A 27-year-old primigravid woman was admitted with new-onset diabetes and hypertension at 32 weeks of gestation. She had worsening proximal muscle weakness, striae, and facial plethora for several months.
Physical examination showed striae over the abdomen, breasts, and dorsal and supraclavicular fat pads.
Laboratory studies were notable for a potassium of 2.9 mmol per liter (reference range, 3.5 to 5.5) and a urine protein:creatinine ratio of 24 (reference value, <30).
What is the most likely diagnosis?