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Zhang J, Woo KL, Hai Y, Wang S, Lin Y, Huang Y, Peng X, Wu H, Zhang S, Yan L, Li Y. Congenital adrenal hyperplasia due to P450 oxidoreductase deficiency. Front Endocrinol (Lausanne) 2022; 13:1020880. [PMID: 36518257 PMCID: PMC9742467 DOI: 10.3389/fendo.2022.1020880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To raise awareness of Cytochrome P450 Oxidoreductase Deficiency (PORD, a rare form of congenital adrenal hyperplasia (CAH), through a case of pregnant woman with virilization symptoms. CASE DESCRIPTION A 30-year-old Chinese woman was referred to hospital after 7 years of presenting signs of virilization, including voice deepening, acromegaly, hirsutism, clitoromegaly, and acne. These symptoms appeared since her third gestation. Her second birth died 9 hours after birth and had signs of clitoris hypertrophy. Her third born was a son who presented with flat nose, radius and humerus bone malformation, and small penis at birth. Panel of POR-related genetic tests revealed that the patient carried c.1370 G>A (p.R457H), which is a POR heterozygous gene, while her husband carried a POR heterozygous gene as well, c.1379 C>A (p.S460Y). Two heterozygous mutations of the POR were found in her son: c.1370 G>A and c.1379 C>A. In PORD, c.1370 G>A (p.R457H) was reported as a susceptible gene, while c.1379 C>A (p.S460Y) has not been reported as responsible for the disease so far. DISCUSSION AND LITERATURE REVIEW PORD is a rare form of CAH and caused by POR gene mutations. Most PORD patients are identified and diagnosed in pediatrics department. Internal medicine and obstetrics physicians are unfamiliar with the disease. As clinical manifestations are diverse, PORD could be easy to miss or to be misdiagnosed. Typical clinical manifestation includes adrenal insufficiency-related symptoms, such as bone malformations and sexual development disorders. PORD is diagnosed through genetic testing. Investigations of steroid metabolic products in urine through gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry are also helpful for the diagnosis, but neither of them are widely available in China. In this case, the patient had a history of infertility, and her third child was born with congenital defect and carried a PORD-related gene. In general clinical practice, if a pregnant woman presents with abnormal virilization symptoms, CAH possibilities should be considered, including rare causes such as PORD. CONCLUSION PORD is a rare autosomal recessive genetic disease. We summarised the clinical characteristics and genotypes that were previously reported in the Chinese population and identified a novel mutation.
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Affiliation(s)
- Jin Zhang
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
- *Correspondence: Jin Zhang, ; Li Yan, ; Yan Li,
| | - Kwan Leong Woo
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yongxiong Hai
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shimin Wang
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
- Department of Endocrinology, Jiangmen Central Hospital, Jiangmen, China
| | - Ying Lin
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ying Huang
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
- Department of Endocrinology and Metabolism, Zhuhai People's Hospital, Zhuhai, China
| | - Xiaofang Peng
- Cellular and Molecular Diagnostics Center, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - HongShi Wu
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shaoling Zhang
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Li Yan
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
- *Correspondence: Jin Zhang, ; Li Yan, ; Yan Li,
| | - Yan Li
- Department of Endocrinology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
- *Correspondence: Jin Zhang, ; Li Yan, ; Yan Li,
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Lee Y, Choi JH, Oh A, Kim GH, Park SH, Moon JE, Ko CW, Cheon CK, Yoo HW. Clinical, endocrinological, and molecular features of four Korean cases of cytochrome P450 oxidoreductase deficiency. Ann Pediatr Endocrinol Metab 2020; 25:97-103. [PMID: 32615689 PMCID: PMC7336261 DOI: 10.6065/apem.1938152.076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/16/2019] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Cytochrome P450 oxidoreductase (POR) deficiency is a rare autosomal recessive disorder caused by mutations in the POR gene encoding an electron donor for all microsomal P450 enzymes. It is characterized by adrenal insufficiency, ambiguous genitalia, maternal virilization during pregnancy, and skeletal dysplasia. In this study, we investigated the clinical, hormonal, and molecular characteristics of patients with POR deficiency in Korea. METHODS This study included four patients with POR deficiency confirmed by biochemical and molecular analysis of POR. Clinical and biochemical findings were reviewed retrospectively. Mutation analysis of POR was performed by Sanger sequencing after polymerase chain reaction amplification of all coding exons and the exon-intron boundaries. RESULTS All patients presented with adrenal insufficiency and ambiguous genitalia regardless of their genetic sex. Two patients harbored homozygous p.R457H mutations in POR and presented with adrenal insufficiency and genital ambiguity without skeletal phenotypes. The other two patients with compound heterozygous mutations of c.