<prompt> Defect seen in Bartter syndrome isDistal Convoluted TubuleProximal Convoluted TubuleThin descending limb of loop of HenleThick ascending limb of loop of Henle  <response>: D Thick ascending limb of loop of Henle?Bartter Syndrome:-An inborn autosomal recessive defect, in the Na-K-2C- cotransporter in the thick ascending limb of the loop of Henle, leading to NaCl and water wasting.-Symptoms are polyuria, polydipsia, episodes of dehydration, faltering growth and constipation.-There may be maternal polyhydramnios with an affected fetus.-The resultant ECF volume contraction causes secondary renin secretion and raised aldosterone levels, with avid Na and water reabsorption in the distal tubule and reciprocal K and H secretion into the urine.-The blood pressure is normal; the hyperreninaemia is a compensatory response to maintain normal blood pressure in the presence of chronic ECF volume depletion.-There is also increased renal prostaglandin E2 production.?Fanconi Syndrome:oDiffuse proximal tubular dysfunction, leading to excess urinary loss of:-Glucose - glycosuria with normal blood glucose-Phosphate - hypophos- phataemia, rickets-Amino acids - no obvious clinical consequence-HCO3- - leading to proximal RTA-K - causing hypokalae- mia-NaCl- water - leading to polyuria polydipsia, chronic ECF volume depletion, faltering growth.-Tubular proteinuria - loss of low molecular weight proteins including retinol binding protein. 