Hemifacial microsomia

Hemifacial microsomia (HFM) is a congenital disorder that affects the development of the lower half of the face, most commonly the ears, the mouth and the mandible. It usually occurs on one side of the face, but both sides are sometimes affected. [Source: Wikipedia ]

OrphaNet reference
Hemifacial microsomia 
May Cause
Facial asymmetry