Structured Application of Genetic Testing in a Pediatric Kidney Clinic.

Abstract

BACKGROUND The expanding knowledge of identifiable genetic contributions to pediatric inherited kidney diseases and the increasing availability of genetic testing resources necessitate a combined nephrogenetics clinical approach. While such models are described for adults, the impact of a structured nephrogenetics workflow on children with inherited kidney disease has not been rigorously evaluated. METHODS Clinical and genetic data of patients aged <1 - 21 years a 10-year period between 2014-2024 from a single-center pediatric inherited kidney disease outpatient program was evaluated. Genetic variants were classified as pathogenic/likely pathogenic and variants of uncertain significance (VUS). Patients were grouped into 'informative' or 'uninformative' groups based on the impact of genetic test results on disease management and outcomes. RESULTS Of the N=356 patients evaluated for a known or suspected inherited kidney disease, N=188 received clinical genetic testing. Of these, N=147 had an 'informative' genetic test affecting at least one positive clinical outcome. Patients with an 'informative' genetic test mostly harbored a pathogenic/likely pathogenic variant (N=122). An additional N=25 had a VUS re-classified as a 'VUS-of-interest' affecting a positive outcome measure. Genetic test results led to change in clinical diagnosis (reverse phenotyping, 46%), informed specific diagnosis-based treatment (46%), avoided unnecessary immunosuppression (27%) or kidney biopsy (18%) and guided extrarenal evaluation (72%) in patients with an informative test. Patients with a glomerular (OR=5.23, 95% confidence interval (CI) 1.96-13.96 ) or a tubular functional disease (OR=2.17, 95% CI 1.31-5.59) were more likely and those with a structural kidney disease (OR=0.39, 95% CI 0.25-0.60 ) were less likely to receive a genetic test when compared to all other disease categories combined. CONCLUSIONS This workflow integrated multidisciplinary care for children with inherited kidney disease and describes a model for actionable clinical care plans after genetic testing. Informative genetic tests were associated with positive outcomes and notable challenges include access to combined nephrology and genetics expertise for informed testing and an effective result return including VUS interpretation.