<prompt> Duchenne Muscular Dystrophy is a disease of-Neuromuscularj unctionSarcolemmal proteinsMuscle contractile proteinsDisuse atrophy due to muscle weakness  <response>: Ans. is b i.e., Sarcolemmal protein DUCHENNE MUSCULAR DYSTROPHY : PSEUDOHYPEROPHIC MUSCULAR DYSTROPHY o Duchenne muscular dystrophy is the most common hereditary neuromuscular disease affecting all races and ethnic groups. o Inheritance : X linked recessive o Presentation occurs between ages 3 and 5 Pathogenesis o Duchenne muscular dystrophy is caused by a mutation in the gene responsible for producing dystrophin. o Dystrophin is subsarcolemmal protein localized to the inner surface of the sarcolemma of the muscle fibre. o Dystrophin is pa of Dystrophin - Glycoprotein sarcolemmal complex and this protein deficiency leads to secondary loss of sarcoglycans and dystroglycans resulting in weakness of sarcolemma, causing membrane tears and muscle fiber necrosis. Clinical manifestations: o Gowers sign is positive o Pseudohyperophy of calf is seen muscle is replaced by fat connective tissue o Loss of muscle strength is progressive. o Proximal muscles and neck flexors are involved more o Leg involvement is more severe than arm involvement. o Contractures of heel cords and iliotibial band occurs by age of 6 years o progressive scoliosis develops. 