title: Nonfunction of the ECT2 gene may cause renal tubulointerstitial injury leading to focal segmental glomerulosclerosis.
abstract: BACKGROUND
  Secondary focal segmental glomerulosclerosis (FSGS) follows congenital or acquired tubulointerstitial alterations such as in Dent's disease, Lowe syndrome, and reflux nephropathy. Failure of adequate regeneration after tubulointerstitial injury, or abnormal tubulogenesis, can disturb intrarenal blood circulation, causing excessive glomerular filtration. The epithelial cell-transforming sequence 2 gene (ECT2) contributes to tight junction function in epithelial cells.
  
  
  METHODS
  We encountered two patients with a nonfunctioning ECT2 genotype who later developed FSGS. Both developed proteinuria associated with acute renal failure in early childhood.
  
  
  RESULTS
  Renal biopsy specimens showed marked tubulointerstitial nephritis at the onset of proteinuria, later progressing to FSGS consequent to tubulointerstitial injury. The patients did not respond to corticosteroids and attained only incomplete remission upon cyclosporine A administration. One patient received a maternal renal transplant with good function and no rejection.
  
  
  CONCLUSIONS
  ECT2 is important for tight junction function and maintenance of cell polarity. Nonfunction of this gene may cause renal tubulointerstitial injury, progressing to glomerular sclerosis.
authors.affiliation: Department of Pediatrics, Kinki University School of Medicine, 377-2 Ohno-higashi, Osaka-Sayama 589-8511, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Izu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Fujita
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nishi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takemura
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Okada
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Takemura
mesh_terms: D001706:Biopsy; D002648:Child; D016572:Cyclosporine / Q000627:therapeutic use; D018450:Disease Progression; D004847:Epithelial Cells / Q000502:physiology; D005838:Genotype; D005923:Glomerulosclerosis, Focal Segmental / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation; D008297:Male; D009395:Nephritis, Interstitial / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000502:physiology*; D019108:Tight Junctions / Q000502:physiology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: C489850:ECT2 protein, human; D011518:Proto-Oncogene Proteins; D016572:Cyclosporine