[1329_1330insC];[1370G>A] (p.[I444Hfs*6];[R457H]) manifested skeletal abnormalities, such as craniosynostosis and radiohumeral synostosis, suggesting Antley-Bixler syndrome. They also had multiple congenital anomalies involving heart, kidney, and hearing ability. All patients were treated with physiologic doses of oral hydrocortisone. CONCLUSION We report the cases of 4 patients with POR deficiency identified by mutation analysis of POR. Although the study involved a small number of patients, the POR p.R457H mutation was the most common, suggesting founder effect in Korea. POR deficiency is rare and can be misdiagnosed as 21-hydroxylase or 17α-hydroxylase/17,20-lyase deficiency. Therefore, molecular analysis is critical for confirmatory diagnosis.
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Affiliation(s)
- Yena Lee
- Depar tment of Pediatrics, Asan Medical Center, Children’s Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Jin-Ho Choi
- Depar tment of Pediatrics, Asan Medical Center, Children’s Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Arum Oh
- Depar tment of Pediatrics, Asan Medical Center, Children’s Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Gu-Hwan Kim
- Medical Genetics Center, Asan Medical Center, Children’s Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Sook-Hyun Park
- Department of Pediatrics, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Jung Eun Moon
- Department of Pediatrics, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Cheol Woo Ko
- Department of Pediatrics, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Chong-Kun Cheon
- Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University School of Medicine, Yangsan, Korea
| | - Han-Wook Yoo
- Depar tment of Pediatrics, Asan Medical Center, Children’s Hospital, University of Ulsan College of Medicine, Seoul, Korea,Address for correspondence: Han-Wook Yoo, MD, PhD Department of Pediatrics, Asan Medical Center Children’s Hospital, University of Ulsan College of Medicine, 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea Tel: +82-2-3010-3374 Fax: +82-2-473-3725 E-mail:
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3
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Oh J, Song JS, Park JE, Jang SY, Ki CS, Kim DK. A Case of Antley-Bixler Syndrome With a Novel Likely Pathogenic Variant (c.529G>C) in the POR Gene. Ann Lab Med 2019; 37:559-562. [PMID: 28841001 PMCID: PMC5587836 DOI: 10.3343/alm.2017.37.6.559] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 03/29/2017] [Accepted: 07/10/2017] [Indexed: 11/29/2022] Open
Affiliation(s)
- Jongwon Oh
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ju Sun Song
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jong Eun Park
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Shin Yi Jang
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Chang Seok Ki
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
| | - Duk Kyung Kim
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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Abstract
Congenital adrenal hyperplasia (CAH) refers to a group of autosomal recessive disorders due to single-gene defects in the various enzymes required for cortisol biosynthesis. CAH represents a continuous phenotypic spectrum with more than 95% of all cases caused by 21-hydroxylase deficiency. Genotyping is an important tool in confirming the diagnosis or carrier state, provides prognostic information on disease severity, and is essential for genetic counseling. In this article, the authors provide an in-depth discussion on the genetics of CAH, including genetic diagnosis, molecular analysis, genotype-phenotype relationships, and counseling of patients and their families.
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Affiliation(s)
- Fady Hannah-Shmouni
- Section on Endocrinology and Genetics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 10, CRC, Room 1-2740, 10 Center Drive, MSC 1932, Bethesda, MD 20892-1932, USA
| | - Wuyan Chen
- Clinical DNA Testing and DNA Banking, PreventionGenetics, 3800 South Business Park Avenue, Marshfield, WI 54449, USA
| | - Deborah P Merke
- Section on Endocrinology and Genetics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 10, CRC, Room 1-2740, 10 Center Drive, MSC 1932, Bethesda, MD 20892-1932, USA; Department of Pediatrics, The National Institutes of Health Clinical Center, 10 Center Drive, Bethesda, MD 20892-1932, USA.
