A 25-year-old man who arrived at a clinic in China with elevated serum creatinine and uric acid levels has led researchers to identify a previously unreported genetic variant associated with a rare hereditary kidney disorder. The case, described in a case report published in Frontiers in Nephrology, adds a new entry to the growing catalogue of mutations in the UMOD gene, which is responsible for autosomal dominant tubulointerstitial kidney disease caused by UMOD variants, known as ADTKD-UMOD.

ADTKD-UMOD is a rare hereditary disorder characterized by early-onset hyperuricemia, gout, and progressive kidney dysfunction. Diagnosis of ADTKD-UMOD is established by genetic testing. The family history drew the attention of the clinical team at Hebei Province Traditional Chinese Medicine Hospital.

The patient’s father and elder sister both had chronic kidney disease of unknown etiology, a pattern that suggested autosomal dominant inheritance, in which a single copy of a disease-causing variant is sufficient to cause the disorder. Before turning to genetics, the clinicians carried out a comprehensive evaluation to exclude secondary causes of hyperuricemia and kidney dysfunction, ensuring that an inherited condition was the most likely explanation for the family’s illness.

Genetic testing identified a novel heterozygous missense variant in the UMOD gene: c.274T>A, designated p.Cys92Ser, located in exon 3 of the gene (transcript NM_003361.4). The same variant was also detected in the affected relatives, strengthening the link between the mutation and the disease pattern observed in the family.

The variant had not been described before, so the researchers turned to in silico analyses, computational methods that predict whether a genetic change is likely to damage a protein. These analyses predicted a deleterious effect, and following the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) criteria, the team classified the variant as likely pathogenic. The classification rested on a combination of criteria: PM5 and PP3 at moderate strength, and PM2 as supporting evidence.

The location of the change is significant. The p.Cys92Ser substitution replaces a cysteine amino acid with a serine. By analogy to well-characterized pathogenic cysteine-altering UMOD variants, the authors hypothesize that p.Cys92Ser may promote uromodulin misfolding and retention in the endoplasmic reticulum, the cellular compartment where newly made proteins are processed, thereby contributing to kidney injury. The researchers are explicit that this mechanistic inference remains to be verified by direct functional experiments for this novel variant; it is a hypothesis grounded in comparison with other variants, not a demonstrated mechanism for this one.

When UMOD variants interfere with the protein’s folding, the misfolded protein accumulates inside kidney cells, which is thought to drive the tubulointerstitial damage characteristic of the disease. ADTKD-UMOD is characterized by early-onset hyperuricemia, gout, and progressive kidney dysfunction.

During longitudinal follow-up, the patient was treated with febuxostat, a medication that lowers serum urate levels. Over the observational period, his serum urate levels decreased in response to treatment, while his renal function showed progressive deterioration.

The report underscores the importance of early genetic testing in at-risk families. Because the father and sister of the index patient had chronic kidney disease of unknown etiology, identifying the familial variant offers relatives a clearer explanation for their condition and can inform screening of other family members who may carry the same mutation. The authors also emphasize the need for standardized long-term follow-up and management for this progressive disorder, given that kidney function can decline steadily even as urate levels are brought under control.

By documenting this novel variant, the case report expands the known mutational spectrum of ADTKD-UMOD.

Subject of Research: A novel UMOD gene variant identified in a family with autosomal dominant tubulointerstitial kidney disease

Article Title: Case Report: Uromodulin-associated autosomal dominant tubulointerstitial kidney disease: case analysis and literature review

Article References: Zheng, L., Gao, H., Zheng, X., Zhang, X., & Wei, X. (2026). Case Report: Uromodulin-associated autosomal dominant tubulointerstitial kidney disease: case analysis and literature review. Frontiers in Nephrology, 6, Article 1931661. https://doi.org/10.3389/fneph.2026.1931661

Image Credits: AI Generated

DOI: 10.3389/fneph.2026.1931661

Keywords: ADTKD-UMOD, UMOD, uromodulin, genetic testing, hyperuricemia, chronic kidney disease, case report, febuxostat, missense variant, nephrology, gout, inherited kidney disease