Exclusion of linkage of the RYR1, CACNA1S, and ATP2A1 genes to recurrent exertional rhabdomyolysis in Thoroughbreds.
OBJECTIVE
To determine whether there was genetic linkage between the recurrent exertional rhabdomyolysis (RER) trait in Thoroughbred horse pedigrees and DNA markers in genes (the sarcoplasmic reticulum calcium release channel [RYR1] gene, the sarcoplasmic reticulum calcium ATPase [ATP2A1] gene, and the transverse tubule dihydropyridine receptor-voltage sensor [CACNA1S] gene) that are important in myoplasmic calcium regulation.


METHODS
34 horses in the University of Minnesota RER resource herd and 62 Thoroughbreds from 3 families of Thoroughbreds outside of the university in which RER-affected status was assigned after 2 or more episodes of ER had been observed.


METHODS
Microsatellite DNA markers from the RYR1, ATP2A1, and CACNA1S gene loci on equine chromosomes 10, 13, and 30 were identified. Genotypes were obtained for all horses in the 4 families affected by RER, and data were used to test for linkage of these 3 loci to the RER phenotype.


RESULTS
Analysis of the RYR1, CACNA1S, and ATP2A1 microsatellites excluded a link between those markers and the RER trait.


CONCLUSIONS
It is likely that the heritable alterations in muscle contractility that are characteristic of RER are caused by a gene that is not yet known to cause related muscle disease in other species.
Dranchak
Patricia K
PK
Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, 55108, USA.
Valberg
Stephanie J
SJ
Onan
Gary W
GW
Gallant
Esther M
EM
Binns
Matthew M
MM
Swinburne
June E
JE
Mickelson
James R
JR
D000818:Animals; D015220:Calcium Channels / Q000235:genetics*; D000252:Calcium-Transporting ATPases / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006734:Horse Diseases / Q000235:genetics*; D006736:Horses; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D012206:Rhabdomyolysis / Q000235:genetics / Q000662:veterinary*
D015220:Calcium Channels; D005819:Genetic Markers; D000252:Calcium-Transporting ATPases