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Bai Y, Li J, Wang X. Cytochrome P450 oxidoreductase deficiency caused by R457H mutation in POR gene in Chinese: case report and literature review. J Ovarian Res 2017; 10:16. [PMID: 28288674 PMCID: PMC5348910 DOI: 10.1186/s13048-017-0312-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/07/2017] [Indexed: 11/23/2022] Open
Abstract
Background Cytochrome P450 oxidoreductase deficiency (PORD) is a rare disease exhibiting a variety of clinical manifestations. It can be difficult to differentiate with other diseases such as 21-hydroxylase deficiency (21-OHD), polycystic ovary syndrome (PCOS) and Antley–Bixler syndrome (ABS). Nearly 100 cases of PORD have been reported worldwide. However, the genetic characters and clinical management are still unclear, especially in China. Case presentation In this study, we report a 27-year-old female Chinese patient who first presented with amenorrhea and recurrence of large ovary cyst. She was misdiagnosed with PCOS and non-classical 21-OHD due to ovary cysts and elevated 17-hydroxy-progesterone. The patient’s complaining of a mild difficulty of bending the metacarpophalangeal joints reminded us to consider PORD, which usually presents with skeletal deformities and sexual dysfunction. The diagnosis of PORD was confirmed by genetic analyses, which showed the patient harboring a homozygous missense mutation in the POR gene (R457H) and her parents carrying the heterozygous mutation. The patient was treated with low-dose corticosteroids and estrogen/progesterone sequential therapy, and her ovarian cyst gradually reduced with regular menstruation in the follow-up. Moreover, the clinical and genetic characteristics of 104 previously reported PORD cases were also summarized and analyzed. Conclusions PORD is a very rare disease which can be easily misdiagnosed in mild cases. Clinicians should keep in mind of this disease in patients with sexual dysfunction, especially combined with special skeletal deformities. Our data could provide a consciously understanding of this disease for clinic practicers. Low-dose corticosteroids combined with estrogen/progesterone sequential therapy will be effective in PORD patients with recurrence of large ovary cyst. The fact that the reported PORD patients in China carrying an identical variant R457H in POR gene also give us a viewpoint that R457H mutation in POR gene maybe important in causing PORD in Chinese as same as in Japanese.
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Affiliation(s)
- Yang Bai
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Nanjing North Street, NO 155, Shenyang, 110001, People's Republic of China
| | - Jinhui Li
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Nanjing North Street, NO 155, Shenyang, 110001, People's Republic of China
| | - Xiaoli Wang
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, Nanjing North Street, NO 155, Shenyang, 110001, People's Republic of China.
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6
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Flück CE, Pandey AV. Impact on CYP19A1 activity by mutations in NADPH cytochrome P450 oxidoreductase. J Steroid Biochem Mol Biol 2017; 165:64-70. [PMID: 27032764 DOI: 10.1016/j.jsbmb.2016.03.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 03/20/2016] [Accepted: 03/22/2016] [Indexed: 11/23/2022]
Abstract
Cytochrome P450 aromatase (CYP19A1), in human placenta metabolizes androgens to estrogens and uses reduced nicotinamide adenine dinucleotide phosphate through cytochrome P450 oxidoreductase (POR) for the energy requirements of its metabolic activities. Mutations in the human POR lead to congenital adrenal hyperplasia due to loss of activities of several steroid metabolizing enzymatic reactions conducted by the cytochrome P450 proteins located in the endoplasmic reticulum. Effect of POR mutations on different P450 activities depend on individual partner proteins. In this report we have studied the impact of mutations found in the POR on the enzymatic activity of CYP19A1. We expressed wild type as well mutant human POR proteins in bacteria and purified the recombinant proteins, which were then used in an in vitro reconstitution system in combination with CYP19A1 and lipids for enzymatic analysis. We found that several mutations as well as polymorphisms in human POR can cause reduction of CYP19A1 activity. This would affect metabolism of estrogens in people with variations of POR allele. The POR mutants Y181D and R616X were found to have no activity in supporting CYP19A1 reactions. The POR mutations Y607C and delF646 showed a loss of 60-90% activity and two polymorphic forms of POR, R316W and G413S showed similar to WT activity. One POR variant, Q153R had almost double the activity of WT. Loss of CYP19A1 activity may contribute to disordered steroidogenesis in female patients with POR mutations as well as in mothers with POR variants carrying a male child.
