Human Phenotype Ontology entry HP_0000278 (Retrognathia) can be described as follows. An abnormality in which the mandible is mislocalised posteriorly. Also known as: Lower jaw retrognathia, Lower jaw retrusion, Mandibular retrognathia, Mandibular retrusion, Receding chin, Receding lower jaw, Receding mandible, Retrognathia of lower jaw.