Skeletal Atavism Dwarfism

Genetic testing possible at capilet genetics, sweden - have a closer look at genetic testing tab.

About it

Skeletal Atavism is a genetic disease which interupts the developmental growth in foals limbs.


Two mutation causing this defect are identified and can be tested now.


Skeletal Atavism is caused by two mutant alleles. Affected foals are Del1/Del1, Del1/Del2, Del2/Del2. Carriers are N/Del1, N/Del2. The genetic testing will give result which mutation your horse carries, if it is a carrier, a affected horse/dwarf or healthy N/N.


You can avoid giving birth to affected foals by responsible breeding. Do not cross carriers!


Should your foal show more abnormalies than abnormal development in the limbs a combination with ACAN-dwarfism is possible.


Affected Breeds: Shetland Pony, American Miniature Horse

Pics on a yearling Shetland Pony: Note the outward bending of the leg and the short distance between hind knee and hock as well as front knee and elbow.

This heritable disease causes skeletal deformations in limbs and impairs the movements.

Main features

  • The defect is an abnormal development of the legs, which can occur in both front and hind legs
  • Ulna (next to the radius) and fibula (next to tibia) is developed throughout their full length. Normally, the distal part of these bones should fuse to the radius and tibia respectively as the horse grows


  • This leads to a disturbed growth of adjacent bones, severe angle anomalies and deformation of the front knee and hock
  • Typical characteristics of horses with Skeletal atavism are short legs, a low rectangular shape body, narrow at knees (knock-kneed), cow hocked, clubfoot, toe out and impaired movements
  • The pattern of movement become gradually worse as the foal is growing and in most cases, the horse has to be euthanized within six months

Gallery (These pics are showing types of skeletal atavism through all colours in Miniature Breeds)

I appriciate each Pic which I can use for this homepage. If you want to send me a pic an your skeletal atavism dwarf please send them to Thanks a lot!


Mrs. Marleen Binder

RIP: Daisy, skeletal atavism dwarf, 2006
RIP: Daisy, skeletal atavism dwarf, 2006