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Affiliation(s)
- Christa E Flück
- Pediatric Endocrinology, Diabetology and Metabolism, University Children's Hospital Bern, and Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Amit V Pandey
- Pediatric Endocrinology, Diabetology and Metabolism, University Children's Hospital Bern, and Department of Clinical Research, University of Bern, Bern, Switzerland.
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Hatta FHM, Aklillu E. P450 (Cytochrome) Oxidoreductase Gene (POR) Common Variant (POR*28) Significantly Alters CYP2C9 Activity in Swedish, But Not in Korean Healthy Subjects. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2016; 19:777-81. [PMID: 26669712 DOI: 10.1089/omi.2015.0159] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
CYP2C9 enzyme contributes to the metabolism of several pharmaceuticals and xenobiotics and yet displays large person-to-person and interethnic variation. Understanding the mechanisms of CYP2C9 variation is thus of immense importance for personalized medicine and rational therapeutics. A genetic variant of P450 (cytochrome) oxidoreductase (POR), a CYP450 redox partner, is reported to influence CYP2C9 metabolic activity in vitro. We investigated the impact of a common variant, POR*28, on CYP2C9 metabolic activity in humans. 148 healthy Swedish and 146 healthy Korean volunteers were genotyped for known CYP2C9 defective variant alleles (CYP2C9*2, *3). The CYP2C9 phenotype was determined using a single oral dose of 50 mg losartan. Excluding oral contraceptive (OC) users and carriers of 2C9*2 and *3 alleles, 117 Korean and 65 Swedish were genotyped for POR*5, *13 and *28 using Taqman assays. The urinary losartan to its metabolite E-3174 metabolic ratio (MR) was used as an index of CYP2C9 metabolic activity. The allele frequency of the POR*28 variant allele in Swedes and Koreans was 29% and 44%, respectively. POR*5 and *13 were absent in both study populations. Considering the CYP2C9*1/*1 genotypes only, the CYP2C9 metabolic activity was 1.40-fold higher in carriers of POR*28 allele than non-carriers among Swedes (p = 0.02). By contrast, no influence of the POR*28 on CYP2C9 activity was found in Koreans (p = 0.68). The multivariate analysis showed that ethnicity, POR genotype, and smoking were strong predictors of CYP2C9 MR (p < 0.05). This is the first report to implicate the importance of POR*28 genetic variation for CYP2C9 metabolic activity in humans. These findings contribute to current efforts for global personalized medicine and using medicines by taking into account pharmacogenetic and phenotypic variations.
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Affiliation(s)
- Fazleen H M Hatta
- 1 Department of Laboratory Medicine, Karolinska Institutet, Division of Clinical Pharmacology, Karolinska University Hospital , Huddinge, Sweden .,2 Faculty of Pharmacy, Universiti Teknologi MARA , Selangor, Malaysia
| | - Eleni Aklillu
- 1 Department of Laboratory Medicine, Karolinska Institutet, Division of Clinical Pharmacology, Karolinska University Hospital , Huddinge, Sweden
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8
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McCammon KM, Panda SP, Xia C, Kim JJP, Moutinho D, Kranendonk M, Auchus RJ, Lafer EM, Ghosh D, Martasek P, Kar R, Masters BS, Roman LJ. Instability of the Human Cytochrome P450 Reductase A287P Variant Is the Major Contributor to Its Antley-Bixler Syndrome-like Phenotype. J Biol Chem 2016; 291:20487-502. [PMID: 27496950 PMCID: PMC5034044 DOI: 10.1074/jbc.m116.716019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 07/18/2016] [Indexed: 11/06/2022] Open
Abstract
