What Is Beta-Sarcoglycanopathy?
Beta-sarcoglycanopathy, also known as limb-girdle muscular dystrophy type 2E (LGMD2E), causes muscle weakness as a result of a deficiency or abnormality of beta-sarcoglycan, an important protein in muscle. The condition is caused by mutations in the SGCB gene. The symptoms of beta-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 beta-sarcoglycanopathy is a progressive weakening of the muscles in the hips, shoulders, and abdomen (the proximal muscles). It may also affect the muscles in the thigh and in the upper arm. The rate at which the muscles weaken can vary, but many experience severe progressive weakness that a wheelchair becomes necessary. Other symptoms of the condition include enlarged calf muscles (calf hypertrophy), contractures, scapular winging (prominence of the shoulder blades), and scoliosis. Respiratory and/or heart complications are also possible for individuals with beta-sarcoglycanopathy and may be a cause of early death. Beta-sarcoglycanopathy does not affect intelligence or cognitive function.
How Common Is Beta-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 beta-sarcoglycanopathy is unknown.
How Is Beta-Sarcoglycanopathy Treated?
There is no cure for beta-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 Beta-Sarcoglycanopathy?
The outlook for an individual with beta-sarcoglycanopathy varies. Generally speaking, the earlier the symptoms begin, the faster they progress. However, because symptoms and onset can be variable, the prognosis can also be variable. Individuals with more severe symptoms often become wheelchair-bound in their early teens and die in early adulthood, with death usually being due to respiratory and/or cardiac complications. The lifespan in individuals with mild symptoms may not be significantly affected.