Limb-girdle muscular dystrophy type 2D (LGMD2D), also known as alpha-sarcoglycanopathy, is an inherited genetic disease in which muscles of the hip, abdomen, and shoulder progressively weaken.
Symptoms of the disease vary greatly from person to person, even among people in the same family. They can range from mild complications that do not affect lifespan to severe symptoms that are fatal by the early 20s.
People with LGMD2D commonly develop symptoms before the age of 10, although in some cases, they do not appear until adulthood. Typically the later in life symptoms appear, the less rapidly they will progress. Muscles of the hip, shoulder, and abdomen progressively weaken, although the rate at which they weaken can vary greatly. The muscles may weaken to a point where a wheelchair becomes necessary.
A minority of people with LGMD2D — about 20% — experience a weakening of the heart muscles. Involvement of the heart muscles is less common in type 2D than in other forms of limb girdle muscular dystrophy.
LGMD2D does not affect intelligence or mental function.
The cause of LGM2D is a deficiency in a protein called alpha-sarcoglycan. The function of this protein is not entirely understood. The degree of deficiency in alpha-sarcoglycan may correlate with the severity of disease symptoms.
There are numerous types of limb-girdle muscular dystrophy, and combined worldwide, they occur in approximately 5 to 70 of every 1 million people. LGMD2D is rare, but its exact incidence is unknown. It is most common in Europe, the United States, and Brazil.
There is no cure for LGMD2D and few effective treatments. Physical therapy is often recommended to retain muscle strength and mobility for as long as possible. Stretching, mechanical aids, or surgery may aid in that goal. Those who develop heart problems should consult with a cardiologist for symptomatic treatments. As muscles deteriorate, a ventilator may be required to aid breathing.
The outlook for a person with LGMD2D varies. Generally speaking, the earlier symptoms begin, the faster they progress. Some people with the disease experience only mild symptoms, and may have near-normal strength. Others with a mild course may remain able to walk for 30 years or more after symptoms appear. People with more severe symptoms can become wheelchair bound in their early teens and die in their early 20s. Death is often a result of respiratory failure.
A description of limb-girdle muscular dystrophy written in fairly scientific language.