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Kidney Week

Abstract: SA-PO616

The Comprehensive Gene Screening for Congenital, Infantile, and Steroid Resistant Nephrotic Syndrome in Japan

Session Information

Category: Genetic Diseases of the Kidney

  • 803 Genetic Epidemiology and Other Genetic Studies of Common Kidney Diseases

Authors

  • Nakanishi, Keita, Kobe University Graduate School of Medicine, Kobe, Japan
  • Nozu, Kandai, Kobe University, Kobe, Japan
  • Fujimura, Junya, Kobe University Graduate School of Medicine, Kobe, Japan
  • Minamikawa, Shogo, Kobe University Graduate School of Medicine, Kobe, Japan
  • Yamamura, Tomohiko, Kobe University Graduate School of Medicine, Kobe, Japan
  • Kaito, Hiroshi, None, Kobe, Japan
  • Shima, Yuko, Wakayama Medical University, Wakayama City, Japan
  • Nakanishi, Koichi, Graduate School of Medicine, University of the Ryukyus, Nishihara-cho, Japan
  • Iijima, Kazumoto, Dept. of Pediatrics, Kobe Univ. Graduate School of Medicine, Kobe, Japan
Background

Cases with congenital nephrotic syndrome (CNS), infantile nephrotic syndrome (INS) or steroid-resistant nephrotic syndrome (SRNS) frequently progress to end stage renal disease (ESRD). It has been reported that about thirty percent of CNS/INS/SRNS patients possessed single causative gene variants in podocyte related genes that were detected by next generation sequencing. It has been revealed CNS/INS/SRNS patients with gene defects show severe renal prognosis; however, those patients seldom show recurrence of nephrotic syndrome after kidney transplantation. Thus, we established a gene screening system for CNS/INS/SRNS patients in their early stages, to suggest their clinical courses.

Methods

The gene screening system by targeted sequencing for 45 podocyte related genes that have been reported as causative genes for CNS/INS/SRNS was established. Newly diagnosed patients as CNS/INS/SRNS were recruited between January in 2016 and May in 2017.

Results

In total, 84 patients from 42 hospitals in Japan were screened. We detected causative genes in 25 patients (30%). The most frequent gene was WT1 (4 patients), and other genes were LAMB2 (3 patients), ADCK4, TRPC6, LMX1B, INF2, NUP107 (2 patients each), and so on. None of our cases possessed NPHS2 gene variants, which is most common causative gene in European countries. Seven out of 25 patients progressed to ESRD, and only one patient who had TRPC6 variant had kidney transplantation and showed no recurrence of nephrotic syndrome. The cost of gene screening for one sample was about 250.00 (USD).

Conclusion

We have established a comprehensive gene screening system for CNS/INS/SRNS cases in their early disease stages in Japan and detected a single causative gene in 30% in our cohort. The variation of causative genes in Japan was different from those in other countries. The screening results will be used in deciding treatment and thereby help to improve the quality of life for patients.