Antley-Bixler syndrome

Antley-Bixler syndrome


The Antley-Bixler syndrome is characterised by craniosynostosis, radiohumeral synostosis and femoral bowing. Most infants die in the first months of life from respiratory complications. Mode of inheritance: Autosomal recessive Type: usually lethal in infancy Synonyms: multisynostotic osteodysgenesis; short-limbed craniosynostotic form of campomelic dysplasia, trapezoidocephaly multiple synostosis syndrome. 


The craniosynostosis involves the lambdoid and coronal sutures, there is midface hypoplasia and low set ears with an abnormal helix. The head is brachycephalic and the face is flat with a depressed nasal bridge and frontal bossing. Other features include antigonial notching of the mandible, choanal atresia and external auditory canal atresia. The chest is narrow with slender ribs. The femurs are bowed, and there is fixed flexion at the elbow as a result of humeroradial synostosis. The metaphyses of these two bones are fused, and there is absence of the intervening cartilaginous epiphyses. Multiple joint contractures can be frequently seen. Bowing of the ulna, campodactyly and clubfoot are occasionally present. Some cases display long bone fractures. There may be associated urogenital and cardiac anomalies.

Differential Diagnosis

Acrocephalosyndactyly (Apert syndrome) lacks femoral bowing and humeroradial synostosis. Although partial cutaneous syndactyly can occasionally be seen in Antley-Bixler syndrome, extensive cutaneous and osseous syndactyly is typical of Apert syndrome. In Campomelic dysplasia there is no cranial or humeroradial synostosis, the tibia is frequently angulated and there is hypoplasia of the cervical vertebral bodies. Thanatophoric dysplasia type II can be differentiated on the basis of platyspondyly and micromelia.

Sonographic Features

Craniosynostosis: light-bulb appearance of the skull with increased biparietal diameter and decreased anteroposterior diameter (brachycephalic)

Abnormal profile with a flat face, depressed nasal bridge and frontal bossing

Bowed femur

Occasional long bone fractures

Humeroradial synostosis: limitation of elbow movement, with fixed flexion deformity

Associated Syndromes


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