pediatrics
Limb Girdle Dystrophy
Introduction
Limb-girdle dystrophy is a muscular dystrophy that has numerous subtypes; some are autosomal recessive and some are autosomal dominant. Time of onset is determined by the mode of inheritance, but the disease often begins in childhood. Symptoms are slowly progressive, impacting the proximal muscles. Diagnosis is by DNA analysis and muscle biopsy. Treatment is focused on maintenance of function and prevention of contractures. Muscular dystrophies are inherited, progressive muscle disorders resulting from defects in one or more genes needed for normal muscle structure and function; dystrophic changes (eg, muscle fiber necrosis and regeneration) are seen on biopsy specimens. As a group, limb-girdle dystrophies are the fourth most common inherited muscle disease. The overall prevalence varies depending on the specific subtype and population studied, with estimates ranging from 2 to 10/100,000 ( References ). Males and females are affected equally. Insights from molecular biology have redefined the way these disorders are classified, and the nomenclature is in transition ( References ). Autosomal dominant forms were classified as limb-girdle muscular dystrophy (LGMD) 1A, -1B, -1C, and so on, and recessive forms were classified as LGMD 2A, -2B, -2C, and so on. However, after the letter Z was used in 2016 to name a recessive form of LGMD, no letters were left to name the next form to be discovered. Henceforth, the nomenclature would begin with the letter D for dominant and R for recessive, followed by a number, indicating the order in which the locus was delineated, followed by the protein product of the disorder. For example, the previously termed LGMD1F is now LGMD D2 transportin 3. Limb-girdle dystrophy, under the new nomenclature, has 29 known subtypes, 24 Autosomal Dominant and 5 