<prompt> An 8 years old child suffering from recurrent attacks of polyuria since childhood presents to the pediatrics OPD. On examination, the child has short stature. Vitals and B.P. are normal. S. Creatinine - 6 mgdL, HCO3 - 16 meqL, S Na - 134 meqL. On USG, bilateral small kidneys are seen. Diagnosis is:Reflux nephropathyNephronophthisisPolycystic kidney diseaseMedullary cystic kidney disease  <response>: b. NephronophthisisRef: Nelsons 20e p 2537In this case bilateral small kidneys with clinical features of renal failure polyuria are suggestive of Nephronophthisis. 