Question:medium
Impaired function of aquaporins (water channels) results in which of the following conditions?
Impaired function of aquaporins (water channels) results in which of the following conditions?
Show Hint
If the ADH-driven water channel fails, the kidney cannot concentrate urine.
Updated On: Jun 23, 2026
- Liddle syndrome
- Nephrogenic diabetes insipidus
- Cystic fibrosis
- Bartter syndrome
Show Solution
The Correct Option is B
Solution and Explanation
Channel-to-disease matching angle: each option is a channelopathy, so pair the channel with its disease.
Aquaporins are water channels. The renal star is aquaporin-2 in the collecting duct, which ADH (vasopressin) shuttles to the apical membrane so water can be reabsorbed and urine concentrated. Break that channel (or its V2 receptor) and water cannot follow the osmotic gradient even with plenty of ADH around. The patient pours out large volumes of dilute urine: that is nephrogenic diabetes insipidus, the renal-resistance form of DI.
Now match the distractors to their own channels. Liddle syndrome is an overactive ENaC sodium channel causing low-renin hypertension. Cystic fibrosis is a faulty CFTR chloride channel. Bartter syndrome is loss of the NKCC2 cotransporter in the loop of Henle. None of these are water channels.
So impaired aquaporin function maps cleanly to nephrogenic diabetes insipidus.
Ref: Guyton and Hall Textbook of Medical Physiology, 13e.
Aquaporins are water channels. The renal star is aquaporin-2 in the collecting duct, which ADH (vasopressin) shuttles to the apical membrane so water can be reabsorbed and urine concentrated. Break that channel (or its V2 receptor) and water cannot follow the osmotic gradient even with plenty of ADH around. The patient pours out large volumes of dilute urine: that is nephrogenic diabetes insipidus, the renal-resistance form of DI.
Now match the distractors to their own channels. Liddle syndrome is an overactive ENaC sodium channel causing low-renin hypertension. Cystic fibrosis is a faulty CFTR chloride channel. Bartter syndrome is loss of the NKCC2 cotransporter in the loop of Henle. None of these are water channels.
So impaired aquaporin function maps cleanly to nephrogenic diabetes insipidus.
Ref: Guyton and Hall Textbook of Medical Physiology, 13e.
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