Deformity

A deformity, dysmorphism, or dysmorphic feature is a major difference in the shape of the body a body part, or a body organ (internal or external) compared to the average shape for the part in question.

Deformity may arise from numerous causes:
 * A genetic mutation
 * Damage to the fetus or uterus
 * Complications at birth
 * A growth or hormone disorder
 * Reconstructive surgery following a severe injury e.g. burn injury.
 * Arthritis and other rheumatoid disorders

Irish Mythology includes the Fomorians, who are almost without exception described as being deformed, possessing only one of what most have two of (eyes, arms, legs, etc.) or having larger than normal limbs. Other mythological creatures may have been created due to a deformative syndrome also, for instance, descriptions of mermaids may be related to the symptoms of sirenomelia.

Deformity can occur in non-humans, as well. Frogs can be mutated due to Ribeiroia (Trematoda) infection.

It is important to note that in many cases, deformed individuals do not survive. For example, in many cases in which a major deformity is present at birth, it is the result of an underlying condition severe enough that the baby does not survive very long. Or, in cases in which an individual becomes deformed due to an event, the event may kill the individual. In some societies, defective babies are abandoned at birth: some are saved by the "kindness of strangers"(See John Boswell).