Limb-girdle muscular dystrophies

Abstract

The limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of hereditary neuromuscular disorders with predominant or selective weakness in proximal limb and axial muscles, having an estimated incidence of 1:100,000. While they are congenital in nature, most of them manifest in adulthood with a range of presentation from early childhood to late adulthood, even into 70s and 80s. LGMD has onset of weakness of pelvic and shoulder girdle muscles although specific disorders may initially manifest more prominently in the pelvic or the shoulder girdle. During the progressive course, weakness may spread outside of the pelvic and the shoulder girdle. Depending on the type of LGMD, the lungs and heart may be involved. Creatine kinase (CK) levels may be normal, mildly elevated, or highly elevated. Usually extraocular muscles are spared. Cranial muscles are spared as well, except, in some special cases, facial muscles may be involved. A large number of LGMDs have been described-both clinically and molecularly.