A 3-year-old boy is brought to the office by his parents. They say that the child cannot keep up with his cousin, who is the same age. The boy climbs up from a squat by using his hands to push off the ground and his lower extremities. His calves appear enlarged on physical examination. This patient's condition is most likely associated with which of the following?

Question

A 3-year-old boy is brought to the office by his parents.  They say that the child cannot keep up with his cousin, who is the same age.  The boy climbs up from a squat by using his hands to push off the ground and his lower extremities.  His calves appear enlarged on physical examination.  This patient's condition is most likely associated with which of the following?

Quizplus · Accepted Answer

Eductional Objective: Duchenne muscular dystrophy is an X-linked recessive myopathy that manifests with proximal muscle weakness and enlargement of the calf muscles in boys age 2-5.  It most often results from frameshift deletions affecting the dystrophin gene.  Dystrophin provides a stabilizing interaction between the sarcolemma and the intracellular contraction apparatus, and disruption of the protein results in membrane damage and myonecrosis.

A 3-Year-Old Boy Is Brought to the Office by His