Congenital malformation characterized by MICROGNATHIA or retrognathia; GLOSSOPTOSIS and cleft palate. The mandibular abnormalities often result in difficulties in sucking and swallowing. The syndrome may be isolated or associated with other syndromes (e.g., andersen syndrome; campomelic dysplasia). Developmental mis-expression of sox9 transcription factor gene on chromosome 17q and its surrounding region is associated with the syndrome.