title: Genotype-Phenotype Correlation for TGFBI Corneal Dystrophies Identifies p.(G623D) as a Novel Cause of Epithelial Basement Membrane Dystrophy.
abstract: OBJECTIVE
  The majority of anterior corneal dystrophies are caused by dominant mutations in TGFBI (transforming growth factor β-induced) collectively known as the epithelial-stromal TGFBI dystrophies. Most cases of epithelial basement membrane dystrophy (EBMD) are thought to result from a degenerative (nongenetic) process; however, a minority of cases are associated with specific TGFBI mutations. We evaluated the spectrum of TGFBI mutations and associated phenotypes in a United Kingdom cohort with typical epithelial-stromal TGFBI dystrophies and an EBMD cohort.
  
  
  METHODS
  We recruited 68 probands with a clinical diagnosis of epithelial-stromal TGFBI dystrophy and 23 probands with bilateral EBMD. DNA was extracted from peripheral leukocytes, and TGFBI was bi-directly Sanger sequenced.
  
  
  RESULTS
  Nine TGFBI mutations were identified. The most common occurred at the mutation hot-spot residues R124 and R555 in 61 probands; these individuals had a genotype-phenotype correlation consistent with prior reports. Four probands with lattice corneal dystrophy carried a mutation in exon 14: p.(A620D), p.(V625D), and p.(H626R). We identified a p.(G623D) mutation in five probands, including two probands from the EBMD cohort. These subjects typically had an onset of severe recurrent corneal epithelial erosion in the fourth decade with mild diffuse or geographic subepithelial corneal opacities and only small anterior stromal lattice structures in older individuals. Symptoms of painful epithelial erosion improved markedly following phototherapeutic keratectomy.
  
  
  CONCLUSIONS
  There was a strong correlation between genotype and phenotype for the majority of TGFBI mutations. In this cohort, the p.(G623D) mutation caused a greater proportion of TGFBI-associated disease than anticipated, associated with variable phenotypes including individuals diagnosed with EBMD.
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom.
authors.forename: Cerys J
authors.initials: CJ
authors.lastname: Evans
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom.
authors.forename: Alice E
authors.initials: AE
authors.lastname: Davidson
authors.affiliation: Moorfields Eye Hospital, London, United Kingdom 3Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Carnt
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom.
authors.forename: Karla E
authors.initials: KE
authors.lastname: Rojas López
authors.affiliation: Moorfields Eye Hospital, London, United Kingdom.
authors.forename: Neyme
authors.initials: N
authors.lastname: Veli
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Thaung
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Tuft
authors.affiliation: University College London (UCL), Institute of Ophthalmology, London, United Kingdom.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Hardcastle
mesh_terms: D000328:Adult; D001485:Basement Membrane / Q000378:metabolism / Q000473:pathology*; D003315:Cornea / Q000378:metabolism / Q000473:pathology*; D003317:Corneal Dystrophies, Hereditary / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D008297:Male; D033401:Microscopy, Acoustic; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism
chemical_list: C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; D004247:DNA