Pituitary Dwarfism (Discovered in the Karelian Bear Dog)

Pituitary Dwarfism is a hormone disorder characterized by stunted growth and coat abnormalities, such as a retained puppy coat or excessive coat thinning. The associated genetic variant has been identified in the Karelian Bear Dog.

Key Signs

Retained puppy coat, Severe hair loss, Thin skin, Hyperpigmented skin, Stunted growth, Secondary endocrine disorder possible, Secondary organ dysfunction possible

Age of Onset

0 to 2 yrs

Juvenile onset


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with Pituitary Dwarfism

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about Pituitary Dwarfism

Pituitary Dwarfism is an endocrine disorder caused by a pituitary gland abnormality that results in growth hormone deficiency. Signs include stunted growth resulting in a proportionately small stature, excessively thin or hyperpigmented skin, and coat abnormalities, such as a retained puppy coat or an otherwise normal appearing coat prior to significant hair loss around the age of 2 to 3 years. The disorder is usually identified in puppies between the ages of 2 to 5 months old when it is noticed that the affected puppy is not growing at a proper rate, making them noticeably smaller than their littermates, and they are not replacing the puppy coat with a normal adult coat. Affected puppies may also seem mentally dull in comparison to their littermates. Dogs diagnosed with Pituitary Dwarfism are often sterile due to underdeveloped reproductive organs. Additionally, kidney disease or secondary endocrine disorders, such as hypothyroidism or hypoadrenocorticism, may develop due to underdeveloped organs or underactive glandular tissue. Affected dogs tend to experience a shortened lifespan and, without treatment, their life expectancy is approximately 3 to 5 years.

Treating Pituitary Dwarfism involves lifelong supplementation of the missing growth hormone or progestins and treatment for any secondary hormonal disorders, like hypothyroidism. Due to potential side effects of treatment, routine monitoring and periodic adjustments may be necessary. Quality of life tends to improve significantly in affected dogs receiving treatment, and prognosis also improves with the average lifespan being roughly 5 to 7 years.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disorder is autosomal recessive, meaning two copies of the variant are needed for a dog to be at an elevated risk for being diagnosed with the condition. A carrier dog with one copy of the Pituitary Dwarfism (Discovered in the Karelian Bear Dog) variant can be safely bred with a clear dog with no copies of the Pituitary Dwarfism (Discovered in the Karelian Bear Dog) variant. About half of the puppies will have one copy (carriers) and half will have no copies of the variant. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disorder signs similar to the ones associated with this Pituitary Dwarfism variant could develop due to a different genetic or clinical cause.

Technical Details

Gene POU1F1
Variant C>A
Chromosome 31
Coordinate 784,534

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Kyöstilä, K., Niskanen, J.E., Arumilli, M., Donner, J., Hytönen, M.K., Lohi, H. (2021). Intronic variant in POU1F1 associated with canine pituitary dwarfism. Hum Genet, 140 (11), 1553-1562. View the article