Human NADPH-cytochrome P450 oxidoreductase (POR) gene mutations are associated with severe skeletal deformities and disordered steroidogenesis. The human POR mutation A287P presents with disordered sexual development and skeletal malformations. Difficult recombinant expression and purification of this POR mutant suggested that the protein was less stable than WT. The activities of cytochrome P450 17A1, 19A1, and 21A2, critical in steroidogenesis, were similar using our purified, full-length, unmodified A287P or WT POR, as were those of several xenobiotic-metabolizing cytochromes P450, indicating that the A287P protein is functionally competent in vitro, despite its functionally deficient phenotypic behavior in vivo Differential scanning calorimetry and limited trypsinolysis studies revealed a relatively unstable A287P compared with WT protein, leading to the hypothesis that the syndrome observed in vivo results from altered POR protein stability. The crystal structures of the soluble domains of WT and A287P reveal only subtle differences between them, but these differences are consistent with the differential scanning calorimetry results as well as the differential susceptibility of A287P and WT observed with trypsinolysis. The relative in vivo stabilities of WT and A287P proteins were also examined in an osteoblast cell line by treatment with cycloheximide, a protein synthesis inhibitor, showing that the level of A287P protein post-inhibition is lower than WT and suggesting that A287P may be degraded at a higher rate. Current studies demonstrate that, unlike previously described mutations, A287P causes POR deficiency disorder due to conformational instability leading to proteolytic susceptibility in vivo, rather than through an inherent flavin-binding defect.
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Affiliation(s)
- Karen M McCammon
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Satya P Panda
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Chuanwu Xia
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jung-Ja P Kim
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Daniela Moutinho
- the Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/FCM, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal
| | - Michel Kranendonk
- the Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/FCM, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal
| | - Richard J Auchus
- the Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Eileen M Lafer
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Debashis Ghosh
- the Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Pavel Martasek
- the Department of Pediatrics, First Faculty of Medicine, Charles University in Prague and General University Hospital, 116 36 Prague 1, Czech Republic
| | - Rekha Kar
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Bettie Sue Masters
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229,
| | - Linda J Roman
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229,
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9
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Fukami M, Ogata T. Cytochrome P450 oxidoreductase deficiency: rare congenital disorder leading to skeletal malformations and steroidogenic defects. Pediatr Int 2014; 56:805-808. [PMID: 25294558 DOI: 10.1111/ped.12518] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 06/20/2014] [Accepted: 09/24/2014] [Indexed: 11/27/2022]
Abstract
Cytochrome P450 oxidoreductase (POR) deficiency (PORD) is a newly characterized disorder. PORD is caused by homozygous or compound heterozygous mutations in POR encoding an electron donor for several microsomal enzymes such as CYP21A2, CYP17A1, CYP19A1, CYP51A1, and CYP26A1-C1. Molecular defects of PORD include a Japanese founder mutation p.R457H, as well as various missense, nonsense, frameshift, and splice-site mutations and exonic deletions. PORD leads to unique skeletal malformations referred to as Antley-Bixler syndrome, in addition to 46,XX and 46,XY disorders of sex development, pubertal failure, adrenal dysfunction, and maternal virilization during pregnancy. Such clinical features are ascribable to impaired activities of the POR-dependent microsomal enzymes. PORD represents one form of congenital adrenal hyperplasia, although it can occur as a congenital malformation syndrome and a disorder of sex development. Phenotypic severity of PORD is highly variable and only partly depends on the residual activity of the mutant proteins. It is possible that PORD remains undiagnosed in several patients. Detailed hormonal assessment and molecular analysis are useful for diagnosis of PORD.
