Quick Summary
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Phenotype: Affected dogs show episodes of low neutrophil counts (neutropenia), happening approximately every two weeks, that are followed by an increase in the number of neutrophils (neutrophilia) and immature red blood cells (reticulocytosis), and a decrease in platelet count (thrombocytopenia). Some affected puppies die within the first few weeks after birth. Those that survive typically show recurrent bacterial infections, bleeding, stunted growth and experience a shortened life span. It is not uncommon for affected dogs to also have color dilution and eye lesions.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, CN = Cyclic Neutropenia
Breeds appropriate for testing: Collie, Old-Time Scotch Collie, Rough Collie, Scottish Collie, Smooth Collie
Explanation of results:
• Dogs with N/N genotype will not have this inherited form of cyclic neutropenia and cannot transmit this allele to their offspring.
• Dogs with N/CN genotype will not be affected by this inherited form of cyclic neutropenia but are carriers. They may transmit this allele to 50% of their offspring. Matings between two carriers are predicted to produce 25% of affected puppies.
• Dogs with CN/CN genotype will likely develop this form of cyclic neutropenia and will transmit this allele to all of their offspring.
Sample Collection
Dog DNA tests are carried out using cells brushed from your dog's cheeks and gums. The preferred cytology brushes are sent to you by mail, or you may provide your own brushes. For accepted alternative brushes, click here
We recommend waiting until puppies are at least three weeks old before testing.
Step-By-Step:
- Make sure the dog has not had anything to eat or drink for at least 1 hour prior to collecting sample.
- When swabbing puppies, isolate each puppy from the mother, littermates and any shared toys for 1 hour prior to swabbing. Puppies should not have nursed or eaten for 1 hour prior to collecting sample.
- If collecting samples from more than one dog, make sure to sample one dog at a time and wash your hands before swabbing another dog.
- Label brush sleeve with name or ID of dog to be sampled.
- Open brush sleeve by arrow and remove one brush by its handle.
- Place bristle head between the dog’s gums and cheek and press lightly on the outside of the cheek while rubbing or rotating the brush back and forth for 15 seconds.
- Wave the brush in the air for 20 seconds to air dry.
- Insert brush back into sleeve.
- Repeat steps 5 - 8 for each unused brush in sleeve on a fresh area of cheek and gums. Make sure to use and return all brushes sent by the VGL. In most cases, it will be 3 brushes per dog. If using interdental gum brushes, please note that the VGL requires 4 brushes per dog and only moderate or wide interdental gum brushes are accepted.
- Do not seal brushes in sleeve.
- Place all samples in an envelope and return to the address provided.
ATTENTION:
- Do not collect saliva/drool – the key to obtaining a good sample is getting cheek cells on the swab
- Do not rub swab on the dog’s tongue or teeth – this will result in poor quality sample
- Do not collect a sample from a puppy that has recently nursed – the mother’s genetic material can rub off on the puppy’s mouth and contaminate the sample
Cyclic neutropenia, also known as Gray Collie Syndrome, is a heritable disorder that affects Collies and affected puppies often have hypopigmented (dilute) coats. The condition results in episodes of abnormally low numbers of neutrophils, a specific type of white blood cell that is responsible for fighting bacterial infections.
Some affected puppies die within the first few weeks after birth. Those that survive typically show recurrent bacterial infections, bleeding, stunted growth and experience a shortened life span. It is not uncommon for affected dogs to also have eye lesions.
Diagnosis is often made after blood work shows episodes of low neutrophil counts (neutropenia), happening approximately every two weeks, that are followed by an increase in the number of neutrophils (neutrophilia) and immature red blood cells (reticulocytosis), and a decrease in platelet count (thrombocytopenia).
Cyclic neutropenia is caused by a 1 base pair insertion in the AP3B1 gene that results in a frameshift and premature termination of the protein. The condition is inherited in an autosomal recessive manner, meaning that dogs must have two copies of the disease allele to be affected. Dogs with one copy of the disease allele are normal but can pass on the disease allele to their puppies.
Testing recommendations: Testing for cyclic neutropenia assists owners and breeders in identifying affected and carrier dogs. Dogs with one copy of the CN allele are normal but are carriers. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing dogs affected by this blood disorder.
