Introduction: Autosomal dominant tubulointerstitial kidney disease (ADTKD) involves gene mutations that lead to progressive kidney disease, with associated acidosis, hyperkalemia, anemia, and episodes of gout.A heterozygous pathogenic REN genetic variant is present in affected people.Fifty percent of the relatives of patients with ADTKD are also affected, and genetic testing is used to confirm the diagnosis.Methods: We report a 23-year-old man with ADTKD and a heterozygous missense mutation variation of the REN gene.To our knowledge, this variant has not been reported previously.The patient had a family history of kidney disease and hyperuricemia, and he presented with decreased renal function.Results: Magnetic resonance imaging indicated isointense signals in the renal cortices, indicating high water content, as with cysts.However, this finding differed from findings in other cystic renal diseases, which appear as high-intensity signals on T2-weighted magnetic resonance imaging.Renal biopsy in the present case revealed dilated cyst-like structures with fibrosis and positive staining for GATA binding protein 3, which indicated a uroepithelial origin. Conclusion:We speculate that the water-containing tubular structures seen in this patient may be characteristic of ADTKD-REN.I have no potential conflict of interest to disclose.I did not use generative AI and AI-assisted technologies in the writing process.
Ishii et al. (Wed,) studied this question.