Antley-Bixler syndrome (ABS) arising from P450 oxidoreductase deficiency (PORD) is a rare, distinct craniosynostosis syndrome, accompanied by ambiguous genitalia and impaired steroidogenesis. It is reported that this disorder is caused by mutations in the P450 oxidoreductase (POR; OMIM #124015) gene via autosomal recessive inheritance. In this study, we performed a molecular analysis to verify the genetic etiology of ABS in an infant. Initially, medical exome sequencing was applied using the parents' peripheral blood genome DNA. Next, bidirectional Sanger sequencing and quantitative real-time PCR (qRT-PCR) were conducted to confirm the sequencing results. The infant was diagnosed as ABS at birth, with typical midface hypoplasia, craniosynostosis, femoral bowing, radio-ulnar synostosis, and genital anomalies. She died two months later due to severe pneumonia and congenital heart disease. The medical exome sequencing and Sanger sequencing revealed the missense mutation c.1370G>A (p.R457H) in exon 12 of POR was inherited from the father. In addition, the qRT-PCR analysis verified an exon 5 microdeletion in the POR gene of the infant and her mother. While p.R457H is a well-known pathogenic mutation, the POR exon 5 deletion is absent from the public databases. However, it is classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines based on the evidence of PVS1, PM2, and PM3. In conclusion, this infant with ABS carried compound heterozygotic mutations in the POR gene; one was a paternal missense mutation, and the other was a maternal novel microdeletion. The mutations were inherited from the paternal grandfather and maternal grandfather, respectively. This detailed case report enriches our knowledge of the POR mutation spectrum and ABS pathogenesis.

Conventionally, patients with combined rare diseases are often difficult to diagnose. This is because some clinicians tend to consider the multiple disease symptoms as the presentation of a complicated "syndrome." This pattern of thinking also confines their way of filtering pathogenic mutations. Some real pathogenic mutations might be ignored due to not covering all disease presentations. Here we report the case of a girl who was suffering from spherocytosis and Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis. She remained undiagnosed even after targeted gene detection before. However, after performing next-generation sequencing and analyzing the sequencing data, we identified two mutations: c.2978T > A in ANK1 and c.1370G > A in POR. Our findings and experiences in diagnosing these mutations could contribute to the existing knowledge on the clinical and genetic diagnosis of patients with disease presentations in multiple systems.

Can cytochrome P450 oxidoreductase deficiency (PORD) be revealed in adult women with menstrual disorders and/or infertility? PORD was biologically and genetically confirmed in five adult women with chronically elevated serum progesterone (P) who were referred for oligo-/amenorrhea and/or infertility. PORD is an autosomal recessive disease typically diagnosed in neonates and children with ambiguous genitalia and/or skeletal abnormalities. It is responsible for the decreased activity of several P450 enzymes, including CYP21A2, CYP17A1 and CYP19A1, that are involved in adrenal and/or gonadal steroidogenesis. Little is known about the optimal way to investigate and treat patients with adult-onset PORD. In this series, we report five adult females who were evaluated in three tertiary endocrine reproductive departments between March 2015 and September 2018. Five women aged 19-38 years were referred for unexplained oligo-/amenorrhea and/or infertility. Genetic testing excluded 21-hydroxylase deficiency (21OH-D), initially suspected due to the increased 17-hydroxyprogesterone (17-OHP) levels. Extensive phenotyping, steroid profiling by mass spectrometry, pelvic imaging and next-generation sequencing of 84 genes involved in gonadal and adrenal disorders were performed in all patients. IVF followed by frozen embryo transfer (ET) under glucocorticoid suppression therapy was performed for two patients. All patients had oligomenorrhea or amenorrhea. None had hyperandrogenism. Low-normal serum estradiol (E2) and testosterone levels contrasted with chronically increased serum P and 17-OHP levels, which further increased after adrenocorticotrophic hormone (ACTH) administration. Despite excessive P, 17OH-P and 21-deoxycortisol rise after ACTH stimulation suggesting non-classic 21OH-D, CYP21A2 sequencing did not support this hypothesis. Basal serum cortisol levels were low to normal, with inadequate response to ACTH in some women, suggesting partial adrenal insufficiency. All patients harbored rare biallelic POR mutations classified as pathogenic or likely pathogenic according to the American College of Medical Genetics and Genomics standards. Pelvic imaging revealed bilateral ovarian macrocysts in all women. IVF was performed for two women after retrieval of a normal oocyte number despite very low E2 levels during ovarian stimulation. Frozen ET under glucocorticoid suppression therapy led to successful pregnancies. The number of patients described here is limited and these data need to be confirmed on a larger number of women with non-classic PORD. The diagnosis of PORD must be considered in infertile women with chronically elevated P and 17OH-P levels and ovarian macrocysts. Differentiation of this entity from non-classic 21OH-D is important, as the multiple enzyme deficiency requires a specific management. Successful fertility induction is possible by IVF, providing that P levels be sufficiently suppressed by glucocorticoid therapy prior to implantation. No specific funding was used for this study. There are no potential conflicts of interest. N/A.

