Background dRTA is a tubulopathy characterized by metabolic acidosis with normal anion gap secondary to a defective secretion of H+ ions by the collecting tubule. This anomaly leads to an inability to acidify the urine during systemic acidemia. There are more than 50 different mutations, with an autosomal recessive or dominant pattern of transmission. Clinical features usually appear from two years of age as vomiting, dehydration and failure to thrive, although the first signs may be present from the first weeks of life. In recessive forms can be associated with sensorineural deafness. The prognosis is favorable if alkali replacement is performed properly. However, urolithiasis, nephrocalcinosis and chronic renal failure may appear if the diagnosis is delayed or the treatment is inadequate.
Case Report We report a 4-year-old Morrocan girl with a history from the first months of life characterized by failure-to-thrive, hyporexia, polydipsia and polyuria, and delayed motor function. In recent months she was unable to ambulate due to progressive muscle weakness, especially of the lower limbs. Physical findings included a severe weight and height delay, signs of severe malnutrition and rickets, and tachypnea. Laboratory findings were consistent with distal renal tubular acidosis (metabolic acidosis with normal anion gap, severe hypokaliemia, hypophosphatemia, mild hypocalcemia, and hypouricemia, with urinary pH > 6 and positive urinary gap). Also, bilateral renal nephrocalcinosis was found. Alkali replacement was able to correct the electrolytic abnormalities and promote catch-up.
Comments dRTA must be suspected in the presence of the clinical and laboratory findinds reported.