Biallelic truncating variants in cause syngnathia in humans.

Background: Syngnathia is an ultrarare craniofacial malformation characterised by an inability to open the mouth due to congenital fusion of the upper and lower jaws. The genetic causes of isolated bony syngnathia are unknown.

Methods: We used whole exome and Sanger sequencing and microsatellite analysis in six patients (from four families) presenting with syngnathia.