Homozygotes show reduction of the postaxial digits of all four limbs in varying degrees of severity. There may also be reduction or absence of the ulna or fibula. The tail may be shortened and kinked, the last rib is reduced in size or absent, and the ribs and sternebrae may show fusions. The spleen may be reduced in size and deformed, and there may be horseshoe kidney or the kidneys may be cystic or absent (J:30743). Few homozygotes live beyond 1 month. Survivors are small and do not breed.