title: Whole-exome sequencing improves mutation detection in a diagnostic epidermolysis bullosa laboratory.
abstract: BACKGROUND
  Subtypes of inherited epidermolysis bullosa (EB) vary significantly in their clinical presentation and prognosis. Establishing an accurate diagnosis is important for genetic counselling and patient management. Current approaches in EB diagnostics involve skin biopsy for immunohistochemistry and transmission electron microscopy, and Sanger sequencing of candidate genes. Although informative in most cases, this approach can be expensive and laborious and may fail to identify pathogenic mutations in ~15% of cases.
  
  
  OBJECTIVE
  Next-generation DNA sequencing (NGS) technologies offer a fast and efficient complementary diagnostic strategy, but the value of NGS in EB diagnostics has yet to be explored. The aim of this study was to undertake whole-exome sequencing (WES) in nine cases of EB in which established diagnostic methods failed to make a genetic diagnosis.
  
  
  METHODS
  Whole-exome capture was performed using genomic DNA from each case of EB, followed by massively parallel sequencing. Resulting reads were mapped to the human genome reference hg19. Potentially pathogenic mutations were subsequently confirmed by Sanger sequencing.
  
  
  RESULTS
  Analysis of WES data disclosed biallelic pathogenic mutations in each case, with all mutations occurring in known EB genes (LAMB3, PLEC, FERMT1 and COL7A1). This study demonstrates that NGS can improve diagnostic sensitivity in EB compared with current laboratory practice.
  
  
  CONCLUSIONS
  With appropriate diagnostic platforms and bioinformatics support, WES is likely to increase mutation detection in cases of EB and improve EB diagnostic services, although skin biopsy remains an important diagnostic investigation in current clinical practice.
authors.affiliation: St John's Institute of Dermatology, King's College London (Guy's Campus), London, U.K; Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takeichi
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: K
authors.initials: K
authors.lastname: Fong
authors.forename: L
authors.initials: L
authors.lastname: Ozoemena
authors.forename: J R
authors.initials: JR
authors.lastname: McMillan
authors.forename: A
authors.initials: A
authors.lastname: Salam
authors.forename: P
authors.initials: P
authors.lastname: Campbell
authors.forename: M
authors.initials: M
authors.lastname: Akiyama
authors.forename: J E
authors.initials: JE
authors.lastname: Mellerio
authors.forename: W H I
authors.initials: WH
authors.lastname: McLean
authors.forename: M A
authors.initials: MA
authors.lastname: Simpson
authors.forename: J A
authors.initials: JA
authors.lastname: McGrath
mesh_terms: D000328:Adult; D015815:Cell Adhesion Molecules / Q000235:genetics; D024143:Collagen Type VII / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods*; D004820:Epidermolysis Bullosa / Q000175:diagnosis* / Q000235:genetics; D059472:Exome / Q000235:genetics*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009363:Neoplasm Proteins / Q000235:genetics; D051190:Plectin / Q000235:genetics; D000097794:Kalinin
chemical_list: D015815:Cell Adhesion Molecules; D024143:Collagen Type VII; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D051190:Plectin; D000097794:Kalinin; C569053:COL7A1 protein, human; C475301:FERMT1 protein, human; C495332:PLEC protein, human