Pseudomyotonia (PMT) in Chianina and Romagnola Cattle

Quick Summary

Congenital pseudomyotonia (PMT) is a recessive genetic defect seen in Chianina and Romagnola cattle that impairs muscle function and is characterized by exercise-induced muscle cramping.

Phenotype: Congenital pseudomyotonia (PMT) is characterized by exercise-induced muscle cramping triggered when affected animals are startled or made to move faster than a slow walk. During cramping episodes, animals present with an uncoordinated gait, sometimes hopping on their back feet. During prolonged exercise, muscles become so stiff that animals fall over and are unable to stand. Cramping episodes cease and normal movement resumes when the stimulation is stopped.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal/Unaffected, PCR = Congenital pseudomyotonia (Chianina and Romagnola), PR = Congenital pseudomyotonia (Romagnola only)

Breeds appropriate for testing: Chianina, Romagnola, BueLingo, Chianina crosses, Romagnola crosses

Explanation of Results:

  • Cattle with N/N genotype will not have congenital pseudomyotonia and cannot transmit these congenital pseudomyotonia variants to their offspring.
  • Cattle with N/PCR or N/PR genotype will not be affected by congenital pseudomyotonia, but are carriers of a congenital pseudomyotonia variant. They will transmit the variant they carry to 50% of their offspring. Matings between two carriers result in a 25% chance of producing a calf with congenital pseudomyotonia.
  • Cattle with PCR/PCR, PR/PR, or PCR/PR genotype will have congenital pseudomyotonia, a genetic condition that impairs muscle function. 
Price

$25 one test per animal

Additional Details

Congenital pseudomyotonia (PMT) is a genetic defect that impairs muscle function. PMT is characterized by exercise-induced muscle cramping triggered when affected animals are startled or made to move faster than a slow walk. During cramping episodes, animals present with an uncoordinated gait, sometimes hopping on their back feet. During prolonged exercise, muscles become so stiff that animals fall over and are unable to stand. Cramping episodes cease and normal movement resumes when the stimulation is stopped. Clinical signs of PMT are present from birth and remain unchanged for life.

The abnormal muscle function in PMT cases results from mutations in the ATPase Sarcoplasmic/Endoplasmic Reticulum Ca2+ Transporting 1 (ATP2A1) gene. This gene encodes an enzyme required for calcium re-uptake by muscle cells and regulation of muscular contraction and relaxation. Three mutations have been identified in cattle that are associated with PMT. These mutations result in amino acid substitutions in the ATP2A1 enzyme that reduce its activity and affect muscle relaxation. The Arg164His mutation (PCR) is found in Chianina and Romagnola breeds. Two linked mutations, [Gly211Val; Gly284Val] (PR), were also identified in Romagnola breed.

PMT is inherited as a recessive trait in cattle. This means that 2 copies of the defective gene are needed to cause the disease. In the Romagnola breed, the 2 defective genes can be of the same mutation (PCR/PCR or PR/PR), or a combination of 2 mutations (PCR/PR). Males and females are equally affected.

Testing for PMT in Chianina and Romagnola breeds helps breeders determine if a PMT mutation is present among breeding stock and implement mating strategies to reduce incidence of PMT while retaining genetic diversity and other desirable attributes of these breeds. Carriers can be safely bred to N/N mates as this type of breeding will not produce affected calves.

Turnaround Time
6 - 10 business days
Type of Sample

Species

Type of Test

Results Reported As
Test Result PMT Mutation

N/N

Normal. No copies of PMT mutations are present.

N/PCR

Carrier. 1 copy of the PCR mutation is present. Animal is normal but can produce affected offspring if bred to another carrier.

N/PR

Carrier. 1 copy of the PR mutation is present. Animal is normal but can produce affected offspring if bred to another carrier.

PCR/PCR

Affected. 2 copies of the PCR mutation.

PR/PR

Affected. 2 copies of the PR mutation.

PCR/PR

Affected. 1 copy each of PCR and PR mutations.
References

Drögemüller, C., Drögemüller, M., Leeb, T., Mascarello, F., Testoni, S., Rossi, M., Gentile, A., & Damiani, E. (2008). Identification of a missense mutation in the bovine ATP2A1 gene in congenital pseudomyotonia of Chianina cattle: an animal model of human Brody disease. Genomics, 92(6), 474-477. doi: 10.1016/j.ygeno.2008.07.014

Sacchetto, R., Testoni, S., Gentile, A., Damiani, E., Rossi, M., Liguori, R., Drögemüller, C., & Mascarello, F. (2009). A defective SERCA1 protein is responsible for congenital pseudomyotonia in Chianina cattle. The American Journal of Pathology, 174(2), 565-573. doi: 10.2353/ajpath.2009.080659

Murgiano, L., Sacchetto, R., Testoni, S., Dorotea, T., Mascarello, F., Liguori, R., Gentile, A., & Drögemüller, C. (2012). Pseudomyotonia in Romagnola cattle caused by novel ATP2A1 mutations. BMC Veterinary Research, 8, 186. doi: 10.1186/1746-6148-8-186

Murgiano, L., Testoni, S., Drögemüller, C., Bolcato, M., & Gentile, A. (2013). Frequency of bovine congenital pseudomyotonia carriers in selected Italian Chianina sires. The Veterinary Journal, 195(2), 238-240. doi: 10.1016/j.tvjl.2012.04.021