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. Cytochrome P450 oxidoreductase deficiency (PORD) is a disorder of steroidogenesis with a broad phenotypic spectrum including cortisol deficiency, altered sex steroid synthesis, disorders of sex development (DSD), and skeletal malformations of the Antley-Bixler syndrome (ABS) phenotype. Cortisol deficiency is usually partial, with some baseline cortisol production but failure to mount an adequate cortisol response in stress. Mild mineralocorticoid excess can be present and causes arterial hypertension, usually presenting in young adulthood. Manifestations of altered sex steroid synthesis include ambiguous genitalia/DSD in both males and females, large ovarian cysts in females, poor masculinization and delayed puberty in males, and maternal virilization during pregnancy with an affected fetus. Skeletal malformations can manifest as craniosynostosis, mid-face retrusion with proptosis and choanal stenosis or atresia, low-set dysplastic ears with stenotic external auditory canals, hydrocephalus, radiohumeral synostosis, neonatal fractures, congenital bowing of the long bones, joint contractures, arachnodactyly, and clubfeet; other anomalies observed include urinary tract anomalies (renal pelvic dilatation, vesicoureteral reflux). Cognitive impairment is of minor concern and likely associated with the severity of malformations; studies of developmental outcomes are lacking. The diagnosis of PORD can be established by urinary steroid profiling using gas chromatography / mass spectrometry (GC/MS), which documents combined impairment of 17α-hydroxylase (CYP17A1) and 21-hydroxylase (CYP21A2) enzymatic activity located at key branch points of cortisol, aldosterone, and sex steroid synthesis. Identification of biallelic POR pathogenic variants on molecular genetic testing confirms the diagnosis. Molecular genetic testing is desirable for all individuals affected by PORD to confirm the diagnosis, but is mandatory if clinical and laboratory features are inconclusive. Treatment of manifestations: Glucocorticoid replacement therapy for cortisol deficiency including stress-dose cover in intercurrent illness; surgery as needed for craniosynostosis, hypospadias, and cryptorchidism in males and clitoromegaly and vaginal hypoplasia in females; dihydrotestosterone treatment has been successful in some males with micropenis; testosterone replacement in males in whom testosterone levels remain relatively low after onset of puberty; females with absent pubertal development may require estrogen replacement therapy; treatment with estradiol to reduce the size of ovarian cysts; endotracheal intubation, nasal stints or tracheotomy, and tracheostomy as needed; physical and occupational therapy for joint contractures and help with fine and gross motor skills. Prevention of secondary complications: Supplementation with appropriate steroid hormones in individuals who are deficient has helped alleviate adrenal crisis, lack of or poor pubertal development in males and females, sleepiness, and fatigue. Early intervention services may improve the outcome for individuals at risk for developmental delays and learning difficulties. Surveillance: Evaluations with a specialist tertiary pediatric endocrine service throughout childhood to closely monitor development and adjust steroid supplementation. Periodic formal developmental assessments in centers with expertise and experience in developmental testing. Evaluation of relatives at risk: It is appropriate to evaluate apparently asymptomatic older and younger sibs of a proband in order to identify as early as possible those who would benefit from initiation of treatment and preventive measures. PORD is inherited in an autosomal recessive manner. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk family members and prenatal genetic testing for pregnancies at increased risk are possible if the POR pathogenic variants have been identified in the family. In addition, noninvasive testing of maternal urine steroid excretion by GC/MS can indicate whether the unborn child is affected by PORD from gestational week 12 onwards.