In polycystic kidney disease, when do cysts typically form and when do about half develop CKD?

• A. Cysts form by age 50; CKD by 30
• B. Cysts form by age 20; CKD by 40
• C. Cysts form by age 40; CKD by 60
• D. Cysts form by age 30; about half develop CKD by age 50

Answer: (D)

Polycystic kidney disease progresses over decades with cysts developing well before symptoms and kidney function gradually declining as those cysts grow. In the common autosomal dominant form, cysts are typically detectable by adulthood, often by around age 30. The disease then advances slowly, with the cumulative loss of healthy nephrons leading to chronic kidney disease for many by midlife. That means about half of affected individuals have CKD by roughly age 50. This timeline reflects the usual natural history of cyst formation early and progressive function decline over decades, which is why the statement about cysts forming by 30 and about half reaching CKD by 50 is the best fit. Other options imply cysts appear later or CKD develops much earlier, which conflicts with the typical gradual progression seen in PKD.