Immature renal structures associated with a novel UMOD sequence variant

Area of Science:

• Nephrology
• Genetics
• Molecular Biology

Background:

• Mutations in the UMOD gene, encoding uromodulin, are linked to various kidney diseases like medullary cystic kidney disease 2 and familial juvenile hyperuricemic nephropathy.
• Uromodulin is a key protein in kidney function and development.

Observation:

• A 13-year-old boy presented with chronic kidney disease, hyperuricemia, and impaired urine concentration.
• Renal biopsy revealed glomerular cysts, interstitial fibrosis, and immature tubules.
• Distinctive immunohistochemical findings included absent uromodulin urinary excretion and no cytoplasmic globular aggregates.

Findings:

• A novel heterozygous UMOD gene variant (c.149G-->C; p.Cys50Ser) was identified in the affected boy and his father.
• This variant affects the first epidermal growth factor-like domain of uromodulin.
• The histological and immunohistochemical findings differed from previously reported UMOD-associated nephropathies.

Implications:

• This novel UMOD variant suggests a potential role for uromodulin in renal development.
• The distinct presentation highlights the diverse clinical and pathological spectrum of UMOD nephropathies.
• Further research into UMOD's developmental role could uncover new therapeutic targets for kidney diseases.