Neonatal Cerebellar Cortical Degeneration
Neonatal cerebellar cortical degeneration (NCCD) is a hereditary disease that can affect Beagles puppies. Affected puppies start showing clinical signs around three weeks of age. They are slower and less coordinated than the littermates, fall more often and are unable to regulate a normal gait. This disease has minimal progression but currently there is no cure. The clinical signs are due to damage in their cerebellum, which is the part of the nervous system that controls the movement and the equilibrium.
In 2012 veterinary neurologists and scientists from the Kennel Club Genetics Centre at the Animal Health Trust identified the mutation for NCCD in the Beagle and made a DNA test available. The mutation is recessive, meaning only dogs that inherit two copies of the mutation are affected by NCCD; dogs with one copy (carriers) or no copies (clears) cannot develop NCCD although carriers will pass the mutation onto about half of their puppies if they reproduce.
Beagle owners who use the NCCD DNA test will be sent results identifying their dog as belonging to one of three categories. In all cases the terms ‘normal’ and ‘mutation’ refer to the position in the DNA where the NCCD mutation is located; it is not possible to learn anything about any other region of DNA from the NCCD DNA test.
CLEAR: these dogs have two normal copies of DNA and will not develop NCCD as a result of the NCCD mutation. Please note; we cannot exclude the formal possibility they could develop a clinically similar but genetically different disorder due to other mutations that are not detected by this test.
CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. These dogs will not develop NCCD themselves as a result of the NCCD mutation but they will pass the mutation on to approximately 50% of their offspring.Please note; we cannot exclude the formal possibility they could develop a clinically similar but genetically different disorder due to other mutations that are not detected by this test.
GENETICALLY AFFECTED: these dogs have two copies of the NCCD mutation and will be affected with NCCD.
The NCCD mutation is recessive so both clear and carrier dogs can be safely bred with, provided at least one of the mating pair is clear of the mutation. Carriers should always be included in the first one to two generations that follow the launch of a DNA test for a recessive mutation, regardless of the frequency of the mutation, to give breeders the opportunity to capture desirable traits, such as breed type and temperament, before they start to select for dogs that are clear of the mutation. Elimination of the NCCD mutation from the breed should be the long-term goal, now that a DNA test for that mutation is available. But, providing all breeding dogs are tested for the mutation prior to mating, Beagle breeders should take their time and ensure that desirable traits are not eliminated along with the disease mutation and that the genetic diversity of the breed is not reduced.
Further details can be found here.