title: Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995-2010).
abstract: OBJECTIVE
  To determine the proportion of mixed-breed and purebred dogs with common genetic disorders.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  27,254 dogs with an inherited disorder.
  
  
  METHODS
  Electronic medical records were reviewed for 24 genetic disorders: hemangiosarcoma, lymphoma, mast cell tumor, osteosarcoma, aortic stenosis, dilated cardiomyopathy, hypertrophic cardiomyopathy, mitral valve dysplasia, patent ductus arteriosus, ventricular septal defect, hyperadrenocorticism, hypoadrenocorticism, hypothyroidism, elbow dysplasia, hip dysplasia, intervertebral disk disease, patellar luxation, ruptured cranial cruciate ligament, atopy or allergic dermatitis, bloat, cataracts, epilepsy, lens luxation, and portosystemic shunt. For each disorder, healthy controls matched for age, body weight, and sex to each affected dog were identified.
  
  
  RESULTS
  Genetic disorders differed in expression. No differences in expression of 13 genetic disorders were detected between purebred dogs and mixed-breed dogs (ie, hip dysplasia, hypo- and hyperadrenocorticism, cancers, lens luxation, and patellar luxation). Purebred dogs were more likely to have 10 genetic disorders, including dilated cardiomyopathy, elbow dysplasia, cataracts, and hypothyroidism. Mixed-breed dogs had a greater probability of ruptured cranial cruciate ligament.
  
  
  CONCLUSIONS
  Prevalence of genetic disorders in both populations was related to the specific disorder. Recently derived breeds or those from similar lineages appeared to be more susceptible to certain disorders that affect all closely related purebred dogs, whereas disorders with equal prevalence in the 2 populations suggested that those disorders represented more ancient mutations that are widely spread through the dog population. Results provided insight on how breeding practices may reduce prevalence of a disorder.
authors.affiliation: Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Bellumori
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Famula
authors.forename: Danika L
authors.initials: DL
authors.lastname: Bannasch
authors.forename: Janelle M
authors.initials: JM
authors.lastname: Belanger
authors.forename: Anita M
authors.initials: AM
authors.lastname: Oberbauer
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D020022:Genetic Predisposition to Disease; D006824:Hybridization, Genetic