title: DNA-based diagnosis of rare diseases in veterinary medicine: a 4.4 kb deletion of ITGB4 is associated with epidermolysis bullosa in Charolais cattle.
abstract: BACKGROUND
  Rare diseases in livestock animals are traditionally poorly diagnosed. Other than clinical description and pathological examination, the underlying causes have, for the most part, remained unknown. A single case of congenital skin fragility in cattle was observed, necropsy, histological and ultrastructural examinations were carried out and whole genome sequencing was utilized to identify the causative mutation.
  
  
  RESULTS
  A single purebred female Charolais calf with severe skin lesions was delivered full-term and died spontaneously after birth. The clinical and pathological findings exactly matched the gross description given by previous reports on epitheliogenesis imperfecta and epidermolysis bullosa (EB) in cattle. Histological and ultrastructural changes were consistent with EB junctionalis (EBJ). Genetic analysis revealed a previously unpublished ITGB4 loss-of-function mutation; the affected calf was homozygous for a 4.4 kb deletion involving exons 17 to 22, and the dam carried a single copy of the deletion indicating recessive inheritance. The homozygous mutant genotype did not occur in healthy controls of various breeds but some heterozygous carriers were found among Charolais cattle belonging to the affected herd. The mutant allele was absent in a representative sample of unrelated sires of the German Charolais population.
  
  
  CONCLUSIONS
  This is the first time in which a recessively inherited ITGB4 associated EBJ has been reported in cattle. The identification of heterozygous carriers is of importance in avoiding the transmission of this defect in future. Current DNA sequencing methods offer a powerful tool for understanding the genetic background of rare diseases in domestic animals having a reference genome sequence available.
authors.affiliation: Chemisches und Veterinäruntersuchungsamt Westfalen, Zur Taubeneiche 10-12, 59821, Arnsberg, Germany. martin.peters@cvua-westfalen.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Peters
authors.affiliation: Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001, Bern, Switzerland. reber.irene@bluewin.ch.
authors.forename: Irene
authors.initials: I
authors.lastname: Reber
authors.affiliation: Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001, Bern, Switzerland. vidhya.jagannathan@vetsuisse.unibe.ch.
authors.forename: Vidhya
authors.initials: V
authors.lastname: Jagannathan
authors.affiliation: Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany. barbara.raddatz@tiho-hannover.de.
authors.forename: Barbara
authors.initials: B
authors.lastname: Raddatz
authors.affiliation: Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany. peter.wohlsein@tiho-hannover.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Wohlsein
authors.affiliation: Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001, Bern, Switzerland. cord.droegemueller@vetsuisse.unibe.ch.
authors.forename: Cord
authors.initials: C
authors.lastname: Drögemüller
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000235:genetics; D004820:Epidermolysis Bullosa / Q000175:diagnosis / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D005260:Female; D017353:Gene Deletion; D006720:Homozygote; D039663:Integrin beta4 / Q000235:genetics*; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D012867:Skin / Q000473:pathology / Q000648:ultrastructure
chemical_list: D039663:Integrin beta4