Arabians, pure and part-bred
Friesians, pure and part-bred
Fell Ponies, Dale Ponies and Gypsy horses, pure and part-bred
Quarter horses and related breeds, pure and part-bred
Saddlebred and related breeds, pure and part-bred
Coat colour tests
The typical features of horses affected by Friesian dwarfism are short legs, ribs that narrow markedly from a broad chest and flexor tendon laxity. Dwarf Friesian horses can be down on their bumpers at maturity, with some reports that it can worsen rather than improve with age.
Our test is for a mutation in the B4GALT7 gene identified in Friesian horses that severely reduces the production of galactosyl transferase I (Leegwater et al., 2016, DOI 10.1186/s12864-016-3186-0).
Friesian dwarfism is an autosomal recessive disorder. Autosomal disorders are equally likely to affect male or female horses, while "recessive" means that a horse needs to inherit the mutation from both its sire and its dam to be affected. Horses that have inherited the Friesian dwarfism mutation from just one parent are called Friesian dwarfism carriers, and do not usually have physical signs of this disorder.
We regularly identify Friesian dwarfism carriers in Australia. However since we are often testing foals from a known carrier parent we are not sure of the true prevalence in our population.