Microgenia

Microgenia is the medical term for an unusually small or deformed chin.

The contrasting condition, an enlarged chin, is called "macrogenia".

There are seven different chin deformities:
 * Class I: Macrogenia (chin excess)
 * Class II: Microgenia (chin deficiency)
 * Class III: Combined excesses and deficiencies
 * Class IV: Assymmetric deformity
 * Class V: Witch's chin
 * Class VI: Pseudomacrogenia
 * Class VII: Pseudoretrogenia

Class II microgenia is the most commonly encountered chin deformity, followed by class II macrogenia.

Causes
Can occur in anyone, but is often a sign of Down syndrome.