Abstract
Primary distal renal tubular acidosis (dRTA) or Type 1 RTA in children is caused by
a genetic defect (involved genes ATP6V0A4, ATP6V1B1, SLC4A1, FOXI1, or WDR72), which causes tubular transport defects characterized by an inability to appropriately
acidify urine with resultant persistent hyperchloremic metabolic acidosis. Retrospective
analysis of 28 children (14 males) under the age of 14 years with dRTA seen from 2010
to 2019 was reviewed, and detailed clinic records were analyzed. The clinical features,
investigations, and response to treatment were recorded. The median age of the children
at presentation was 30 months (range: 9.25–72 months), and the median age at onset
of symptoms was 2 months. All the children had growth failure, polyuria, and polydipsia
at presentation. Mean serum potassium, pH, bicarbonate, and anion gap at presentation
was 2.3 ± 0.5 mmol/L, 7.22 ± 0.09, 13.28 ± 4.37 mmol/L, and 9.3 ± 2.18, respectively.
Mean serum potassium, pH, bicarbonate at follow-up was 3.88 ± 0.6 mmol/L, 7.35 ± 0.06,
and 20.13 ± 4.17 mmol/L, respectively. The median z-score for the weight for age and
height for age at initial presentation was −4.77 (–7.68 to –3.74) and –4.21 (–5.42
to –2.37) and at follow-up was –3.35 (–5.29 to –1.55) and –3.84 (–5.36 to –1.63),
respectively. Twenty-two (78.6%) children had medullary nephrocalcinosis. Four children
had sensorineural hearing loss. Seven children had genetic testing done, and six had
pathogenic or likely pathogenic variants in ATP6V1B1 and ATP6V0A4 gene. Children with dRTA have a guarded prognosis and ATP6V1B1 and ATP6V0A4 mutations are the most common implicated genetic defect in Indian children with distal
RTA.
Keywords
distal renal tubular acidosis - genetic testing - hypokalemia - metabolic acidosis
- nephrocalcinosis
