A case of Antley-Bixler syndrome caused by novel POR mutations / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child affected with multiple malformations.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from the child and her parents. Tro whole exome sequencing and bioinformatics analysis were carried out. Suspicted mutations were verified by PCR and Sanger sequencing.@*RESULTS@#The patient, a 2-year-old girl, presented with multiple malformations including dysmorphism, skeletal malformations and ambigulous genitalia. Through genetic testing, she was diagnosed with Antley-Bixler syndrome caused by compound heterozygous mutations of the POR gene (c.919G>T and c.1615G>A), which were derived from her mother and father, respectively.@*CONCLUSION@#The compound heterozygous mutations of the POR gene probably underlie the Antley-Bixler syndrome in this patient.

Advance in clinical research on Antley-Bixler syndrome / 中华医学遗传学杂志

Antley-Bixler syndrome (ABS) is a rare childhood disorder affecting skeletal development. Some patients may also have genital anomalies and impaired steroidogenesis. Diagnostic criteria for ABS has not been fully established, though craniosynostosis, midface hypoplasia and elbow synostosis are minimum requirements. The etiology of ABS is complex, which included autosomal dominant form caused by FGFR2 gene mutations, autosomal recessive form caused by POR gene mutations, and high oral dose of fluconazole during pregnancy. Patients may die from dyspnea due to upper respiratory tract obstruction. This review summarizes research progress on the clinical features, etiology, differential diagnosis, treatment and prevention of ABS.

A Case of Antley-Bixler Syndrome With a Novel Likely Pathogenic Variant (c.529G>C) in the POR Gene

No abstract available.

Traitement par la méthode d'Ilizarov des pseudarthroses des os longs

Introduction: Plusieurs techniques permettent de traiter les pseudarthroses des os longs. L'objectif de ce travail était d'évaluer les résultats préliminaires du traitement de ces lésions avec la méthode d'Ilizarov. Matériels et méthodes: Dans cette étude prospective réalisée entre janvier 2007 et juin 2013, 11 patients avec un âge moyen de26ansontétéopérésselon laméthoded'Ilizarov. Ils'agissaitdeneuf pseudarthroses post-traumatiques et deux pseudarthroses congénitales. La pseudarthrose siégeait au tibia (n=9), à l'humérus (n=1), et au fémur (n=1). Les modalités thérapeutiques étaient une compression pure sans abord du foyer (n=8), une compression après abord du foyer pour ablation de matériel d'ostéosynthèse et débridement (n=2) et une compression-distraction bifocale ou technique de « l'ascenseur »( n=1). Les résultats ont été analysés avec un recul moyen de 2,5 ans selon les critères anatomiques et fonctionnels de l'ASAMI. Résultats: La consolidation osseuse était obtenue chez 10 patients qui ont tous repris leur activité. Les résultats anatomiques étaient excellents (n=5), bons (n=4), moyen (n=1), et mauvais (échec) (n=1). Les résultats fonctionnels étaient excellents (n=3),bons(n=5), moyens(n=2) et mauvais (n=1). Conclusion: Dans cette étude préliminaire portant sur 11 cas de pseudarthroses des os longs traitées par la méthode d'Ilizarov la consolidation osseuse a été obtenue chez 10 patients qui ont tous repris leur activité. Cette technique est contraignante pour le chirurgien et le malade, mais constitue une alternative fiable pour le traitement des pseudarthroses

Two cases of Antley-Bixler syndrome caused by mutations in different genes, FGFR2 and POR

Antley-Bixler syndrome (ABS) is a rare form of syndromic craniosynostosis with additional systemic synostosis, including radiohumeral or radioulnar synostosis. Another characteristic feature of ABS is mid-facial hypoplasia that leads to airway narrowing after birth. ABS is associated with mutations in the FGFR2 and POR genes. Patients with POR mutations present with either skeletal manifestations or congenital adrenal hyperplasia with ambiguous genitalia. We report here two cases of ABS caused by mutations in FGFR2 and POR. Although the patients had craniosynostosis and radiohumeral synostosis in common and cranioplasty was performed in both cases, the male with POR mutations showed an elevated level of 17α-hydroxyprogesterone during newborn screening and was diagnosed with congenital adrenal hyperplasia by adrenocorticotropic hormone stimulation. This patient has been treated with hydrocortisone and fludrocortisone. He had no ambiguous genitalia but had bilateral cryptorchidism. On the other hand, the female with the FGFR2 mutation showed severe clinical manifestations: upper airway narrowing leading to tracheostomy, kyphosis of the cervical spine, and coccyx deformity. ABS shows locus heterogeneity, and mutations in two different genes can cause similar craniofacial and skeletal phenotypes. Because the long-term outcomes and inheritance patterns of the disease differ markedly, depending on the causative mutation, early molecular genetic testing is helpful.

