NYU Langone doctors identify the different types of muscular dystrophy, a group of inherited muscle diseases that cause progressive weakness in the muscles that control movement. Children with muscular dystrophy are diagnosed and treated through Hassenfeld Children’s Hospital at NYU Langone.
Duchenne muscular dystrophy and Becker muscular dystrophy, the two most common types, are caused by a lack of a skeletal muscle membrane protein called dystrophin. When dystrophin is reduced or absent, the muscles break down, eventually causing problems with movements, including walking, speaking, and breathing.
There are more than 30 other types of muscular dystrophy, caused by genetic mutations. Some types of the disease are very mild and progress slowly over time as a person ages, causing symptoms that don’t greatly affect the ability to move or perform daily activities. Others types cause more rapid muscle wasting, physical disability, or shortened lifespan.
Symptoms vary based on the type of muscular dystrophy, the muscles involved, how fast the disease progresses, and the age when diagnosed.
Many types of muscular dystrophy are diagnosed in childhood, but there are several types that can appear during adolescence and adulthood.
Duchenne muscular dystrophy is the most common type of muscular dystrophy diagnosed in childhood. It first appears in very early childhood—only in boys—and progresses rapidly. Most children are unable to walk by age 12 and later need a respirator to breathe.
The disease weakens the muscles of the body, which can lead to frequent falls, difficulty walking, and wheelchair dependence. Complications of Duchenne muscular dystrophy include scoliosis, a potentially disabling curvature of the spine that can aggravate breathing difficulties, and cardiomyopathy, a deterioration of the heart muscle.
With proper medical management and support, people with Duchenne muscular dystrophy can live into adulthood.
Becker muscular dystrophy is very similar to Duchenne muscular dystrophy, but it progresses much more slowly and is less common. It affects boys and usually is diagnosed between the ages of 11 and 25.
Boys and men with Becker muscular dystrophy develop progressive weakness in the muscles of the hips, thighs, pelvis, and shoulders. The condition typically does not affect a person’s life expectancy, although Becker muscular dystrophy progresses differently in each person. Some people may require the assistance of wheelchairs in adulthood, whereas others need only a minor assistive device, like a cane, to aid in walking.
Congenital muscular dystrophies are a group of more than 30 types of muscular dystrophy affecting both boys and girls. The condition may be present at birth or appear before the age of two.
Children with congenital muscular dystrophy may develop joint problems, scoliosis, respiratory and swallowing difficulties, seizures, or vision problems. The central nervous system may also be affected, causing vision or speech problems.
The progression of these types of muscular dystrophy varies from person to person. Some children have severe intellectual impairment, whereas others reach adulthood with only minor disabilities.
Myotonic muscular dystrophy is the most common form of muscular dystrophy diagnosed in adults. It affects men and women equally.
This type of muscular dystrophy causes difficulty with muscle relaxation; weakness in the distal extremities, such as the hands and wrists; cataracts; and gastrointestinal problems, such as constipation and diarrhea. It can also lead to endocrine disturbances, such as thyroid problems and diabetes.
As myotonic muscular dystrophy progresses, it can cause an abnormal heart rhythm or weakened heartbeat. Cardiac involvement can become so severe that some people may require implantation of a pacemaker or cardiac defibrillator to regulate the heartbeat.
Limb-girdle muscular dystrophy affects the muscles of the upper arms, upper legs, shoulders, and hips. There are more than 20 forms of this type of muscular dystrophy. It can begin in people as young as age 2 and as old as age 40. It affects men and women equally.
Weakness in the upper leg muscles may cause problems with climbing stairs, rising from a seated position, walking, or running. As muscle weakness progresses, people with limb-girdle muscular dystrophy may eventually require wheelchair assistance.
Facioscapulohumeral muscular dystrophy affects the muscles of the face, shoulder blades, and upper arms. This condition usually appears before age 20 in men and women but may develop as late as age 40.
People with facioscapulohumeral muscular dystrophy first have weakness of the muscles around the eyes and mouth, shoulders, upper arms, and lower legs. Later, the abdominal and hip muscles become weak as well.
Emery–Dreifuss muscular dystrophy is a group of disorders that arise mainly in adolescent boys and young men, though young women can also be affected.
In people with this condition, muscle strength in the shoulders, upper arms, and shins may be affected. Contractures—a stiffening of the muscles near a joint—may also occur, limiting movement in the affected part of the body and causing joint deformity. A decrease in flexibility of the spine also occurs, which restricts a person’s movement.
This type of muscular dystrophy progresses slowly, and muscle weakness may not become apparent until later in life. People with Emery–Dreifuss muscular dystrophy often develop heart problems by age 30 and may need a pacemaker to keep the heart working properly.
Distal muscular dystrophy affects the muscles of the hands, feet, lower arms, and lower legs, and first appears in men and women between the ages of 40 and 60. It generally affects fewer muscles and progresses more slowly than other forms of muscular dystrophy.
This type of muscular dystrophy affects the muscles of the eyelids, face, and throat, and it can weaken vision and swallowing.
Oculopharyngeal muscular dystrophy usually appears in men and women ages 40 to 50. It is more common among people who are French-Canadian, Ashkenazi Jewish, or Hispanic.
Collagen type VI-related disorders are a spectrum of muscle disorders that can be present from infancy to adulthood. Ullrich congenital muscular dystrophy is a more severe, early onset form of the condition, whereas Bethlem myopathy tends to be diagnosed in older children and adults.
People with collagen type VI-related disorders have low muscle tone, meaning the muscles are loose or “floppy,” with overly flexible joints, contractures of the arms or legs, and decreased flexibility of the spine.
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