Question

Which of the following substances are expected increase in urine of Fanconi's syndrome patients, a renal disease that results from impaired ability of the proximal tubule?
A. HCO3-
B. amino acids
C. glucose
D. low molecular-weight proteins
E. All of the above

Why is the answer all of the above? Specifically, why is HCO3- included because there are no transporters in the apical side for HCO3- to enter the tubule lumen.

Answer 1

ANSWER: E. All of the above.

Reason: Fanconi syndrome is a rare kidney disorder resulting in the increased excretion of glucose, aminoacids, phosphates, bicarbonates, uric acid.

The proximal tubule is the major site for the absorption of filtered bicarbonate. In proximal renal tubular acidosis, as in case of fanconi syndrome, there is a defect in the absorption of bicarbonate ions from the filtrate thus leading to the increased excretion of bicarbonate ions in the urine. In this Fanconi syndrome type 2 bicarbonate wasting proximal renal tubular acidosis happens.