A 27-year-old man presented with weight loss, diarrhea, tremor, and proximal muscle weakness. The blood level of potassium was 1.8 mmol per liter. A diagnosis was made.

Gene therapy has helped a 9-year-old boy regain enough muscle strength to run. If successful in others, the treatment could change the lives of thousands of children with Duchenne muscular dystrophy.

A 42-year-old man said testosterone therapy helped him build muscle and restore mood and energy. But as a former fitness model, he said it didn't measure up to his former peak physique.