Muscular Dystrophy – KidsHealth – the Web’s most visited …

The different types of muscular dystrophy affect different sets of muscles and cause different degrees of muscle weakness.

Duchenne muscular dystrophy is the most common and the most severe form of MD. It affects about 1 out of every 3,500 boys. (Girls can carry the gene that causes the disease, but they usually have no symptoms.) This form occurs because of a problem with the gene that makes dystrophin. Without this protein, the muscles break down and a child becomes weaker.

Children with Duchenne MD usually begin to have problems around age 5, as the pelvic muscles begin to weaken. Most kids with this form need to use a wheelchair by age 12. Over time, their muscles weaken in the shoulders, back, arms, and legs.

Eventually, the respiratory (breathing) muscles and heart muscle also may weaken in the teenage years, requiring further treatments. Although most kids with Duchenne MD have average intelligence, about a third experience learning disabilities and a small number are intellectually disabled.

Advances in medical care are helping kids with Duchenne to live longer and healthier lives.

While the incidence of Duchenne is known, it's unclear how common other forms of MD are because the symptoms can vary so widely between individuals. In fact, in some people the symptoms are so mild that the disease goes undiagnosed.

Becker muscular dystrophy is similar to Duchenne, but is less common and progresses more slowly. This form of MD, which affects about 1 in 30,000 boys, is caused by insufficient production of dystrophin, too.

Symptoms begin during the teen years, then follow a pattern similar to Duchenne MD. Muscle weakness first begins in the pelvic muscles, then moves into the shoulders and back. Many children with Becker MD have a normal life span and can lead long, active lives without the use of a wheelchair.

Myotonic dystrophy, also known as Steinert's disease, is the most common adult form of MD, although half of all cases are diagnosed in people under 20 years old. It is caused by a portion of a particular gene that is larger than it should be. The symptoms can appear at any time during a child's life.

The main symptoms include muscle weakness, myotonia (in which the muscles have trouble relaxing once they contract), and muscle wasting (when the muscles shrink over time). Kids with myotonic dystrophy also can have cataracts and heart problems.

Limb-girdle muscular dystrophy affects boys and girls equally. Symptoms usually start when kids are between 8 and 15 years old. This form progresses slowly, affecting the pelvic, shoulder, and back muscles. The severity of muscle weakness varies some kids have only mild weakness while others develop severe disabilities and as adults need to use a wheelchair.

Facioscapulohumeral muscular dystrophy can affect both boys and girls, and the symptoms usually first appear during the teen years. It tends to progress slowly. Muscle weakness first develops in the face, making it difficult for a child to close the eyes, whistle, or puff out the cheeks. The shoulder and back muscles gradually become weak, and kids have trouble lifting objects or raising their hands overhead. Over time, the legs and pelvic muscles also may lose strength.

Other types of MD, which are rare, include distal, ocular, oculopharyngeal, and Emery-Dreifuss.

Read the original post:
Muscular Dystrophy - KidsHealth - the Web's most visited ...