This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'Duchenne Muscular Dystrophy is a disease of- \nSelect and explain. \nA. Neuromuscularj unction, B. Sarcolemmal proteins, C. Muscle contractile proteins, D. Disuse atrophy due to muscle weakness', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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 Gower's 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.", 'role': 'assistant'}]