Testing of dogs: Hypomyelination of the central nervous system
Related tests
- Combination Weimaraner DM (SOD1A) + HUU + Hypomyelination of the central nervous system + coat length + Dystonia-ataxia syndrome
Hypomyelination of the central nervous system in Weimaraners
Myelin is a lipoprotein sheath that surrounds the axons of nerve cells, which in the central nervous system is formed by specialized cells - oligodendrocytes. Myelin performs a protective function and has a great influence on the speed of nerve impulse propagation. In hypomyelination, this sheath is thinner or completely absent, the impulses between nerves are lost and the functionality of nerves and corresponding muscles is impaired. Symptoms include difficulty walking, poor coordination of movements, tremor.
In Weimaraner breed, the disease is caused by mutation c.1078del in the gene encoding the FNIP2 protein expressed in both neurons and oligodendrocytes. This mutation causes expression of truncated protein which causes abnormal development or function of neurons and oligodendrocytes.
The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.
The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.
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References:
Pemberton, T.J., Choi, S., Mayer, J.A., Li, F.Y., Gokey, N., Svaren, J., Safra, N., Bannasch, D.L., Sullivan, K., Breuhaus, B., Patel, P.I., Duncan, I.D.: A mutation in the canine gene encoding folliculin-interacting protein 2 (FNIP2) associated with a unique disruption in spinal cord myelination. Glia 62:39-51, 2014. Pubmed reference: 24272703.