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Inherited syndrome with craniofacial dysmorphism and skeletal and other anomalies. Frequently associated with respiratory failure in the neonatal period.

Multisynostotic Osteodysgenesis with Long Bone Fractures; Trapezoidocephaly-Synostosis Syndrome.

First description in 1975 by Ray M. Antley and David Bixler, two American physicians.

Inherited as an autosomal recessive genetic trait. A few cases may be sporadic or transmitted as an autosomal dominant trait. Parental consanguinity is a known risk factor.

The flavoprotein POR (cytochrome P-450 [oxido]reductase) is the electron donator for all microsomal P-450 enzymes. Mutations in this POR gene could be demonstrated in patients with Antley-Bixler syndrome. The lack or malfunction of POR may result in accumulation of drugs and environmental toxins usually metabolized by hepatic cytochrome P-450, which may result in levels high enough to cause teratogenicity. Fluconazole is one drug that has been implicated in the pathogenesis of Antley-Bixler syndrome. This genetic defect has been mapped to 7q.11.2. The role of a mutation in the FGF-2 gene, which initially was suspected to be the cause of this disorder, now seems less certain. Abnormalities of the steroid biogenesis have been reported and seem to be at least partly responsible for the genital anomalies found in female patients.

Based on clinical findings of trapezoidocephaly and multiple skeletal fusion. Craniofacial anomalies result in severe upper airway obstruction that can lead to death secondary to respiratory failure at birth or in the first weeks of life in approximately 50% of cases.

Multiple malformations predominately involve the head: severe midface hypoplasia, frontal bossing, craniosynostosis, brachycephaly, low-set dysplastic ears, small nose with low nasal bridge, anteverted nares, and choanal atresia are common. Acrocephaly, flat supraorbital ridges, proptosis, down-slanted palpebral fissures, hypertelorism, paresis of ocular muscles, cleft soft palate with bifid uvula, microstoma, and long philtrum are less common findings. Skeletal findings include narrowing of the rib cage, abnormal vertebrae, pelvic anomalies (narrow iliac wings), absent or abnormal (bowing) femora, radioulnar and radiohumeral synostosis, restricted joint mobility secondary to contractures, camptodactyly, arachnodactyly, talipes varus or valgus, and multiple fractures. Congenital fractures (in some cases multiple) have been described. Congenital cardiac defects (e.g., atrial septal defect), anomalies of the urinary tract (renal agenesis) and external female genitalia (vaginal atresia, hypoplastic labia majora, agglutinated labia minora), and imperforate anus may occur. Intellectual status can be normal, but variable degrees of mental retardation and hydrocephalus have been reported.

Evaluate the airway carefully (clinically, radiographically, eventually use fiberoptic examination). Check overall joint mobility (particularly neck mobility and mouth opening). Determine neurologic status and rule out cardiac anomalies (clinically, echocardiographically, electrocardiographically). Check renal function (creatinine, BUN).

Airway management (mask ventilation, direct laryngoscopy, tracheal intubation) can be difficult because of facial malformations, as reflected by high mortality in the first weeks of life secondary to respiratory complications. Choanal atresia may require emergency tracheostomy at birth. Maintenance of spontaneous ventilation and ...

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