Common Symptoms
Pituitary dwarfism is a congenital growth hormone deficiency affecting dogs. Pituitary glands of affected dogs fail to develop normally, resulting in a deficiency of multiple hormones associated with growth and development. Affected dogs are smaller than littermates by 2 to 3 months of age and never attain normal adult size. Aside from growth deficiencies, affected dogs also display a characteristic retention of their soft, wooly puppy coat and fail to grow primary guard hairs. Various skin abnormalities are common and include scaling, bacterial skin infections, and hyperpigmentation. By 3 to 5 years of age, affected dogs often display severe Alopecia of the trunk, neck, and limbs and suffer from other disease associated complications such as mental dullness and kidney disease. If untreated, affected dogs often die or are humanely euthanized by 5 years of age due to concerns about quality of life.
Testing Tips
Genetic testing of the LHX3 gene will reliably determine whether a dog is a genetic Carrier of pituitary dwarfism. Pituitary dwarfism is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the LHX3 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Voorbij AMWY, Leegwater PA, Kooistra HS. Pituitary Dwarfism in Saarloos and Czechoslovakian Wolfdogs is Associated with a Mutation in LHX3. J Vet Intern Med. Nov-Dec 2014;28(6):1770-4. doi: 10.1111/jvim.12448. Epub 2014 Oct 1.
[PubMed: 25273400]
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Voorbij AMWY, van Steenbeek FG, Vos-Loohuis M, Martens EECP, Hanson-Nilsson JM, van Oost BA, Kooistra HS, Leegwater PA. A contracted DNA repeat in LHX3 intron 5 is associated with aberrant splicing and pituitary dwarfism in German shepherd dogs. PLoS One. 2011; 6(11):e27940. doi:10.1371/journal.pone.0027940.
[PubMed: 22132174]
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Voorbij, AMWY. Shedding light on canine pituitary dwarfism. (2015). https://dspace.library.uu.nl/handle/1874/318548
