Inheritance of hereditary equine regional dermal asthenia in Quarter Horses.
OBJECTIVE
To assess heritability and mode of inheritance for hereditary equine regional dermal asthenia (HERDA) in Quarter Horses.


METHODS
1,295 horses with Quarter Horse bloodlines, including 58 horses affected with HERDA.


METHODS
Horses were classified as affected or unaffected or as undetermined when data were insufficient to assess phenotype. Pedigree data were analyzed to determine the probable mode of inheritance. Heritability was estimated by use of Bayesian statistical methods.


RESULTS
Heritability (mean+/-SD) of HERDA was estimated to be 0.38+/-0.13, with both sexes having an equal probability of being affected. Results for evaluation of the pedigrees were consistent with a single Mendelian autosomal recessive mode of inheritance.


CONCLUSIONS
HERDA in Quarter Horses is an inherited disease, and affected horses are more likely to produce affected offspring. An autosomal recessive mode of inheritance should be considered by people making breeding decisions involving Quarter Horses when a first-degree relative has been confirmed with HERDA or has produced affected offspring. In addition, breeders whose horses have produced affected offspring can reduce the likelihood of producing affected horses in the future by avoiding inbreeding.
Tryon
Robert C
RC
Department of Population Health and Reproduction, University of California, Davis, CA 95616, USA.
White
Stephen D
SD
Famula
Thomas R
TR
Schultheiss
Patricia C
PC
Hamar
Dwayne W
DW
Bannasch
Danika L
DL
D000818:Animals; D001247:Asthenia / Q000235:genetics / Q000662:veterinary*; D001499:Bayes Theorem; D005808:Genes, Recessive / Q000235:genetics; D006734:Horse Diseases / Q000235:genetics*; D006736:Horses; D008954:Models, Biological; D010375:Pedigree; D012873:Skin Diseases, Genetic / Q000662:veterinary*