Prevalence of kidney failure in adults diagnosed with hereditary tubulopathies.

Background: Inherited tubulopathies are rare kidney diseases with few data available in the literature regarding their long-term renal prognosis. This study aimed to evaluate the prevalence of kidney failure in adults with confirmed genetic tubulopathy and to describe the corresponding clinical and genetic findings.
Methods: In this observational cohort study, we focused on genetic tubulopathies assumed to impact kidney function. In all adult patients genetically diagnosed in our laboratory between 2001 and 2019, we estimated Glomerular Filtration Rate (eGFR) at diagnosis using the Modification of diet in renal disease (MDRD) formula. Kidney failure was defined as an eGFR < 60 ml/min/1.73 m ² .
Results: A total of 2145 patients underwent genetic testing, confirming a genetic tubulopathy in 1031 cases (48%). We identified 116 patients out of 885 with available data with kidney failure, mostly diagnosed with Dent disease and distal renal tubular acidosis (respectively, 31% and 20%), followed by familial hypomagnesemia with hypercalciuria and nephrocalcinosis and renal hypophosphatemia/infantile hypercalcemia. Renal prognosis appeared particularly impacted in familial hypomagnesemia with hypercalciuria and nephrocalcinosis and Dent disease, while preserved in Gitelman syndrome.
Conclusion: In this cohort, 13% of adults with genetic tubulopathy had kidney failure at diagnosis, with this rate varying greatly according to tubulopathies and suggesting a significant impact on renal prognosis. Even in adults, genetic analyses yield a good diagnostic rate in selected patients, and should be performed as soon as possible, in order to improve the renal management of patients and their relatives.
(© 2024. The Author(s) under exclusive licence to Italian Society of Nephrology.)