title: TRPC6 single nucleotide polymorphisms and progression of idiopathic membranous nephropathy.
abstract: BACKGROUND
  Activating mutations in the Transient Receptor Potential channel C6 (TRPC6) cause autosomal dominant focal segmental glomerular sclerosis (FSGS). TRPC6 expression is upregulated in renal biopsies of patients with idiopathic membranous glomerulopathy (iMN) and animal models thereof. In iMN, disease progression is characterized by glomerulosclerosis. In addition, a context-dependent TRPC6 overexpression was recently suggested in complement-mediated podocyte injury in e.g. iMN. Hence, we hypothesized that genetic variants in TRPC6 might affect susceptibility to development or progression of iMN.
  
  
  RESULTS
  Genomic DNA was isolated from blood samples of 101 iMN patients and 292 controls. By direct sequencing of the entire TRPC6 gene, 13 single nucleotide polymorphisms (SNPs) were identified in the iMN cohort, two of which were causing an amino acid substitution (rs3802829; Pro15Ser and rs36111323, Ala404Val). No statistically significant differences in genotypes or allele frequencies between patients and controls were observed. Clinical outcome in patients was determined (remission n = 26, renal failure n = 46, persistent proteinuria n = 29, follow-up median 80 months {range 51-166}). The 13 identified SNPs showed no association with remission or renal failure. There were no differences in genotypes or allele frequencies between patients in remission and progressors.
  
  
  CONCLUSIONS
  Our data suggest that TRPC6 polymorphisms do not affect susceptibility to iMN, or clinical outcome in iMN.
authors.affiliation: Department of Nephrology, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Hofstra
authors.affiliation: Department of Human Genetics, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Marieke J H
authors.initials: MJ
authors.lastname: Coenen
authors.affiliation: Department of Human Genetics, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Mascha M V A P
authors.initials: MM
authors.lastname: Schijvenaars
authors.affiliation: Department of Nephrology, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Jo H M
authors.initials: JH
authors.lastname: Berden
authors.affiliation: Department of Nephrology, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: van der Vlag
authors.affiliation: Department of Human Genetics, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Lies H
authors.initials: LH
authors.lastname: Hoefsloot
authors.affiliation: Department of Human Genetics, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Nine V A M
authors.initials: NV
authors.lastname: Knoers
authors.affiliation: Department of Nephrology, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Jack F M
authors.initials: JF
authors.lastname: Wetzels
authors.affiliation: Department of Nephrology, Radboud university medical center, Nijmegen, the Netherlands.
authors.forename: Tom
authors.initials: T
authors.lastname: Nijenhuis
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D018450:Disease Progression; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D015433:Glomerulonephritis, Membranous / Q000235:genetics* / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D050052:TRPC Cation Channels / Q000737:chemistry / Q000235:genetics*; D000074287:TRPC6 Cation Channel
chemical_list: D017931:DNA Primers; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human