Dwarfism
It is present in several breeds such as the Frisian or the Shetland and therefore also in the breeds of Miniature Horses. Dwarfism is generally due to inbreeding and is characterized by multiple deformations, both external and internal. It is a degenerative genetic disease, affected individuals have a very reduced life expectancy.
Today, two genes are known and can be tested in order to lead informed marriages.
ACAN (D1 to D4)
These are the 4 main mutations of Dwarfism that we meet in the Miniature Horse. Each type having a different form and consequences on the affected subjects. Dwarfism is generally characterized by horses exhibiting hydrocephalus , deviated limbs, prognathism , a deformation of the spine, abnormally small and disproportionate size.
Skeletal Atavism (Del1 & Del2)
Form of Dwarfism which is characterized by an imbalance in the growth of the limbs . Rarer than ACAN, it is nonetheless important to test. It is considered that 12% of the global herd (healthy and / or affected carriers) is affected by this form.
Two horses that are healthy carriers of one of its genes have a 25% risk of giving birth to an affected foal. It is therefore essential for breeders and owners to know the status of their horses (free or carrier) before putting them for breeding. Therefore, it is up to everyone to make their choices with full knowledge of the facts.
Let us also remember that a carrier horse is not affected by the disease , it carries the gene in a single copy without the consequences associated with it when it is present in two copies. The priority today is therefore to test and to have total transparency on the results of these tests.
Removing the horses carrying ACAN or SA is utopian and would lead to an impoverishment of the breed: disappearance of certain lines, increase in consanguinity. Particularly in France, in view of the current population. Make no mistake, many miniature horses are healthy carriers of ACAN or AS, or both.
A responsible breeder is able to manage his marriages according to the results of the tests, so as to obtain only free products or healthy carriers.