<prompt> Duchenne Muscular Dystrophy is a disease ofNeuromuscular junctionSarcolemmal proteinsMuscle contractile proteinsDisuse atrophy due to muscle weakness  <response>: DUCHENNE MUSCULAR DYSTROPHY PSEUDO HYPERTROPHIC MUSCULAR DYSTROPHYDuchenne muscular dystrophy is the most common hereditary neuromuscular disease affecting all races and ethnic groups.Inheritance: X linked recessivePresentation occurs between ages 3 and 5 PathogenesisDuchenne muscular dystrophy is caused by a mutation in the gene responsible for producing dystrophin.Dystrophin is subsarcolemmal protein localized to the inner surface of the sarcolemma of the muscle fibre.Dystrophin is part of Dystrophin - Glycoprotein sarcolenzmal complex and this protein deficiency leads to secondary loss of sarcoglycans and dystroglycans resulting in weakness of sarcolemma, causing membrane tears and muscle fibre necrosis.Clinical manifestations:Gowers sign is positivePseudohypertrophy of the calf is seen muscle is replaced by fat connective tissueLoss of muscle strength is progressive.Proximal muscles and neck flexors are involved moreLeg involvement is more severe than arm involvement.Contractures of heel cords and iliotibial band occurs by age of 6 yearsprogressive scoliosis develops.Complications:Chest deformity scoliosis: Impairs pulmonary function By age of 16 and 18 years patients are predisposed to serious pulmonary fatal infections.Cardiac: Cardiomyopathy and CHF may be seen Cardiac cause of death is uncommonIntellectual impairment: is common IQ is one SD below the mean 