Antley-Bixler syndrome (ABS), also known as trapezoidocephaly-synostosis syndrome, is a rare autosomal dominant or recessive condition characterized by craniosynostosis and extra-cranial synostoses. Mid-facial hypoplasia is also common.
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Epidemiology
It is a very rare condition with only 50 cases described in the global literature up to 2006 3.
Clinical presentation
- craniosynostosis
- limb synostoses e.g. radioulnar, radiohumeral
- mid-face hypoplasia - commonly associated with airway obstruction
- congenital heart disease
- renal maldevelopment e.g. agenesis
- POR mutation only: congenital adrenal hyperplasia and ambiguous genitalia
Pathology
Genetics
Mutations in two separate genes FGFR2 and POR have been found to produce the Antley-Bixler syndrome phenotype.
FGFR2 is inherited in an autosomal dominant manner and POR is in an autosomal recessive manner.
Treatment and prognosis
Neonatal mortality is up to 80%, with usual cause of death respiratory compromise. However as the child ages, prognosis improves.
History and etymology
First case was described by R Antley and D Bixler in 1975 3.