Association of a mutation in the ryanodine receptor 1 gene with equine malignant hyperthermia.
Equine malignant hyperthermia MH has been suspected but never genetically confirmed. In this study, we investigated whether mutations in a candidate gene, RyR1, were associated with MH in two clinically affected horses. RyR1 gene sequences revealed polymorphisms in exons 15, 17, and 46 in WTRyR1 and MHRyR1 horses with one derived amino acid change in MHRyR1 exon 46, R2454G. The MHRyR1 horses were genetically heterozygous for this mutation, but presented an MH phenotype with halothane challenge. Skeletal sarcoplasmic reticulum from a R2454G heterozygote collected during a fulminant MH episode showed significantly higher affinity and density of [3H]ryanodine-binding sites compared to WTRyR1, but no differences in Ca2+, Mg2+, and caffeine modulation. In conclusion, an autosomal missense mutation in RyR1 is associated with MH in the horse, providing a screening test for susceptible individuals. [3H]ryanodine-binding analysis suggests that long-lasting changes in RyR1 conformation persists in vitro after the triggering event.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, California 95616, USA. mraleman@ucdavis.edu
Monica
M
Aleman
Joyce
J
Riehl
Brian M
BM
Aldridge
Richard A
RA
Lecouteur
Jeffrey L
JL
Stott
Isaac N
IN
Pessah
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006651:Histocytochemistry; D006734:Horse Diseases / Q000235:genetics* / Q000378:metabolism; D006736:Horses; D008305:Malignant Hyperthermia / Q000235:genetics* / Q000378:metabolism / Q000662:veterinary*; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics* / Q000378:metabolism
D020033:Protein Isoforms; D019837:Ryanodine Receptor Calcium Release Channel