Antley-Bixler Syndrome Phenotype: An inherited condition characterized by multiple malformations of CARTILAGE and bone including CRANIOSYNOSTOSIS; midface hypoplasia; radiohumeral SYNOSTOSIS; CHOANAL ATRESIA; femoral bowing; neonatal fractures; and multiple joint CONTRACTURES and, occasionally, urogenital, gastrointestinal or cardiac defects. In utero exposure to FLUCONAZOLE, as well as mutations in at least two separate genes are associated with this condition - POR (encoding P450 (cytochrome) oxidoreductase (NADPH-FERRIHEMOPROTEIN REDUCTASE)) and FGFR2 (encoding FIBROBLAST GROWTH FACTOR RECEPTOR 2).Synostosis: A union between adjacent bones or parts of a single bone formed by osseous material, such as ossified connecting cartilage or fibrous tissue. (Dorland, 27th ed)Craniosynostoses: Premature closure of one or more CRANIAL SUTURES. It often results in plagiocephaly. Craniosynostoses that involve multiple sutures are sometimes associated with congenital syndromes such as ACROCEPHALOSYNDACTYLIA; and CRANIOFACIAL DYSOSTOSIS.Syndrome: A characteristic symptom complex.Abnormalities, MultipleNADPH-Ferrihemoprotein Reductase: A flavoprotein that catalyzes the reduction of heme-thiolate-dependent monooxygenases and is part of the microsomal hydroxylating system. EC 1.6.2.4.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Ankylosis: Fixation and immobility of a joint.Chromosomes, Human, Pair 21: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Upper Extremity Deformities, Congenital: Congenital structural abnormalities of the UPPER EXTREMITY.Down Syndrome: A chromosome disorder associated either with an extra chromosome 21 or an effective trisomy for chromosome 21. Clinical manifestations include hypotonia, short stature, brachycephaly, upslanting palpebral fissures, epicanthus, Brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, Simian crease, and moderate to severe INTELLECTUAL DISABILITY. Cardiac and gastrointestinal malformations, a marked increase in the incidence of LEUKEMIA, and the early onset of ALZHEIMER DISEASE are also associated with this condition. Pathologic features include the development of NEUROFIBRILLARY TANGLES in neurons and the deposition of AMYLOID BETA-PROTEIN, similar to the pathology of ALZHEIMER DISEASE. (Menkes, Textbook of Child Neurology, 5th ed, p213)