CANDID Study: Clinical and Molecular Characterization of Congenital Arginine Vasopressin-Resistance and the Use of a Novel Diagnostic Biomarker in Indian Children.

Objectives: To present authors' experience with congenital arginine vasopressin resistance (AVP-R) in children up to 12-y-old at a tertiary care center in Northern India.

Methods: An ambispective analysis was conducted, focusing on clinical, biochemical, genetic evaluations, treatments, renal and neurological outcomes.

Results: Data from 11 patients (two females) were included, with an average delay of 18 mo between symptom onset and diagnosis. The majority of children presented with failure to thrive (90.9%), polyuria (90.9%), and hyperosmolality (63.6%) at the time of diagnosis. Nearly one-fourth of the cohort experienced acute kidney injury. Random copeptin levels (340.7 ± 59.56 pmol/L) were significantly higher than the diagnostic cutoff suggested in the literature, and molecular diagnosis confirmed AVPR2 mutations in 90% of the cases. The subjects were followed for a median of 2.1 y (range: 1-4.7 y). During this period, there was a median increase of + 0.79 in BMI/weight-for-height SDS and a 30.55% reduction in urine output. However, 63.63% of the children continued to experience failure to thrive. None of the subjects developed renal structural abnormalities or chronic kidney disease (CKD) ≥ stage 2 by the final follow-up. Neurological evaluation revealed attention deficit hyperactivity disorder and gross developmental delay in two children and one child respectively.

Conclusions: This study provides the first comprehensive analysis of congenital AVP-R in a low-middle-income setting.