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Affiliation(s)
- Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tsutomu Ogata
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan.,Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Cheng X, Gu J, Klaassen CD. Adaptive hepatic and intestinal alterations in mice after deletion of NADPH-cytochrome P450 Oxidoreductase (Cpr) in hepatocytes. Drug Metab Dispos 2014; 42:1826-33. [PMID: 25147274 DOI: 10.1124/dmd.114.060053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 enzymes (P450) play an important role in first-pass metabolism in both the intestine and liver. NADPH-cytochrome P450 oxidoreductase (Cpr) is an essential electron transfer protein required for microsomal P450 activity. Mice with conditional knockout of Cpr in hepatocytes develop normally and survive even with complete loss of liver microsomal P450 activity. Our current studies were performed to determine whether alternative drug-metabolizing pathways increase in an attempt to maintain whole-body homeostasis. In addition to the liver, Cpr is mainly expressed in tissues such as lung, kidney, and gastrointestinal tract. In livers of H-Cpr-null mice, there is a marked increase in mRNA expression of phase I enzymes (Aldh1a1, 1a7, 3a2; Ces1b2, 2a6, and 2a12), antioxidant enzymes (Ho-1, Nqo1, and epoxide hydrolase), phase II enzymes (Ugt1a9; Gsta1/2, m3, m4, m6, t1, and t3; and Sult1a1 and 1d1), and drug transporters (Oatp1a4, Oct3, Mate1, Mdr1a, and Mrp3 and 4). In addition, glucuronide-conjugated bilirubin concentrations are doubled in serum of H-Cpr-null mice. Both constitutive androstane receptor (CAR) and nuclear factor erythroid 2-related factor 2 (Nrf2) protein in nuclei are higher in the livers of H-Cpr-null mice, indicating that CAR and Nrf2 are activated. In the small intestine of H-Cpr-null mice, mRNA expression of Cyp3a11 and Mdr1a, two genes critical for intestinal first-pass metabolism, are markedly up-regulated. In addition, nutrient (Pept1) and cholesterol (Npc1l1) transporters are induced in the small intestine of H-Cpr-null mice. In conclusion, in H-Cpr-null mice, adaptive regulation of alternative detoxification genes in liver and small intestine appear to partially compensate for the loss of microsomal P450 function in liver.
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Affiliation(s)
- Xingguo Cheng
- Department of Pharmaceutical Sciences, St. John's University, Queens, New York (X.C.); Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, New York (J.G.); and Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas (C.D.K.)
| | - Jun Gu
- Department of Pharmaceutical Sciences, St. John's University, Queens, New York (X.C.); Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, New York (J.G.); and Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas (C.D.K.)
| | - Curtis D Klaassen
- Department of Pharmaceutical Sciences, St. John's University, Queens, New York (X.C.); Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, New York (J.G.); and Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas (C.D.K.)
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11
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Polusani SR, Kar R, Riquelme MA, Masters BS, Panda SP. Regulation of gap junction function and Connexin 43 expression by cytochrome P450 oxidoreductase (CYPOR). Biochem Biophys Res Commun 2011; 411:490-5. [PMID: 21726529 DOI: 10.1016/j.bbrc.2011.06.132] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 06/18/2011] [Indexed: 11/28/2022]
Abstract
Cytochrome P450 oxidoreductase (CYPOR) is a microsomal electron-transferring enzyme containing both FAD and FMN as co-factors, which provides the reducing equivalents to various redox partners, such as cytochromes P450 (CYPs), heme oxygenase (HO), cytochrome b(5) and squalene monooxygenase. Human patients with severe forms of CYPOR mutation show bone defects such as cranio- and humeroradial synostoses and long bone fractures, known as Antley-Bixler-like Syndrome (ABS). To elucidate the role of CYPOR in bone, we knocked-down CYPOR in multiple osteoblast cell lines using RNAi technology. In this study, knock-down of CYPOR decreased the expression of Connexin 43 (Cx43), known to play a critical role in bone formation, modeling, and remodeling. Knock-down of CYPOR also decreased Gap Junction Intercellular Communication (GJIC) and hemichannel activity. Promoter luciferase assays revealed that the decrease in expression of Cx43 in CYPOR knock-down cells was due to transcriptional repression. Primary osteoblasts isolated from bone specific Por knock-down mice calvariae confirmed the findings in the cell lines. Taken together, our study provides novel insights into the regulation of gap junction function by CYPOR and suggests that Cx43 may play an important role(s) in CYPOR-mediated bone defects seen in patients.
