<prompt> Causes of Type 2 renal tubular acidosis are all except:CystinosisLowe syndromeEssential fructosuriaGaiatosemia  <response>: Ref: Nelsons Textbook of Pediatrics 18th edition: page no.2197Explanation:Renal tubular acidosis RTAIt is a disease state characterized by a normal anion gap metabolic acidosis resulting from either impaired bicarbonate reabsorption or impaired urinary acid hydrogen ion excretion.There are 3 main forms of RTA:Proximal type II RTADistal type I RTA. andHyperkalemic type IV RTA.Mixed lesions those with elements of type I and II RTA, which occur primarily in patients with inherited carbonic anhydrase deficiency, are designated as type III RTA by some authors. Causes of HvponatremiaHYPOVOLEMICHYPONATREMIAEUVOLEMC HYPONATREMIAHYPERVOLEMICHYPONATREMIAExtrarenal losses Gastrointestinal emesis, darrhea Skin sweating or bums Third space losses SIADH Glucocorticoid deficiency Hypothyroidism Water intoxication CHF Orthosis Nephrotic syndrome Renal failure Capillary leak due to sepsis Hypoaibuminemia due to gastrointestinal disease protein-losing enteropathyRenal losses Thiazide or loop diuretics Juvenile nepbronophthisis Tubulointerstitial nephritis Obstructive uropathy Cerebral salt wasting Proximal type II renal tubular acidosis Lack of aldosterone effect high serum potassiumProximal RTA usually occurs as a component of global proximal tubular dysfunction or Fanconi syndrome, which is characterized by low molecular weight proteinuria, glycosuria, phosphaturia, aminoaciduria, and proximal RTA See the following table 