Pituitary Dwarfism (HZ Dog)
Pituitary dwarfism is caused by changes of the pituitary gland. Growth slows down after 8-12 weeks, followed by a growth arrest and further health impairments of the dog.
The disease occurs in the German Shepherd Dog and similar breeds. The inheritance is autosomal recessive.
Symptoms
- Growth slows down after 8-12 weeks, followed by growth arrest
- Skin changes: thickened, scabby, crusty and sebaceous deposits
- Puppy coat is retained unusually long
- Dull and rough topcoat
- Hairless areas (alopecia)
- Hyperpigmented skin
General Information
- The pituitary gland produces six hormones. One of them, growth hormone (GH), is essential for growth.
- A change in the LHX3 gene causes the alteration of the pituitary gland and the disturbance of growth.
- Life expectancy is 4-5 years.
Breeds affected
German Shepherd Dog, White Swiss Shepherd Dog, Saarloos Wolfdog and others.
Test Information
This mutation test detects the deletion in intron 5 of the LHX3 gene.
Genotype and Lab Report
Inheritance: autosomal recessive
→ The disease only occurs if both alleles of the gene are affected by the mutation (hz/hz). Dogs that have only one allele with the causative mutation (N/hz) are clinically healthy carriers.
Genotypes:
N/N = genetically normal
The dog has no predisposition for HZ and therefore cannot pass it on to its offspring.
N/hz = a carrier
The dog is a clinically healthy carrier. The variation is passed on 50% to the offspring, which are also carriers.
hz/hz = affected
The variation is passed on 100% to the offspring (if the animal is able to reproduce at all). The offspring are carriers or affected.
Recommendations
- Carrier animals can be bred to normal animals (N/hz x N/N). Before breeding with the offspring, it should be tested whether they are normal or carriers.
- Mating two carrier animals (N/hz x N/hz) should be avoided because there is a 25% chance that the offspring will be affected.
- Affected animals (hz/hz) should be excluded from breeding.
Literature
Voorbij, A.M., van Steenbeek, F.G., Vos-Loohuis, M., Martens, E.E., Hanson-Nilsson, J.M., van Oost, B.A., Kooistra, H.S., Leegwater, P.A.: A contracted DNA repeat in LHX3 intron 5 is associated with aberrant splicing and pituitary dwarfism in German shepherd dogs.PLoS One 6:e27940, 2011. Pubmed reference: 22132174. DOI: 10.1371/journal.pone.0027940.
Further information is available at: Online Mendelian Inheritance in Animals.