Abstract: Objective To investigate the clinical characteristics and gene diagnosis of primary distal renal tubular acidosis (dRTA) in children. Methods The clinical data and genetic test results of 21 patients with primary dRTA were retrospectively analyzed. Results Among the 21 children, there were 12 boys and 9 girls. The median onset age was 9 (2~24) months and the median diagnosis age was 31 (24~54) months. The main clinical features were growth retardation, polyuria, feeding difficulties, fatigue and repeated urinary tract infection. All the children had medullary calcareous deposition, and 9 cases (42.8%) had renal cystic disease, including 3 cases with medullary sponge kidney. There were 12 cases of proteinuria, including 8 cases of renal tubular proteinuria, 3 cases of mixed proteinuria and 1 case of glomerular proteinuria. After acidosis was corrected, only one case of glomerular proteinuria persisted, and the rest returned to normal. All children were given sodium citrate and potassium citrate solution orally. The median follow-up time was 45 (28 ~ 61) months. By the time of the last follow-up, all the children's metabolic disorders were corrected and 1 child developed stage 2 chronic renal insufficiency. Total exon sequencing was performed in 10 children, gene variation was detected in 6 children, and no clinical report was found in case 4, 5 and 6. Case 4 was a compound heterozygous mutation of ATP 6 V 1 B 1 c. 687 G> A, c. 1397 C>A (p.P 229 G, p.S 466 X); Case 5 was a compound heterozygous mutation of ATP6V1B1 c.232G >A, c.1354 del (p.G78R, p.F452fs), and case 6 was a compound heterozygous mutation of ATP6V0A4 c.1376C>T, c.1029 + 5G>A (p.S459P). Conclusion In this study, three new compound heterozygous mutations were found, which extended the gene mutation spectrum. Genetic testing is helpful for diagnosis and genetic counseling.

Key words: primary distal renal tubular acidosis; clinical characteristic; gene