What Is Alpha-Sarcoglycanopathy?
Alpha-sarcoglycanopathy, also known as limb-girdle muscular dystrophy type 2D (LGMD2D), causes muscle weakness as a result of a deficiency or abnormality of alpha-sarcoglycan, an important protein in muscle. The condition is caused by mutations in the SGCA gene. The symptoms of alpha-sarcoglycanopathy can vary greatly from person to person, even within the same family. Some individuals with the disease may experience only mild muscle weakness, while others may have severe symptoms that can be fatal. The age at which symptoms first develop is also variable, although the condition typically presents in childhood.
The most common symptom of alpha-sarcoglycanopathy is a progressive weakening of muscles in the hips, shoulders, and abdomen (the proximal muscles). The rate at which the muscles weaken can vary, but many experience progressive weakness to a point where a wheelchair becomes necessary. Other symptoms individuals may experience include enlarged calf muscles (calf hypertrophy), contractures, scapular winging (prominence of the shoulder blades), and scoliosis. Respiratory and/or heart complications are also possible, although involvement of the heart muscles is less common in alpha-sarcoglycanophathy compared to other types of limb-girdle muscular dystrophy. Alpha-sarcoglycanopathy does not affect intelligence or cognitive function.
How Common Is Alpha-Sarcoglycanopathy?
There are numerous types of limb-girdle muscular dystrophy. The estimated prevalence of all types of limb-girdle muscular dystrophy is 1 in 15,000 individuals. The exact proportion of cases that have alpha-sarcoglycanopathy is unknown. However, it is reported to be most common in Europe, the United States, and Brazil.
How Is Alpha-Sarcoglycanopathy Treated?
There is no cure for alpha-sarcoglycanopathy and there are 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 also aid in that goal. As muscles deteriorate, a ventilator may be required to help with breathing. Cardiac surveillance is recommended, and those who develop heart problems should consult with a cardiologist for appropriate treatment.
What Is the Prognosis for an Individual with Alpha-Sarcoglycanopathy?
The outlook for an individual with alpha-sarcoglycanopathy varies. Generally speaking, the earlier the symptoms begin, the faster they progress. However, because symptoms and onset can be variable, the prognosis can be variable. Individuals with more severe symptoms often become wheelchair-bound in their early teens and die in early adulthood, with death often the result of respiratory failure. Individuals with mild symptoms may remain able to walk for 30 or more years after symptoms appear and may have a normal lifespan.