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Affiliation(s)
- Srikanth R Polusani
- The University of Texas Health Science Center at San Antonio, Department of Biochemistry, San Antonio, TX 78229, United States
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Substrate-specific modulation of CYP3A4 activity by genetic variants of cytochrome P450 oxidoreductase. Pharmacogenet Genomics 2011; 20:611-8. [PMID: 20697309 DOI: 10.1097/fpc.0b013e32833e0cb5] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES CYP3A4 receives electrons from P450 oxidoreductase (POR) to metabolize about 50% of clinically used drugs. There is substantial inter-individual variation in CYP3A4 catalytic activity that is not explained by CYP3A4 genetic variants. CYP3A4 is flexible and distensible, permitting it to accommodate substrates varying in shape and size. To elucidate the mechanisms of variability in CYP3A4 catalysis, we examined the effects of genetic variants of POR, and explored the possibility that substrate-induced conformational changes in CYP3A4 differentially affect the ability of POR variants to support catalysis. METHODS We expressed human CYP3A4 and four POR variants (Q153R, A287P, R457H, A503 V) in bacteria, reconstituted them in vitro and measured the Michaelis constant and maximum velocity with testosterone, midazolam, quinidine and erythromycin as substrates. RESULTS POR A287P and R457H had low activity with all substrates; Q153R had 76-94% of wild-type (WT) activity with midazolam and erythromycin, but 129-150% activity with testosterone and quinidine. The A503 V polymorphism reduced the CYP3A4 activity to 61-77% of WT with testosterone and midazolam, but had nearly WT activity with quinidine and erythromycin. CONCLUSION POR variants affect CYP3A4 activities. The impact of a POR variant on catalysis by CYP3A4 is substrate-specific, probably because of substrate-induced conformational changes in CYP3A4.
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Idkowiak J, O'Riordan S, Reisch N, Malunowicz EM, Collins F, Kerstens MN, Köhler B, Graul-Neumann LM, Szarras-Czapnik M, Dattani M, Silink M, Shackleton CHL, Maiter D, Krone N, Arlt W. Pubertal presentation in seven patients with congenital adrenal hyperplasia due to P450 oxidoreductase deficiency. J Clin Endocrinol Metab 2011; 96:E453-62. [PMID: 21190981 PMCID: PMC3124345 DOI: 10.1210/jc.2010-1607] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 11/16/2010] [Indexed: 01/02/2023]
Abstract
CONTEXT P450 oxidoreductase (POR) is a crucial electron donor to all microsomal P450 cytochrome (CYP) enzymes including 17α-hydroxylase (CYP17A1), 21-hydroxylase (CYP21A2) and P450 aromatase. Mutant POR causes congenital adrenal hyperplasia with combined glucocorticoid and sex steroid deficiency. P450 oxidoreductase deficiency (ORD) commonly presents neonatally, with disordered sex development in both sexes, skeletal malformations, and glucocorticoid deficiency. OBJECTIVE The aim of the study was to describe the clinical and biochemical characteristics of ORD during puberty. DESIGN Clinical, biochemical, and genetic assessment of seven ORD patients (five females, two males) presenting during puberty was conducted. RESULTS Predominant findings in females were incomplete pubertal development (four of five) and large ovarian cysts (five of five) prone to spontaneous rupture, in some only resolving after combined treatment with estrogen/progestin, GnRH superagonists, and glucocorticoids. Pubertal development in the two boys was more mildly affected, with some spontaneous progression. Urinary steroid profiling revealed combined CYP17A1 and CYP21A2 deficiencies indicative of ORD in all patients; all but one failed to mount an appropriate cortisol response to ACTH stimulation indicative of adrenal insufficiency. Diagnosis of ORD was confirmed by direct sequencing, demonstrating disease-causing POR mutations. CONCLUSION Delayed and disordered puberty can be the first sign leading to a diagnosis of ORD. Appropriate testosterone production during puberty in affected boys but manifest primary hypogonadism in girls with ORD may indicate that testicular steroidogenesis is less dependent on POR than adrenal and ovarian steroidogenesis. Ovarian cysts in pubertal girls may be driven not only by high gonadotropins but possibly also by impaired CYP51A1-mediated production of meiosis-activating sterols due to mutant POR.
