A rare congenital condition characterized by mandibular hypoplasia or agnathia (absence of mandible), mispositioning of the ear auricles (melotia) and/or abnormal fusion of the earlobes (synotia), and MICROSTOMIA with oroglossal hypoplasia or aglossia. It occurs frequently with HOLOPROSENCEPHALY; skeletal, genitourinary, and cardiovascular anomalies, and SITUS INVERSUS may also be present. The disorder is almost always lethal and is caused by mutations in the paired related homeobox 1 gene (PRRX1) OMIM: 202650
