LGMD mechanisms of action-involved proteins are diverse. Emphasis is moving away from the identification of structural proteins and their implications in muscular dystrophies towards investigating proteins involved in muscle fiber maintenance in response to repeated injury (dysferlin, caveolin 3 and anoctamin 5), fiber remodeling under stressful conditions (calpain 3), and post-translational modifications of proteins and the enzymes involved in these processes (POMT1, POMT2, POMTGnT1). Despite the advances in modern biochemical techniques, certain proteins still exist without defined functions .
Limb-girdle muscular dystrophies (LGMD) are a group of muscular dystrophies, that until the late 1980s were identified in patients by ‘diagnosis by exclusion’. Revolutionary advances in molecular biology in the last several decades have allowed the scientific community to understand and recognize this disease more clearly. Currently, there are >25 LGMD types that have been linked to specific gene loci, and they are now estimated to constitute one third of all Duchenne muscular dystrophy cases.