Primary Hyperparathyroidism in Keeshond Dogs: Causes & Testing

Primary hyperparathyroidism (PHPT) is a genetically inherited condition affecting dogs, particularly the Keeshond breed, caused by abnormal overproduction of parathyroid hormone by the parathyroid glands. These tiny glands, close to but distinct from the thyroid glands in the neck, normally regulate blood calcium and phosphorus balance.

In PHPT, excess parathyroid hormone causes high blood calcium levels (hypercalcaemia), which can affect various body systems and lead to serious health problems, especially in older dogs. Unlike the thyroid hormone, parathyroid hormone controls calcium release from bones and calcium absorption into the bloodstream.

Understanding Primary Hyperparathyroidism in Dogs

There are two forms of hyperparathyroidism in dogs: primary and secondary. Primary hyperparathyroidism is hereditary and occurs when one or both parathyroid glands secrete too much hormone, sometimes caused by tumours or gland enlargement (hyperplasia). Secondary hyperparathyroidism is usually due to dietary calcium deficiency and is not inherited.

In Keeshonds, primary hyperparathyroidism is especially prevalent, reflecting a strong genetic predisposition. Notably, the breed shows a very high incidence compared to other dogs in the UK.

Genetics and Heredity of PHPT in Keeshonds

PHPT in Keeshonds follows an autosomal dominant inheritance pattern. This means that a dog only needs to inherit one copy of the mutated gene from one parent to be at risk. Dogs with one copy of this gene have approximately a 50% chance of developing the condition.

If both parents carry the mutation, the risk for their puppies increases further, and litters may have a mix of affected and unaffected puppies. This dominant mode of inheritance means the condition could spread rapidly through the breed without careful management.

Interestingly, while PHPT in humans involves mutations in genes like MEN1 or RET, the specific mutation responsible in Keeshonds differs and has not yet been identified, though a genetic marker linked to PHPT has been discovered for testing.

Clinical Signs and Diagnosis

PHPT often presents in middle-aged to older Keeshond dogs. Early signs can be subtle, such as increased thirst and urination, lethargy, and decreased appetite. Left untreated, high calcium levels can lead to complications like kidney damage.

Diagnosis relies on blood tests showing elevated calcium and parathyroid hormone levels. Sometimes, the condition is found incidentally during routine health checks.

Importance of Genetic Testing and Responsible Breeding

Genetic testing plays a crucial role in managing PHPT in Keeshonds. A DNA test can identify dogs carrying the mutation. It is strongly recommended that carriers are not used for breeding to reduce the spread of the condition within the breed.

Breeders should work closely with veterinary geneticists and use reputable laboratories for testing. This responsible approach helps improve breed health and welfare in the long term.

How to Get Your Keeshond Tested

Owners of Keeshond dogs, and those with Keeshond ancestry, should consider genetic testing to know their dog's status. The test requires only a simple DNA sample, often a cheek swab or blood.

Visit The Kennel Club’s detailed page for a list of accredited laboratories offering the PHPT test to ensure you choose a reliable provider and obtain accurate results.

Summary and Next Steps

Primary hyperparathyroidism in Keeshond dogs is a serious but manageable hereditary condition caused by excessive secretion of parathyroid hormone leading to raised blood calcium. Its autosomal dominant inheritance means it can spread quickly if unchecked.

Genetic testing is the key tool available today to identify carriers and prevent breeding affected dogs. Early diagnosis can improve health outcomes by allowing timely treatment interventions.

For Keeshond owners and breeders, staying informed, testing breeding stock, and promoting responsible breeding practices help protect the health and future of this beautiful breed.