title: Mutational spectrum of the ZEB1 gene in corneal dystrophies supports a genotype-phenotype correlation.
abstract: OBJECTIVE
  Mutations in ZEB1 have been reported in posterior polymorphous corneal dystrophy (PPCD3; MIM #609141) and Fuchs' endothelial corneal dystrophy (FECD6; MIM #613270). Although PPCD and keratoconus are clinically and pathologically distinct, PPCD has been associated with keratoconus, suggesting a common genetic basis. The purpose of our study was to perform mutational screening of the ZEB1 gene in patients affected with keratoconus or PPCD.
  
  
  METHODS
  Sanger sequencing of ZEB1 was performed in 70 unrelated patients with keratoconus and 18 unrelated patients with PPCD. Real-time quantitative PCR (RT-qPCR) was performed on RNA from cultured corneal keratocytes obtained from a keratoconic patient harboring a missense ZEB1 mutation (p.Gln640His) undergoing corneal transplantation.
  
  
  RESULTS
  Mutational analysis of ZEB1 in PPCD identified a previously reported frameshift mutation (C.1578_1579INSG) and a novel nonsense mutation (C.2249C A) in exon 7 of ZEB1 causing the insertion of a stop codon: p.Ser750X. In the keratoconus cohort, a novel heterozygous pathogenic mutation in exon 7 (c.1920G > T; p.Gln640His) of ZEB1 was identified in a family affected with keratoconus and Fuchs' endothelial corneal dystrophy. RT-qPCR performed on cultured corneal keratocytes harboring the missense ZEB1 mutation (p.Gln640His) demonstrated that COL4A1 and COL4A2 were markedly downregulated, and COL4A3, COL4A4, and COL8A2 were moderately downregulated.
  
  
  CONCLUSIONS
  Our data combined with the previously reported mutational spectrum of ZEB1 support a genotypephenotype correlation: missense substitutions in the ZEB1 protein are associated with FECD6 and keratoconus, whereas protein truncating ZEB1 mutations result in PPCD3. The dysregulation of α-type IV collagens represents a common link between ZEB1 mutation and the clinical phenotypes (PPCD3, FECD, and keratoconus).
authors.affiliation: Centre for Vision and Vascular Science, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Judith
authors.initials: J
authors.lastname: Lechner
authors.forename: Durga P
authors.initials: DP
authors.lastname: Dash
authors.forename: Dorota
authors.initials: D
authors.lastname: Muszynska
authors.forename: Mohsen
authors.initials: M
authors.lastname: Hosseini
authors.forename: Fani
authors.initials: F
authors.lastname: Segev
authors.forename: Sonia
authors.initials: S
authors.lastname: George
authors.forename: David G
authors.initials: DG
authors.lastname: Frazer
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Moore
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kaye
authors.forename: Terri
authors.initials: T
authors.lastname: Young
authors.forename: David A
authors.initials: DA
authors.lastname: Simpson
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Churchill
authors.forename: Elise
authors.initials: E
authors.lastname: Héon
authors.forename: Colin E
authors.initials: CE
authors.lastname: Willoughby
mesh_terms: D000328:Adult; D001483:Base Sequence; D002478:Cells, Cultured; D024141:Collagen Type IV / Q000235:genetics; D024102:Collagen Type VIII / Q000235:genetics; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics* / Q000601:surgery; D060527:Corneal Keratocytes / Q000378:metabolism; D019781:Corneal Topography; D016039:Corneal Transplantation; D004252:DNA Mutational Analysis; D005260:Female; D005642:Fuchs' Endothelial Dystrophy / Q000235:genetics* / Q000601:surgery; D056726:Genetic Association Studies; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007640:Keratoconus / Q000235:genetics* / Q000601:surgery; D008297:Male; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*; D000071799:Zinc Finger E-box-Binding Homeobox 1; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D024141:Collagen Type IV; D024102:Collagen Type VIII; D018398:Homeodomain Proteins; D014157:Transcription Factors; C486307:ZEB1 protein, human; D000071799:Zinc Finger E-box-Binding Homeobox 1
keywords: Fuchs' endothelial dystrophy; ZEB1; corneal dystrophies; hereditary; keratoconus; posterior polymorphous corneal dystrophy