Golden Retriever Muscular Dystrophy (GRMD) is a degenerative muscular disease caused by defect in protein dystrophin. The disease is progressive, causes movement disorders and often ends with death. Genetic defect is located on chromosome x, therefore the disease is more often expressed in males as only one affected allele is needed for development of the disease. Females develop the disease only if they inherit two affected alleles. The same genetic defect in humans causes Duchenne muscular dystrophy. Typical clinical signs are muscular weakness, impaired walking, swallowing difficulty, excessive drooling, breathing difficulty and exercise intolerance. Affected dogs show elevated levels of serum creatine kinase, degeneration and mineralization of hyaline myofibrils, muscular fibrosis with fat infiltrations and cardiomyopathy. GRMD is usually expressed around 8 weeks of age. Dogs with severe form of the disease may not live past the first few days of diagnosis while dogs with milder form of the disease can survive several years.
Inheritance: X-linked recessive- read more
Mutation: DMD gene
Genetic test: Disease or carrier can be identified by genetic testing at any age. The PCR method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs.
Disease control: Regarding to the presence of tested mutation animals are classified in three groups:
- Affected- all males who carry a mutation and females with a mutation on both alleles
- Carrier- only females who carry a mutation on one allele
- Clear- mutation is not present, normal genotype
For each group different breeding strategies should be followed. Breeding of affected and carrier animals should be avoided. All males who carry a mutation are affected. In order to eradicate the disease it is crucial to detect female carriers.
Affected breeds: Golden Retriever
Sample: EDTA whole blood (1.0 ml) or buccal swabs. Detailed information about sampling can be found here.