Cyclic Neutropenia
Affected Genes: AP3B1
Inheritance: Autosomal Recessive
Variant(canFam6):
chr3:29903816: 1 bp insertion A
Breed: Collie
Old-Time Scotch Collie
Rough Collie
Scottish Collie
Smooth Collie
General Information: Cyclic Neutropenia (CN) is an inherited condition primarily affecting collies, where dogs experience periodic fluctuations in neutrophil levels, a type of white blood cell crucial for combating bacterial and fungal infections. These oscillations occur approximately every two weeks, with neutrophil counts varying from normal to nearly zero. Symptoms typically manifest during or immediately after periods of low neutrophil levels and include fever, diarrhea, inflamed lymph nodes, gingivitis, lameness, and mild bleeding episodes. Affected puppies may die within days of birth or show stunted growth, and despite medical care, most dogs succumb to liver or kidney failure before reaching two years of age.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog Unlikely Affected
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing of the AP3B1 gene can determine if a dog is a carrier of Cyclic Neutropenia (CN). CN is inherited in an Autosomal Recessive manner, meaning a dog must inherit two copies of the mutated gene (one from each parent) to develop the disease. Carrier dogs, possessing only one copy of the mutation, do not exhibit symptoms but can pass the gene to their offspring. Breeding two carriers together risks producing affected puppies, with each pup having a 25% chance of developing the disease and a 50% chance of being a carrier. Reliable genetic testing is essential for breeders to make informed decisions, avoid mating two carriers, and aim to eliminate this mutation from breeding lines, thereby reducing the occurrence of affected pups.
References:
Benson KF, Li FQ, Person RE, Albani D, Duan Z, Wechsler, Meade-White K, Williams K, Acland GM, Niemeyer G, Lothrop CD, Horwitz M. Mutations associated with neutropenia in dogs and humans disrupt intracellular transport of neutrophil elastase. Nat Genet. 2003 35(1):90-6.
Lothrop CD Jr, Coulson PA, Nolan HL, Cole B, Jones JB, Sanders WL. Cyclic hormonogenesis in gray collie dogs: interactions of hematopoietic and endocrine systems. Endocrinology 1987 120(3):1027-32.