Muscular dystrophies are a group of diseases that are passed down genetically. These diseases cause damage and weakness to muscles over time. This damage and weakness is caused by the lack of a protein called dystrophin, which is necessary for normal muscle function. The absence of this protein can cause problems with walking, swallowing, and muscle coordination.
There are more than 30 different kinds of muscular dystrophies, which vary in symptoms and severity.
Muscular dystrophy can occur at any age, but is usually diagnosed in childhood. Young boys are more likely to have this disease than girls.
The prognosis for muscular dystrophy depends on the type and the severity of symptoms. However, most individuals with muscular dystrophy do lose the ability to walk and eventually require a wheelchair. There is no known cure for muscular dystrophies, but certain treatments may help.
There are over 30 different types of muscular dystrophy, which are divided into nine different categories used for diagnosis.
This type of muscular dystrophy is the most common among children. The majority of individuals affected are boys; it is rare for girls to develop Duchenne. Symptoms include:
- trouble walking
- loss of reflexes
- difficulty standing up
- poor posture
- bone thinning
- scoliosis, which is excessive curvature of the spine
- mild mental impairment
- breathing difficulties
- swallowing problems
- lung and heart weakness
Individuals with Duchenne typically require a wheelchair before their teenage years. The life expectancy for those with this disease is late teens or twenties.
Becker muscular dystrophy is similar to Duchenne muscular dystrophy, but less severe. This type of muscular dystrophy also more commonly affects boys. Muscle weakness occurs mostly in the arms and legs, with symptoms appearing between age 11 and 25. Other symptoms of Becker muscular dystrophy include:
- walking on the toes
- frequent falls
- muscle cramps
- trouble getting up from the floor
Many with this disease do not need a wheelchair until they are in their mid-thirties or older, while a small percentage never require one. Most individuals live until middle age or later.
Congenital muscular dystrophies are often discovered between birth and age 2. This is when parents begin to notice that their child’s motor functions and muscle control are not developing as they should. Symptoms vary and may include:
- muscle weakness
- poor motor control
- being unable to sit or stand without support
- foot deformities
- trouble swallowing
- respiratory problems
- vision problems
- speech problems
- intellectual impairment
While symptoms vary from mild to severe, the majority of those with congenital muscular dystrophy are unable to sit or stand without help. The lifespan of someone with this type also varies, depending on the symptoms. Some individuals die in infancy while others live until adulthood.
This form of muscular dystrophy, also called Steinert’s disease or dystrophia myotonica, causes an inability to relax muscles after they contract (myotonia). Myotonia is only found in this type of muscular dystrophy.
Myotonic dystrophy can affect the muscles in the face as well as the central nervous system, adrenal glands, heart, thyroid, eyes, and gastrointestinal (GI) tract. Symptoms most often appear first in the face and neck. Symptoms include:
- drooping muscles of the face, producing a thin, haggard look
- difficulty lifting the neck (weak neck muscles)
- difficulty swallowing
- droopy eyelids (ptosis)
- early baldness in front area of the scalp
- poor vision, including cataracts
- weight loss
- increased sweating
This dystrophy type may also cause impotence and testicular atrophy in males; in women, it may cause irregular periods and infertility.
Mytonic dystrophy is typically diagnosed in adults in their twenties or thirties. While symptoms can affect quality of life, most are not life threatening, and sufferers often live a long life.
FSHD is also known as Landouzy-Dejerine disease. This type of muscular dystrophy affects the muscles in the face, shoulders, and upper arms. Individuals with FSHD may have difficulty chewing or swallowing; their mouths may take on a crooked appearance. Shoulders look slanted, and the shoulder blades appear wing like. A smaller number of individuals may develop hearing and respiratory problems.
FSHD tends to progress slowly; symptoms usually appear during an individual’s teenage years, but may lie dormant until his or her forties. Most individuals with this condition live a full lifespan.
Limb-girdle muscular dystrophy causes weakening of the muscles and loss of muscle bulk. This type of muscular dystrophy usually begins in the shoulders and hips, and may also occur in the legs and neck. Individuals with limb-girdle muscular dystrophy may find it hard to get up out of a chair, walk up and down stairs, and carry heavy items. They may also stumble and fall more easily.
Limb-girdle muscular dystrophy affects both males and females. Most people with this form of muscular dystrophy are disabled by age 20; however, most individuals have a normal life expectancy.
OPMD causes weakness in the facial, neck, and shoulder muscles. Other symptoms include:
- drooping eyelids
- trouble swallowing
- voice changes
- vision problems
- heart problems
- difficulty walking
OPMD occurs in both men and women and is usually diagnosed when individuals are in their forties or fifties.
This type, also called Distal myopathy, affects the muscles in the forearms, hands, calves, and feet. It may also affect the respiratory system and heart muscles. Symptoms, which include the loss of fine motor skills and difficulty walking, tend to progress slowly. Most individuals, both male and female, are diagnosed between 40 and 60 years of age.
Emery-Dreifuss muscular dystrophy tends to affect more boys than girls. This type of muscular dystrophy usually begins in childhood. Symptoms include:
- weakness in upper arm and lower leg muscles
- breathing problems
- heart problems
- shortening of the muscles in the spine, neck, ankles, knees, and elbows
Most individuals with Emery-Dreifuss muscular dystrophy die in mid-adulthood from heart or lung failure.
There are a number of different tests used to diagnose muscular dystrophies. These tests include:
- enzyme tests—blood is tested for enzymes released by damaged muscles
- genetic testing—blood is tested for genetic markers for muscular dystrophy
- electromyography—an electrode needle is inserted into a muscle to test the muscle’s electrical activity
- muscle biopsy—a sample of the muscle is tested for muscular dystrophy
There is currently no cure for muscular dystrophy, but treatments can help to manage symptoms and slow the progression of the disease. Treatments depend on the symptoms experienced.
Treatment options include:
- corticosteroid drugs, which help strengthen muscles and slow the progression of muscle deterioration
- physical therapy, which helps to strengthen muscles and maintain their range of motion
- occupational therapy, which helps the individual to become more independent. This therapy addresses coping skills, social skills, and how to access helpful community services.
- assisted ventilation
- medication for heart problems
- surgery to help correct shortening of muscles, treat scoliosis, repair cataracts, or treat cardiac problems