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Cavalier King Charles Spaniels Muscular Dystrophy (CKCS-MD)
| Acronym: | CKCS-MD, CKCSMD, DMD |
| Gene: | DMD1 |
| Mutation: | c.7294+5G>T |
| Inheritance: | X-linked recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Cavalier King Charles Spaniels Muscular Dystrophy (CKCS-MD) is an X-linked recessive disorder in which the loss of dystrophin causes progressive muscle weakness, respiratory insufficiency, and cardiomyopathy. Since males have only one X chromosome, they are more susceptible to inheriting Cavalier King Charles Spaniels Muscular Dystrophy because they need only one parent to pass the gene to them. For females to inherit the gene, both parents must carry it. Females are more often only carriers of the gene. Dystrophin, a cytoskeletal protein located between the extracellular matrix and inner cytoskeleton of muscle fibers. It stiffens muscle fibers, acting as a type of shock absorber by providing resistance against deformation. A deficiency of dystrophin leaves the fibers susceptible to contraction-induced micro fissures, which disrupt calcium homeostasis, ultimately resulting in cellular necrosis. Affected dogs suffer from raised serum creatine kinase levels, muscle atrophy with contractures, hyaline myofiber degeneration with mineralization, endomysial and perimysial fibrosis with fatty infiltration, and cardiomyopathy.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (female) or hemizygous state (male) (i.e. only healthy allele on X chromosome). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has mutated allele in homozygous state (female) or hemizygous state (male) (i.e. only mutated allele on X chromosome). It is likely the animal will experience a genetic disorder due to this mutation.**It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Penetrance of tested mutation, and potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Brinkmeyer-Langford, C., and Kornegay, J.N. (2013). Comparative Genomics of X-linked Muscular Dystrophies: The Golden Retriever Model. Curr Genomics 14, 330–342.
Sharp, N.J., Kornegay, J.N., Van Camp, S.D., Herbstreith, M.H., Secore, S.L., Kettle, S., Hung, W.Y., Constantinou, C.D., Dykstra, M.J., and Roses, A.D. (1992). An error in dystrophin mRNA processing in golden retriever muscular dystrophy, an animal homologue of Duchenne muscular dystrophy. Genomics 13, 115–121.