title: Genome-wide linkage study of atopic dermatitis in West Highland White Terriers.
abstract: BACKGROUND
  Canine atopic dermatitis (AD) is a common, heritable, chronic allergic skin condition prevalent in the West Highland White Terrier (WHWT). In canine AD, environmental allergens trigger an inflammatory response causing visible skin lesions and chronic pruritus that can lead to secondary bacterial and yeast infections. The disorder shares many of the clinical and histopathological characteristics of human AD and represents an animal model of this disorder that could be used to further elucidate genetic causes of human AD. Microsatellite markers genotyped in families of WHWTs affected with AD were used to perform a genome-wide linkage study in order to isolate chromosomal regions associated with the disorder.
  
  
  RESULTS
  Blood samples and health questionnaires were collected from 108 WHWTs spanning three families. A linkage simulation using these 108 dogs showed high power to detect a highly penetrant mutation. Ninety WHWTs were genotyped using markers from the Minimal Screening Set 2 (MSS-2). Two hundred and fifty six markers were informative and were used for linkage analysis. Using a LOD score of 2.7 as a significance threshold, no chromosomal regions were identified with significant linkage to AD. LOD scores greater than 1.0 were located in a 56 cM region of chromosome 7.
  
  
  CONCLUSIONS
  The study was unable to detect any chromosomal regions significantly linked to canine AD. This could be a result of factors such as environmental modification of phenotype, incorrect assignment of phenotype, a mutation of low penetrance, or incomplete genome coverage. A genome-wide SNP association study in a larger cohort of WHWTs may prove more successful by providing higher density coverage and higher statistical power.
authors.affiliation: College of Veterinary Medicine, Department of Genetics, North Carolina State University, Raleigh, NC 27606, USA.
authors.forename: Cary A
authors.initials: CA
authors.lastname: Salzmann
authors.forename: Thierry J M
authors.initials: TJ
authors.lastname: Olivry
authors.forename: Dahlia M
authors.initials: DM
authors.lastname: Nielsen
authors.forename: Judith S
authors.initials: JS
authors.lastname: Paps
authors.forename: Tonya L
authors.initials: TL
authors.lastname: Harris
authors.forename: Natasha J
authors.initials: NJ
authors.lastname: Olby
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D003876:Dermatitis, Atopic / Q000235:genetics* / Q000662:veterinary*; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D008040:Genetic Linkage; D005838:Genotype