What is Gamma-Sarcoglycanopathy?
Gamma-sarcoglycanopathy, also known as limb-girdle muscular dystrophy type 2C (LGMD2C), represents a spectrum of disorders that typically cause muscle weakness as a result of a deficiency of the gamma-sarcoglycan protein in the dystrophin-glycoprotein complex, a component of the muscle system. Symptoms of the disease vary greatly from person to person, even among people in the same family. Some people with the disease can have a mild course where they are nearly asymptomatic, while others may have severe symptoms that can be fatal.
People with limb-girdle muscular dystrophy type 2C (LGMD2C) develop symptoms at variable ages, though symptoms tend to first present in childhood. LGMD2C does not affect intelligence or mental function; the primary symptom is progressive muscle weakness of the hip, shoulder, and abdomen (proximal muscles). The rate at which the muscles weaken can vary, but many experience progressive weakness to a point where a wheelchair becomes necessary, often in adolescence, although in individuals with later onset, a wheelchair may not be needed until adulthood. Other possible features include enlarged calf muscles, contractures, winging of the shoulder blade, scoliosis, and mild heart complications, such as heart rhythm abnormalities and cardiomyopathy, which can lead to heart failure. Respiratory complications are also associated with the sarcoglycanopathies, and may be a cause of death.
There have also been reports of just muscle pain with exercise, proximal muscle weakness (muscles that are close to the center of the body are weak), or hyperCKemia (elevated creatine kinase levels with no known symptoms). These may not be distinct forms of the condition and represent the variable nature of the condition.
How common is Gamma-Sarcoglycanopathy?
There are numerous types of limb-girdle muscular dystrophy. Autosomal recessive LGMD has an estimated prevalence of 1 in 15,000 individuals. The percentage of LGMD cases attributed to LGMD2C is unknown, but it may be more common in certain populations, such as North Africans and Gypsies.
How is Gamma-Sarcoglycanopathy treated?
There is no cure for gamma-sarcoglycanopathy 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. As muscles deteriorate, a ventilator may be required to aid breathing. Cardiac surveillance is recommended, and those who develop heart problems should consult with a cardiologist for symptomatic treatments.
What is the prognosis for a person with Gamma-Sarcoglycanopathy?
The outlook for a person with LGMD2C varies. LGMD2C is considered one of the more severe forms of autosomal recessive LGMD. Generally speaking, the earlier symptoms begin, the faster they progress. However, because symptoms and onset can be variable, prognosis can be variable. People with more severe symptoms can become wheelchair bound in their early teens and die in early adulthood, typically from respiratory complications.