Skeletal atavism (SA)
Skeletal atavism is a type of dwarfism found in Shetland ponies and Miniatures. Foals born with this type of dwarfism have short, twisted legs. There is a wide range of severity. Some of the severe cases seen in Australia have been unable to stand due to abnormal joint angles and reduced range of motion in the front legs or hind legs.
Anecdotal reports suggest that foot trimming can be used to reduce angular deformities in less severe cases. It's not clear whether this works in the long term as well as the short term.
The test for skeletal atavism is not patented in Australia. Unfortunately, due to the nature of the SA mutations we are currently unable to test for it in our laboratory. Any testing submitted to us will be forwarded to UC Davis.
Gene or region and technical reference
Gene: pseudo autosomal region (causative). Reference: Rafati et al. (2016)
n. Test developed using unknown.
del1. Test developed using unknown.
del2. Test developed using unknown.
This illustration of SA shows a relatively mild case.