Pituitary dwarfism or also known as DW is a disease caused by abnormal development of the pituitary gland, so the hormones secreted by it will be insufficient or null. Among the hormones affected is growth hormone. The thyroids are also affected with below normal function in terms of performance. Affected dogs, in addition to being small, could suffer from baldness, inflammation, joint dysfunction, slow learning, abnormal behavior and many other "side effects".
Most of the puppies totally affected by DW die during childbirth (90%), the rest will not survive the first days of life, since they do not secrete the necessary hormones.
Those puppies partially affected by DW, secrete a minimum necessary to survive, they will do so for a maximum of 4 or 5 years. These dogs can be treated hormonally, being able to reach 10 years of life thanks to this.
For its control, it is a priority to carry out tests before crossing the individual. A DNA test makes detection possible. This test can be performed at any age, including newborn puppies, through blood or saliva.
The different genotypes (results that can be obtained) are:
N/N: individual called “free”, does not carry or transmit the mutated gene (dw); healthy individual.
DW/N: individual called “carrier”, carries a mutated gene (dw), transmits the mutated gene to his descendants with a probability of 50%; healthy individual.
DW/DW: carries both mutated genes, they are supposed to be infertile, however, in the supposed case of being fertile, these dogs would transmit the mutated gene to their descendants with a 100% probability; sick individual.
The club allows the following combinations for breeding:
N/N + N/N, N/N + N/DW, (breeding with sick specimens would not be possible as they are sterile)
In all cases, one of the parents must be free, in this way it is ensured that DW/DW individuals will not be born, that is, sick. Unlike degenerative myelopathy where being DM/DM is a high risk factor for developing the disease, in pituitary dwarfism, DW/DW individuals are always sick.
Here we can see the growth stage of an affected dog and its development in adulthood: