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A rare genetic disorder affecting skeletal development

Antley–Bixler syndrome is a rare genetic disorder characterized by craniosynostosis, skeletal dysplasia, and other systemic abnormalities. It is named after Raymond Antley and David Bixler, who first described the condition in 1975. The syndrome is associated with mutations in the FGFR2 and POR genes, leading to abnormal development of bones and other tissues.

Presentation

Individuals with Antley–Bixler syndrome typically present with a variety of congenital anomalies. The most prominent features include:

• Craniosynostosis: Premature fusion of the cranial sutures, leading to an abnormal head shape and potential intracranial pressure issues.
• Midface hypoplasia: Underdevelopment of the midfacial region, which can result in respiratory difficulties and feeding problems.
• Radiohumeral synostosis: Fusion of the radius and humerus bones, limiting elbow movement.
• Femoral bowing: Curvature of the femur, which can affect mobility.
• Joint contractures: Stiffness and limited range of motion in various joints.

Additional features may include genital anomalies, renal malformations, and cardiac defects.

Genetics

Antley–Bixler syndrome can be inherited in an autosomal recessive or autosomal dominant manner, depending on the underlying genetic mutation. The autosomal recessive form is often associated with mutations in the POR gene, which is involved in steroidogenesis and drug metabolism. The autosomal dominant form is linked to mutations in the FGFR2 gene, which plays a critical role in bone development.

Diagnosis

Diagnosis of Antley–Bixler syndrome is based on clinical evaluation, radiographic imaging, and genetic testing. X-rays can reveal characteristic skeletal abnormalities, while genetic testing can confirm mutations in the FGFR2 or POR genes.

Management

Management of Antley–Bixler syndrome is multidisciplinary, involving pediatricians, geneticists, orthopedic surgeons, and other specialists. Treatment focuses on addressing specific symptoms and may include:

• Surgical intervention for craniosynostosis and other skeletal deformities.
• Physical therapy to improve joint mobility and muscle strength.
• Respiratory support for individuals with airway obstruction.
• Hormonal therapy for those with steroidogenesis defects.

Prognosis

The prognosis for individuals with Antley–Bixler syndrome varies depending on the severity of the condition and the presence of associated anomalies. Early intervention and comprehensive management can improve quality of life and functional outcomes.

Related pages

• Craniosynostosis
• Skeletal dysplasia
• Genetic disorder
• FGFR2

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  Autosomal recessive inheritance pattern