Boyko AR, Brooks SA, Behan-Braman A, Castelhano M, Corey E, Oliveira KC, Swinburne JE, Todhunter RJ, Zhang Z, Ainsworth DM, Robinson NE. Genomic analysis establishes correlation between growth and laryngeal neuropathy in Thoroughbreds.
BMC Genomics 2014;
15:259. [PMID:
24707981 PMCID:
PMC4051171 DOI:
10.1186/1471-2164-15-259]
[Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 03/24/2014] [Indexed: 11/21/2022] Open
Abstract
Background
Equine recurrent laryngeal neuropathy (RLN) is a bilateral mononeuropathy
with an unknown pathogenesis that significantly affects performance in
Thoroughbreds. A genetic contribution to the pathogenesis of RLN is
suggested by the higher prevalence of the condition in offspring of
RLN-affected than unaffected stallions. To better understand RLN
pathogenesis and its genetic basis, we performed a genome-wide association
(GWAS) of 282 RLN-affected and 268 control Thoroughbreds.
Results
We found a significant association of RLN with the
LCORL/NCAPG locus on ECA3 previously shown to affect
body size in horses. Using height at the withers of 505 of these horses, we
confirmed the strong association of this locus with body size, and
demonstrated a significant phenotypic and genetic correlation between height
and RLN grade in this cohort. Secondary genetic associations for RLN on
ECA18 and X did not correlate with withers height in our cohort, but did
contain candidate genes likely influencing muscle physiology and growth:
myostatin (MSTN) and integral membrane protein 2A
(ITM2A).
Conclusions
This linkage between body size and RLN suggests that selective breeding to
reduce RLN prevalence would likely reduce adult size in this population.
However, our results do not preclude the possibility of modifier loci that
attenuate RLN risk without reducing size or performance, or that the RLN
risk allele is distinct but tightly linked to the body size locus on ECA3.
This study is both the largest body size GWAS and the largest RLN GWAS
within Thoroughbred horses to date, and suggests that improved understanding
of the relationship between genetics, equine growth rate, and RLN prevalence
may significantly advance our understanding and management of this
disease.
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