Denouement and Discussion
Antley-Bixler Syndrome
Manifestations
Major manifestations include craniosynostosis, a characteristic facial appearance, choanal atresia/stenosis, radiohumeral synostosis, bowing of femurs with fractures, and multiple joint contractures.
Craniofacial abnormalities consist of brachycephaly secondary to craniosynostosis of the coronal and lambdoidal sutures; large anterior fontanelle; and a face characterized by frontal bossing, flat facies, severe midface hypoplasia, proptosis, flattened nasal bridge, pear-shaped nose, choanal stenosis/atresia, long philtrum, and small, dysplastic ears.
Skeletal abnormalities include radiohumeral synostosis, anterior bowing of femurs with neonatal fractures, medial bowing of ulnas, narrow iliac wings, arachnodactyly with distal tapering of digits, camptodactyly, and scoliosis. Other occasional abnormalities are hydrocephalus, atrial septal defects, vaginal atresia, renal defects, multiple hemangiomata, and preauricular tags. Auditory dysfunction may also occur.
In most reported cases, prenatal and postnatal growth have been normal. Respiratory compromise generally occurs secondary to upper-airway obstruction (choanal stenosis/atresia occurs in about one half of affected individuals) and may vary from nasal congestion to apnea leading to death. Some patients have died in infancy of unexplained causes. Patients followed up beyond age 1 year have been ambulatory. Intelligence varies from normal to mild retardation.
Genetics
Antley-Bixler syndrome occurs sporadically, but has been reported in siblings and children of consanguineous parents. Therefore, inheritance is most likely autosomal recessive with a 25% recurrence risk for the condition in subsequent children from the same parents.
Treatment
Treatment consists of management of the orthopedic abnormalities, including the multiple joint contractures, through physical therapy, casting, and/or surgery. Surgery may also be necessary to alleviate upper-airway obstruction and to correct the craniosynostosis. Hearing, cardiac, and renal evaluations are also indicated. Genetic counseling and prenatal diagnosis should be discussed with the family.
Figs 1 and 2.
3-week-old newborn with brachycephaly; prominent forehead; flat face; low-set, dysplastic ears; flattened nasal bridge; pear-shaped nose; severe, midface hypoplasia; proptosis; flexed position of elbow; and camptodactyly.
Fig 3.
Radiohumeral synostosis.
Fig 4.
Bowing of the femur.
References
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