Complement 3 Deficiency

General Information: Complement 3 Deficiency is an inherited immune system disorder, primarily seen in Brittany dogs, caused by a lack of the protein complement component 3 (C3), which is crucial for preventing bacterial infections. Affected dogs often present with symptoms in early life, including recurrent bacterial infections such as pneumonia, urinary tract infections, and uterine infections. This condition also predisposes dogs to early-onset kidney disease, which can progress to chronic kidney failure and ultimately lead to death. Symptoms include frequent infections, lethargy, and signs of kidney dysfunction. Early diagnosis and management are essential to mitigate the risk of severe health complications in affected dogs.

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 C3 gene can identify whether a dog is a carrier of Complement 3 Deficiency (C3D), an autosomal recessive disorder. Dogs must inherit two copies of the mutated gene, one from each parent, to develop the disease. Carrier dogs, which possess only one copy of the mutation, typically do not show symptoms but can pass the mutation to their offspring. Breeding two carriers together increases the risk of producing affected puppies, with each pup having a 25% chance of inheriting the disease and a 50% chance of being a carrier. Reliable genetic testing is crucial for informed breeding practices to prevent the birth of affected puppies. To eliminate this mutation from breeding lines and reduce the risk of producing affected pups, it is recommended to avoid breeding two known carriers together. Dogs without the mutation do not have an increased risk of having affected offspring, ensuring a healthier lineage free from C3D.