Immature Renal Structures Associated With a Novel UMOD Sequence Variant

Elisa Benetti, Gianluca Caridi, Manuela Della Vella, Luca Rampoldi, Gian Marco Ghiggeri, Lina Artifoni, Luisa Murer

Research output: Contribution to journalArticlepeer-review

Abstract

Mutations of the UMOD gene, encoding uromodulin, have been associated with medullary cystic kidney disease 2, familial juvenile hyperuricemic nephropathy, and glomerulocystic kidney disease. We report on a 13-year-old boy presenting with chronic reduced kidney function, hyperuricemia, and impairment in urine-concentrating ability. His father was affected by an undefined nephropathy that required transplantation. The boy's renal ultrasonography showed reduced bilateral kidney volumes and cortical hyperechogenicity, with 2 tiny cysts in the left kidney. Renal biopsy showed up to 60% of glomeruli featuring an enlargement of Bowman space (glomerular cysts), with mild interstitial fibrosis (alpha-smooth muscle actin [αSMA] positive), inflammatory infiltrate, and focal tubular atrophy at the cortical level. At the corticomedullary junction, immature tubules (some dilated) with cytokeratin- and paired box gene 2 (PAX2)-positive immunostaining were seen, surrounded by vimentin-positive mesenchymal tissue. Unlike previously reported cases, no uromodulin-positive globular aggregates within the cytoplasm of tubular cells were observed. Uromodulin urinary excretion was absent. Genetic analysis showed a novel heterozygous sequence change in the UMOD gene (NM_003361.2:c.149G→C; p.Cys50Ser) involving the first epidermal growth factor-like domain of the protein in both the boy and his father. This novel UMOD sequence variant, which is associated with an immunohistochemical pattern different from previous reports and a histological picture characterized by immature renal structures, suggests a possible role for UMOD in renal development.

Original languageEnglish
Pages (from-to)327-331
Number of pages5
JournalAmerican Journal of Kidney Diseases
Volume53
Issue number2
DOIs
Publication statusPublished - Feb 2009

Keywords

  • glomerulocystic kidney disease
  • juvenile hyperuricemic nephropathy
  • medullary cystic disease type 2
  • renal development
  • renal dysplasia
  • Uromodulin

ASJC Scopus subject areas

  • Nephrology

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