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Kidney Week

Abstract: FR-PO1039

Autosomal Dominant Tubulointerstitial Kidney Diseases: A Single Center Five-Year Cohort

Session Information

Category: Genetic Diseases of the Kidney

  • 1001 Genetic Diseases of the Kidney: Cystic

Authors

  • Gameiro, Joana, Centro Hospitalar Lisboa Norte, Lisbon, Portugal
  • Lopes, Jose António, Centro Hospitalar Lisboa Norte, Lisbon, Portugal
  • Jorge, Sofia C.a., Portuguese Society of Nepghrology, Lisbon, Portugal
Background

In patients with chronic kidney disease of unknown cause, certain aspects of clinical history, urinalysis and renal ultrasound might point to hereditary chronic interstitial nephritis (CIN). Recent sequencing technologies, such as Next-Generation Sequencing (NGS), have been used to identify and characterize different genetic kidney diseases, difficult to diagnose up until recently.
The authors present this single center cohort of patients with identified mutations in genes responsible for autosomal dominant tubulointerstitial kidney diseases (ADTKD) in the last 5 years.

Methods

Over the last five years, when patients with CKD of unknown cause presented with a phenotype suggestive of CIN, NGS study of the UMOD, REN and HNF1B genes was performed, if negative, variable number tandem repeat (VNTR) mutations of the MUC1 gene were researched, if negative, multiplex ligation-dependent probe amplification (MLPA) was performed to find further mutations of the HNF1B gene.

Results

In the past five years, our department has identified ADTKD in 22 patients. Mutations identified included UMOD gene in 2 families (c.1463G>A (p.Gly488Asp); c.628G>A (p.Gly210Ser)) and 1 patient (c.859T>C (p.Cys287Arg)), MUC1 gene in 4 families, REN gene in 1 patient with two variants one of them not described yet (c.29G>A e c.338C>T), and HNF1β gene in 2 patients.

Conclusion

A suggestive phenotype includes bland urinalysis, hyperuricemia without proportion to the CKD stage, anemia not proportional to the CKD stage, hypercalemia, acidemia, urinary concentration defects, normal to low blood pressure and medullary renal cysts. Although some clinical manifestations might suggest a specific gene, many clinical aspects of different gene mutations might have a similar phenotype.
NGS technology is promising in improving the approach to patients with hereditary CKD, and has allowed us to diagnose several patients with CKD of unknown cause. The availability, celerity and cost-effectiveness of this approach make it advantageous over the sequential study of each gene with Sanger sequencing technique. The generalization of these technologies to identify genetic diseases requires consistent identification of phenotypes and integration of data obtained. Therefore, the creation of diagnostic panels is crucial to increase diagnostic accuracy.