Narcolepsy (canarc1 Labrador)

• Fatigue during the day
• Cataplexy → sudden, temporary flaccid paralysis of individual muscle groups (partial paralysis), or of the entire skeletal musculature (total paralysis).
• Partial paralysis: e.g. weakness of the hind legs leading to sudden sitting down
• Total paralysis: falling down with subsequent inability to move (similar to consciousness)

• The first symptoms occur in the first 6 months of life.
• Triggers are excitatory events (feeding, playing).
• The paralysis lasts from a few seconds to five minutes.
• The episode ends when the dog is touched or spoken to loudly and is completely reversible.
• The severity of the disease is defined by the frequency of cataplectic episodes within a certain period of time.

This mutation test detects a change in a single base pair (Int6G5A), which in turn leads to a deletion of exon 6 in the HCRTR2 gene.

Test in Shop

Also in the Labrador Retriever B package (DRC P3)

Inheritance: autosomal recessive

→ The disease only occurs if both alleles of the gene are affected by the mutation (narc/narc). Dogs that have only one allele with the causative mutation (N/narc) are clinically healthy carriers.

Genotypes:

N/N = genetically normal

The dog has no variants for narcolepsy and therefore cannot pass it on to its offspring.

N/narc = a carrier

The dog is a clinically healthy carrier. The variant is passed on 50% to the offspring, who are also carriers.

narc/narc = affected

The variation is passed on 100% to the offspring. The offspring are carriers or affected.

• Carrier animals can be bred to normal animals (N/narc x N/N). Before using the offspring in breeding, it should be tested whether they are normal or carriers.
• Mating two carrier animals (N/narc x N/narc) should be avoided because there is a 25% chance that the offspring will be affected.
• Affected animals (narc/narc) should be excluded from breeding.

Lin, L., Faraco, J., Li, R., Kadotani, H., Rogers, W., Lin, X.Y., Qiu, X.H., de, Jong, P.J., Nishino, S., Mignot, E.: The sleep disorder canine narcolepsy is caused by a mutation in the hypocretin (orexin) receptor 2 gene Cell 98:365-376, 1999. Pubmed reference: 10458611.

Hungs, M., Fan, J., Lin, L., Lin, X.Y., Maki, R.A., Mignot, E.: Identification and functional analysis of mutations in the Hypocretin (Orexin) genes of narcoleptic canines Genome Research 11:531-539, 2001. Pubmed reference: 11282968. DOI: 10.1101/gr.161001.

Further information is available at: Online Mendelian Inheritance in Animals.