A rare, non-syndromic, limb reduction defect characterized by the partial or complete absence of all four limbs. Sometimes, other malformations may be associated.

Missing or malformed long bones of the extremities with the distal parts (such as hands and/or feet) connected to the variably shortened or even absent extremity, leading to a flipper-like appearance, as opposed to other forms of limb malformations were either the hole limb is missing (such as amelia), or the distal part of a limb is absent (peromelia).