Antley-Bixler syndrome (Q93976)

Antley-Bixler syndrome is a very rare disorder characterised by craniosynostosis with midface hypoplasia, radiohumeral synostosis, femoral bowing and joint contractures. Two genetically distinct forms are observed: type 1 Antley-Bixler syndrome is associated with heterozygous mutations in the FGFR2 gene (10q26) without impairment of steroidogenesis, whereas type 2 Antley-Bixler is associated with homozygous mutations in the POR gene (7q11.2), encoding cytochrome P450 oxidoreductase (POR), which plays a direct role in steroidogenesis. Type 2 Antley-Bixler can thus be accompanied by sexual ambiguity.