title: Altered expression of Crb2 in podocytes expands a variation of CRB2 mutations in steroid-resistant nephrotic syndrome.
abstract: Steroid-resistant nephrotic syndrome (SRNS) is a genetically heterogeneous disorder for which more than 25 single-gene hereditary causes have been identified.
  
  
  
  Whole exome sequencing was performed in a 3-year-old girl with SRNS. We analyzed the expression of Crb2 and slit diaphragm molecules in the patient's glomeruli, and compared it with that of controls or other nephrotic patients.
  
  
  
  Whole-exome analysis identified novel compound heterozygous mutations in exons 10 and 12 of CRB2 (p.Trp1086ArgfsX64 and p.Asn1184Thr, each from different parents; Asn1184 within extracellular 15th EGF repeat domain). Renal pathology showed focal segmental glomerulosclerosis with effaced podocyte foot processes in a small area, with significantly decreased Crb2 expression. Molecules critical for slit diaphragm were well-expressed in this patient's podocytes. Crb2 expression was not altered in the other patients with congenital nephrotic syndrome with NPHS1 mutations.
  
  
  
  These findings demonstrate that Crb2 abnormalities caused by these mutations are the mechanism of steroid-resistant NS. Although CRB2 mutations previously found in SRNS patients have been clustered within the extracellular tenth EGF-like domain of this protein, the present results expand the variation of CRB2 mutations that cause SRNS.
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Udagawa
authors.affiliation: Department of Pediatrics, Nippon Medical School, Tokyo, Japan.
authors.forename: Tohaku
authors.initials: T
authors.lastname: Jo
authors.affiliation: Department of Pediatrics, Nippon Medical School, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagihara
authors.affiliation: Department of Analytic Human Pathology, Nippon Medical School, Bunkyo-ku, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Shimizu
authors.affiliation: Department of Neurology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Mitsui
authors.affiliation: Department of Neurology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuji
authors.affiliation: Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Morishita
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Onai
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Miura
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Kanda
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kajiho
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Tsurumi
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Oka
authors.affiliation: Department of Pediatric Nephrology, Tokyo Women's Medical University, Sinjuku-ku, Tokyo, Japan.
authors.forename: Motoshi
authors.initials: M
authors.lastname: Hattori
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. haritay-ped@h.u-tokyo.ac.jp.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Harita
mesh_terms: D000893:Anti-Inflammatory Agents; D002352:Carrier Proteins / Q000235:genetics*; D002675:Child, Preschool; D004351:Drug Resistance; D059472:Exome / Q000235:genetics; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D005923:Glomerulosclerosis, Focal Segmental / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D007678:Kidney Glomerulus / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D009404:Nephrotic Syndrome / Q000235:genetics*; D050199:Podocytes / Q000378:metabolism*; D013256:Steroids / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; C492531:CRB2 protein, human; D002352:Carrier Proteins; D008565:Membrane Proteins; D013256:Steroids; C113267:nephrin
keywords: Crb2; Podocyte; Slit diaphragm; Steroid-resistant nephrotic syndrome