climb stairs
- enlarged calves
- heart problems
People with Becker muscular dystrophy typically live to be 40–50 years old. Death usually occurs due to dilated cardiomyopathy.
Myotonic muscular dystrophy is the most common type of muscular dystrophy that begins in adulthood. It’s caused by autosomal dominant mutations in the DMPK or CNBP gene. “Autosomal” means the gene is located on one of the chromosomes, not related to sex. “Dominant” means that you need to receive the gene from only one parent rather than both.
Myotonia is slowed relaxation after a normal muscle contraction. It’s commonly called muscle stiffness.
Myotonic muscular dystrophy generally affects about
Severity can range from fatal in infancy to mild with no symptoms until late adulthood. It usually causes muscle weakness and an inability to relax the smaller muscles in your:
- hands
- face
- neck
It can also cause symptoms such as:
- muscle stiffness
- cataracts
- slow and irregular heartbeat
- bowel problems
- slurred speech
- behavioral and personality problems
An earlier age of onset is linked to a less favorable outcome and decreased survival. About
Limb-girdle muscular dystrophy is a group of muscular dystrophies that cause weakness primarily around your upper limbs, though it also affects your pelvic girdle (midsection) muscles. It occurs in 1 in 44,000–123,000 people. It can be inherited through more than 25 recessive or dominant genes.
Limb-girdle muscular dystrophy can start in childhood and cause symptoms that resemble those of Duchenne muscular dystrophy. But symptoms may not develop until adulthood and may progress slowly.
The outlook is highly variable between people. Some people maintain the ability to walk and may need to use a wheelchair only later in life.
Facioscapulohumeral muscular dystrophy (FMD) primarily causes muscle weakness and wasting of the muscles in your:
- face
- shoulders
- upper arms
- lower legs
- pelvic girdle
FMD is inherited through a dominant mutation in the DUX4 gene. It’s thought to occur in about 4 to 10 in 100,000 people.
Symptoms usually start before age 20 but can begin later. FMD generally does not shorten life expectancy. Roughly
Emery-Dreifuss muscular dystrophy (EDMD) causes:
- reduced range of motion in joints in early childhood
- slowly progressing muscular weakness
- muscle wasting starting in your upper arms and calves and later extending to your upper legs and shoulders
EDMD is usually caused by a dominant gene mutation on the X chromosome. It’s estimated to affect about 1 in 400,000 people.
The outlook varies, but many people live until middle age or later.
Distal muscular dystrophy is a group of conditions that cause progressive weakness in your:
- hands
- forearms
- lower legs
- feet
Many gene mutations can cause distal muscular dystrophy. The outlook varies widely between subtypes.
Oculopharyngeal muscular dystrophy symptoms usually appear between the ages of 40 and 60 years. It primarily causes progressive weakness of the muscles around your eyes and throat.
The most common initial symptoms are drooping eyelids and trouble swallowing.
Oculopharyngeal muscular dystrophy can be caused by dominant or recessive genes. It usually does not affect life expectancy.
Collagen type VI-related disorders can be inherited through dominant or recessive genes.
Symptoms range from mild to severe. People with severe forms may never be able to run, jump, or climb stairs without using a railing. While people with mild forms may remain independent for life.
Doctors use a variety of tests to diagnose muscular dystrophy, rule out other conditions, and monitor side effects. Possible tests include:
- a physical exam
- blood tests
- muscle biopsies
- genetic tests
- nerve conduction studies
- imaging tests such as:
Treatment options include:
- low impact exercise
- physical and occupational therapy
- mobility devices, such as a wheelchair or braces
- corticosteroids
- gene therapy for Duchenne muscular dystrophy, with drugs such as ataluren (Translarna), eteplirsen (Exondys 51), and golodirsen (Vyondys 53)
- creatine supplements
- treatments for swallowing problems, such as surgery
- ACE inhibitors for heart problems
- surgery to address postural irregularities
Muscular dystrophy is usually caused by inherited gene mutations. In rare cases, these mutations can develop without a family history.
More than 30 types of muscular dystrophy have been identified. They’re classified based on factors such as:
- age of onset
- symptoms
- associated genes
- severity
The most common type of muscular dystrophy is Duchenne muscular dystrophy.
Myotonic dystrophy is the most common type of muscular dystrophy that begins in adulthood.
Oculopharyngeal muscular dystrophy is one of the rarest types. It affects less than 1 in 100,000 people (0.13 in 100,000).
Muscle dystrophy is a genetic condition that causes progressive muscular weakness. Muscular atrophy is the loss of muscle mass. Atrophy can have many causes, including inactivity and a genetic condition called spinal muscular atrophy.
Conditions that can cause similar symptoms to muscular dystrophy include:
- spinal muscular atrophy
- congenital myopathy
- congenital myasthenic syndromes
All types of muscular dystrophy cause muscle weakness. The outlook varies widely. In some cases, the condition can be fatal within years, while in others it causes only mild symptoms late in life.
A doctor can help you figure out which type of muscular dystrophy you or your child has. They can also recommend management techniques to improve quality of life.