Otocephaly-dysgnathia complex is characterized by mandibular hypo- or aplasia, ear abnormalities, microstomia, and microglossia. Mutations in the orthodenticle homeobox 2 (OTX2) and paired related homeobox 1 (PRRX1) genes have recently been identified in some cases. We screened 4 otocephalic cases for these 2 genes and identified OTX2 mutations in 2 of them, thus confirming OTX2 is implicated in otocephaly. No PRRX1 mutation was identified. Interestingly, ocular involvement is not a constant feature in otocephalic cases with an OTX2 mutation. In one case, the mutation was inherited from a microphthalmic mother. The mechanism underlying this intrafamilial phenotypic variability remains unclear, but other genetic factors are likely to be necessary for the manifestation of the otocephalic phenotype.
Keywords: Agnathia; Microphthalmia; OTX2; Otocephaly; PRRX1.