Genetic Syndromes Associated with Craniosynostosis

Craniosynostosis is defined as the premature fusion of one or more of the cranial sutures. It leads not only to secondary distortion of skull shape but to various complications including neurologic, ophthalmic and respiratory dysfunction. Craniosynostosis is very heterogeneous in terms of its causes, presentation, and management. Both environmental factors and genetic factors are associated with development of craniosynostosis. Nonsyndromic craniosynostosis accounts for more than 70% of all cases. Syndromic craniosynostosis with a certain genetic cause is more likely to involve multiple sutures or bilateral coronal sutures. FGFR2, FGFR3, FGFR1, TWIST1 and EFNB1 genes are major causative genes of genetic syndromes associated with craniosynostosis. Although most of syndromic craniosynostosis show autosomal dominant inheritance, approximately half of patients are de novo cases. Apert syndrome, Pfeiffer syndrome, Crouzon syndrome, and Antley-Bixler syndrome are related to mutations in FGFR family (especially in FGFR2), and mutations in FGFRs can be overlapped between different syndromes. Saethre-Chotzen syndrome, Muenke syndrome, and craniofrontonasal syndrome are representative disorders showing isolated coronal suture involvement. Compared to the other types of craniosynostosis, single gene mutations can be more frequently detected, in one-third of coronal synostosis patients. Molecular diagnosis can be helpful to provide adequate genetic counseling and guidance for patients with syndromic craniosynostosis.

46,XX DSD and Antley-Bixler syndrome due to novel mutations in the cytochrome P450 oxidoreductase gene / DDS 46,XX e síndrome de Antley-Bixler causada por novas mutações no gene da enzima P450 oxidorredutase

Deficiency of the enzyme P450 oxidoreductase is a rare form of congenital adrenal hyperplasia with characteristics of combined and partial impairments in steroidogenic enzyme activities, as P450 oxidoreductase transfers electrons to CYP21A2, CYP17A1, and CYP19A1. It results in disorders of sex development and skeletal malformations similar to Antley-Bixley syndrome. We report the case of a 9-year-old girl who was born with virilized genitalia (Prader stage V), absence of palpable gonads, 46,XX karyotype, and hypergonadotropic hypogonadism. During the first year of life, ovarian cyst, partial adrenal insufficiency, and osteoarticular changes, such as mild craniosynostosis, carpal and tarsal synostosis, and limited forearm pronosupination were observed. Her mother presented severe virilization during pregnancy. The molecular analysis of P450 oxidoreductase gene revealed compound heterozygosis for the nonsense p.Arg223*, and the novel missense p.Met408Lys, inherited from the father and the mother, respectively. Arq Bras Endocrinol Metab. 2012;56(8):578-85.

A deficiência da enzima P450 oxidorredutase é uma forma rara de hiperplasia congênita da adrenal com características de inibição combinada e parcial de enzimas esteroidogênicas, pois a enzima P450 oxidorredutase participa da transferência de elétrons para as enzimas CYP21A2, CYP17A1 e CYP19A1. Essa deficiência causa um distúrbio do desenvolvimento do sexo e alterações esqueléticas semelhantes às da síndrome de Antley-Bixley. Relatamos o caso de uma menina, atualmente com 9 anos de idade, que apresentava ao nascimento genitais virilizados (Prader 5) sem gônadas palpáveis, com cariótipo 46,XX e hipogonadismo hipergonadotrófico. No primeiro ano de vida, foram observados cisto ovariano, insuficiência adrenal parcial e alterações osteoarticulares como leve craniossinostose, sinostose carpal e tarsal e limitação de pronossupinação dos membros superiores. Sua mãe apresentou intensa virilização durante a gestação. O estudo molecular do gene P450 oxidorredutase revelou a heterozigose composta das mutações nonsense p.Arg223* e da missense nova p.Met408Lys, herdadas do pai e da mãe, respectivamente. Arq Bras Endocrinol Metab. 2012;56(8):578-85.

Anesthetic management of a neonate with Antley-Bixler syndrome: A case report

Antley-Bixler syndrome is a congenital anomaly of multiple bones and cartilage, and this was first reported by Antley and Bixler in 1975. It is characterized by craniosynostosis, midface hypoplasia with choanal stenosis and atresia, radiohumeral synostosis and femoral bowing. This is sometimes accompanied by cardiac, renal, gastrointestinal and genital malformations. The risk of respiratory distress is high in the infants with this syndrome, and this is most commonly caused by choanal stenosis and atresia. Careful anesthetic management is needed for these infants because of the potential risk of a difficult airway and respiratory complications. We report here on our experience with the anesthetic management of a neonate with Antley-Bixler syndrome and we review the relevant literature.

A Case of Antley-Bixler Syndrome

Antley-Bixler syndrome is a very rare disese of characteristic feature of craniosynostosis, brachycephaly, midface hypoplasia, depressed nasal bridge, radiohumeral synostosis and bowing femur. We presented a case of Antley-Bixtler syndrome with brief review of lituratures.