All the following phosphorus binders are used in chronic renal insufficiency EXCEPT

Correct Answer: D

Rationale: Aluminum binders are avoided in chronic renal insufficiency due to toxicity; others are standard treatments.

Correct Answer: B

Rationale: Gowers sign, a classic indicator of proximal muscle weakness seen in Duchenne muscular dystrophy, typically becomes fully evident by age 5 as the child struggles to rise from the floor.

Correct Answer: D

Rationale: Hypoparathyroidism does not typically cause myopathy; the others can, via mechanisms like steroid-induced muscle breakdown or thyroid hormone effects on muscle metabolism.

Correct Answer: C

Rationale: Lower limb weakness is not a core feature of MFS, which focuses on ophthalmoplegia, ataxia, and areflexia.

Correct Answer: A

Rationale: Fatigue, particularly worsening with activity and improving with rest, is the most characteristic feature of myasthenia gravis.