ESPN 53rd Annual Meeting

ESPN 2021


 
LONG-TERM OUTCOME OF A SERIES OF PATIENTS WITH PRIMARY DISTAL RENAL TUBULAR ACIDOSIS
Leire Madariaga 4 Sara Gomez-Conde 1 Alejandro Garcia-Castano 1 Mireia Aguirre 3 Maria Herrero 3 Leire Gondra 4 Ana Vinuesa 3 Nelida Garcia-Perez 2 Gema Ariceta 5 Luis CastaƱo 4

1- IIS BIOCRUCES BIZKAIA
2- PEDIATRIC NEPHROLOGY DEPARTMENT, BASURTO UNIVERSITY HOSPITAL, IIS BIOCRUCES BIZKAIA, UNIVERSITY OF THE BASQUE COUNTRY
3- PEDIATRIC NEPHROLOGY DEPARTMENT, CRUCES UNIVERSITY HOSPITAL, IIS BIOCRUCES BIZKAIA
4- PEDIATRIC NEPHROLOGY DEPARTMENT, CRUCES UNIVERSITY HOSPITAL, IIS BIOCRUCES BIZKAIA, UNIVERSITY OF THE BASQUE COUNTRY
5- PEDIATRIC NEPHROLOGY DEPARTMENT, VALL DE HEBRON UNIVERSITY HOSPITAL, UNIVERSIDAD AUTONOMA DE BARCELONA
 
Introduction:

Primary Distal renal tubular acidosis (dRTA) is a rare genetic disorder caused by mutations in ATP6V0A4, ATP6V1B1 and SLC4A1 genes, which encode transporters that regulate acid-base balance in the collecting duct.

Material and methods:

This is a retrospective study on the molecular and clinical data from diagnosis and long-term follow-up of 16 patients with primary dRTA.

Results:

 Molecular analyses revealed that 9 patients had mutations in ATP6V0A4, 5 in ATP6V1B1 and 2 in SLC4A1. We found a novel intragenic deletion in the ATP6V0A4. We reported a common ATP6V0A4 gene variant (c.1691+2dupT) in two thirds of these patients, suggesting a founder effect. The mean age at last follow-up was 26.6 (SD 15) years. Median SDS height was -1.17 (IQR -1.71; -0.3), and it did not change significantly from diagnosis (-1.02, IQR -1.79; -0.14, P=0.28).  Final SDS height was significantly correlated with the age at diagnosis (P=0.03). Patients with an adequate metabolic control (plasma bicarbonate > 22 mEq/L and urinary calcium < 0.2 mg/mg of creatinine) had a significantly better SDS height at last follow-up (P=0.02). Six out of 16 patients (37.5%) had a chronic kidney disease (CKD) at last follow-up, with a mean GFR of 48.9 (SD 29.1) ml/min/1.73m2. The mean age of patients with CKD was 37.5 (SD 9.3) years. The development of CKD was not significantly associated with the age at diagnosis or with an adequate metabolic control at last follow-up. The incidence of sensorineural hearing loss (SNHL) was very high in ATP6V1B1 patients, though not universal. Patients harboring ATP6V0A4 mutations also developed SNHL at a high rate (80%) over time. All except one patient developed nephrocalcinosis or lithiases over time.

Conclusions:

Patients with dRTA may develop growth failure over time. An early diagnosis can ameliorate the prognosis of height. The development of CKD is not rare (37.5% of patients) despite adequate metabolic control.