Antley–Bixler syndrome

Antley–Bixler syndrome
Classification and external resources
Specialty
ICD-10	Q87.0
OMIM	207410 201750
DiseasesDB	32831
Patient UK	Antley–Bixler syndrome
MeSH	D054882

Antley–Bixler syndrome, also called trapezoidocephaly-synostosis syndrome, is a rare, very severe autosomal recessive congenital disorder characterized by malformations and deformities affecting the majority of the skeleton and other areas of the body.

Presentation

Antley–Bixler syndrome presents itself at birth or prenatally. Features of the disorder include brachycephaly (flat forehead), craniosynostosis (complete skull-joint closure) of both coronal and lambdoid sutures, facial hypoplasia (underdevelopment); bowed ulna (forearm bone) and femur (thigh bone), synostosis of the radius (forearm bone), humerus (upper arm bone), and trapezoid (hand bone); camptodactyly (fused interphalangeal joints in the fingers), thin ilial wings (outer pelvic plate), and renal malformations.

Other symptoms, such as cardiac malformations, proptotic exophthalmos (bulging eyes), arachnodactyly (spider-like fingers), as well as nasal, anal, and vaginal atresia (occlusion) have been reported.

Pathophysiology

Antley–Bixler syndrome has an autosomal recessive pattern of inheritance.

There are two distinct genetic mutations associated with the Antley–Bixler syndrome phenotype, which suggests the disorder may be genetically heterogeneous.

OMIM	Gene	Description
207410	FGFR2	Mutations found in the FGFR2 gene have been shown to cause synostosis and other formal skeletal, poly and syndactylic abnormalities found in Antley–Bixler and similar disorders.
201750	POR	A missense mutation in the cytochrome p450 oxydoreductase (POR) gene results in abnormal steroidogenesis related to the genital malformations often found in Antley-Bixler. In OMIM, this is classified as an "Antley–Bixler syndrome-like phenotype" and not as Antley–Bixler syndrome itself.

Antley–Bixler syndrome is inherited in an autosomal recessive pattern, which means the defective gene is located on an autosome, and two copies of the gene (one inherited from each parent) are required to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene but are usually not affected by the disorder.

Eponym

Antley–Bixler syndrome is named after Drs. Ray M. Antley (b. 1936) and David Bixler (b. 1940), who first described the disorder in a journal report from 1975.

See also

• Crouzon syndrome
• Jackson–Weiss syndrome
• Pfeiffer syndrome

External links

• GeneReviews/NIH/NCBI/UW entry on FGFR-Related Craniosynostosis Syndromes
• GeneReviews/NCBI/NIH/UW entry on Cytochrome P450 Oxidoreductase Deficiency