Incomplete distal renal tubular acidosis in children

Aim: To describe incomplete distal renal tubular acidosis (iDRTA) in paediatric patients, a term used for the diagnosis of patients who do not develop spontaneous overt metabolic acidosis but are unable to acidify the urine in response to an ammonium chloride load.

Methods: Tests used to explore urinary acidification were revised. In addition, publications in English extracted from 161 entries yielded by a PubMed database search, using 'incomplete distal renal tubular acidosis' as keyword, were reviewed.

Results: Incomplete distal renal tubular acidosis has mostly been identified in adults with autoimmune diseases, nephrolithiasis, nephrocalcinosis and/or osteopenia. iDRTA has been reported in few paediatric patients with rickets, congenital abnormalities of kidney and urological tract and/or growth failure. The pathophysiological mechanisms potentially responsible for the defect of urinary acidification are discussed as well as the clinical and biochemical findings of iDRTA described in children.

Conclusion: The presentation of iDRTA in children differs from adults. The clinical and biochemical features of iDRTA are not well characterised in paediatric patients. The detection of iDRTA in groups of population such as heterozygous carriers of primary DRTA gene mutations and children with hypocitraturia or hypercalciuria might be of clinical interest to better know the pathophysiology and natural history of iDRTA.