Ans. A. Duchenne Muscular hypertrophyDuchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy. The symptom of muscle weakness usually begins around the age of four in boys and worsens quickly. Females with a single copy of the defective gene may show mild symptoms. The disorder is X-linked recessive. Early features include a gait abnormality, which classically is a waddling, wide-based gait with hyper lordosis of the lumbar spine and toe walking. The Gower sign is a classic physical examination finding in MD and results from weakness in the child's proximal hip muscles. The second important phase in Duchenne MD is the loss of ambulation. This usually occurs between the ages of 7 and 13 years, with some patients becoming wheelchair-bound by age 6 years. Duchenne MD is a terminal disease in which death usually occurs by the third decade of life (mostly from cardiopulmonary compromise). Other clinical findings in Duchenne MD include absent deep tendon reflexes in the upper extremities and patella (though the Tendo Achillis reflex remains intact even in the later stages of this disease), pain in the calves with activity (<30% of patients), pseudohypertrophy of the calf (60%), and macroglossia (30%).