Alpha-sarcoglycan-related limb-girdle muscular dystrophy R3

Alpha-sarcoglycan-related limb-girdle muscular dystrophy R3 (LGMDR3), formerly known as LGMD2D or alpha-sarcoglycanopathy, is a rare inherited muscular dystrophy caused by mutations in the SGCA gene, which encodes the alpha-sarcoglycan protein. Alpha-sarcoglycan is a critical component of the dystrophin-associated glycoprotein complex (DGC), which helps stabilize muscle cell membranes during contraction. When this protein is deficient or dysfunctional, muscle fibers become susceptible to contraction-induced damage, leading to progressive muscle degeneration. The disease primarily affects the proximal skeletal muscles, particularly those of the pelvic and shoulder girdles. Patients typically present in childhood with progressive weakness in the hips and thighs, leading to difficulty running, climbing stairs, and rising from the floor (Gowers' sign). Over time, weakness extends to the shoulder girdle muscles, making it difficult to raise the arms overhead. Calf pseudohypertrophy is commonly observed. Serum creatine kinase (CK) levels are markedly elevated, often 10 to 50 times normal values. The rate of disease progression is variable but can be severe, with many patients losing ambulation during adolescence or early adulthood. Cardiac involvement, including dilated cardiomyopathy, can occur but is less frequent than in some other sarcoglycanopathies. Respiratory function may decline as the disease progresses, particularly after loss of ambulation. There is currently no cure for LGMDR3. Management is supportive and multidisciplinary, including physical therapy to maintain mobility and prevent contractures, respiratory monitoring and support when needed, and cardiac surveillance. Corticosteroids may be considered in some cases to slow disease progression, though evidence is limited. Gene therapy approaches targeting the SGCA gene are under active investigation in clinical trials and represent a promising future therapeutic avenue.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Alpha-sarcoglycan-related limb-girdle muscular dystrophy R3