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Affiliation(s)
- Jan Idkowiak
- Centre for Endocrinology, Diabetes and Metabolism, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Flück CE, Mullis PE, Pandey AV. Reduction in hepatic drug metabolizing CYP3A4 activities caused by P450 oxidoreductase mutations identified in patients with disordered steroid metabolism. Biochem Biophys Res Commun 2010; 401:149-53. [DOI: 10.1016/j.bbrc.2010.09.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 09/07/2010] [Indexed: 10/19/2022]
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Pandey AV, Flück CE, Mullis PE. Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase. Biochem Biophys Res Commun 2010; 400:374-8. [PMID: 20732302 DOI: 10.1016/j.bbrc.2010.08.072] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/17/2010] [Indexed: 11/28/2022]
Abstract
Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare form of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.
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Affiliation(s)
- Amit V Pandey
- Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern, Switzerland.
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Ko JM, Cheon CK, Kim GH, Yoo HW. A case of Antley-Bixler syndrome caused by compound heterozygous mutations of the cytochrome P450 oxidoreductase gene. Eur J Pediatr 2009; 168:877-80. [PMID: 18853185 DOI: 10.1007/s00431-008-0849-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 09/24/2008] [Indexed: 10/21/2022]
Abstract
Antley-Bixler syndrome (ABS) is a skeletal malformation syndrome primarily affecting the skull and limbs. Although causal mutations in the FGFR2 gene have been found in some patients, mutations in the electron donor enzyme P450 oxidoreductase gene (POR) have recently been found to cause ABS in other patients. In addition to skeletal malformations, POR deficiency also causes glucocorticoid deficiency and congenital adrenal hyperplasia with ambiguous genitalia in both sexes. Here, we report on a 7-month-old Korean girl with ABS and ambiguous genitalia who was confirmed by POR gene analysis. Our patient showed typical skeletal findings with brachycephaly, mid-face hypoplasia, and radiohumeral synostosis. She also had partial labial fusion and a single urogenital orifice, as well as increased 17alpha-hydroxyprogesterone levels, suggesting a 21-hydroxylase deficiency. Cortisol and DHEA-sulfate response to rapid adrenocorticotropic hormone (ACTH) stimulation was inadequate. Direct sequencing of the POR gene revealed compound heterozygous mutations (I444fsX449 and R457H). This is the first report of a Korean patient with ABS caused by POR gene mutations.
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Affiliation(s)
- Jung Min Ko
- Department of Pediatrics, Asan Medical Center, Children and Adolescent Hospital, University of Ulsan College of Medicine, Songpa-Gu, Seoul, Korea
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Fukami M, Nishimura G, Homma K, Nagai T, Hanaki K, Uematsu A, Ishii T, Numakura C, Sawada H, Nakacho M, Kowase T, Motomura K, Haruna H, Nakamura M, Ohishi A, Adachi M, Tajima T, Hasegawa Y, Hasegawa T, Horikawa R, Fujieda K, Ogata T. Cytochrome P450 oxidoreductase deficiency: identification and characterization of biallelic mutations and genotype-phenotype correlations in 35 Japanese patients. J Clin Endocrinol Metab 2009; 94:1723-31. [PMID: 19258400 DOI: 10.1210/jc.2008-2816] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
CONTEXT Cytochrome P450 oxidoreductase (POR) deficiency is a rare autosomal recessive disorder characterized by skeletal dysplasia, adrenal dysfunction, disorders of sex development (DSD), and maternal virilization during pregnancy. Although multiple studies have been performed for this condition, several matters remain to be clarified, including the presence of manifesting heterozygosity and the underlying factors for clinical variability. OBJECTIVE The objective of the study was to examine such unresolved matters by detailed molecular studies and genotype-phenotype correlations. PATIENTS Thirty-five Japanese patients with POR deficiency participated in the study. RESULTS Mutation analysis revealed homozygosity for R457H in cases 1-14 (group A), compound heterozygosity for R457H and one apparently null mutation in cases 15-28 (group B), and other combinations of mutations in cases 29-35 (group C). In particular, FISH and RT-PCR sequencing analyses revealed an intragenic microdeletion in one apparent R457H homozygote, transcription failure of apparently normal alleles in three R457H heterozygotes, and nonsense mediated mRNA decay in two frameshift mutation-positive cases examined. Genotype-phenotype correlations indicated that skeletal features were definitely more severe, and adrenal dysfunction, 46,XY DSD, and pubertal failure were somewhat more severe in group B than group A, whereas 46,XX DSD and maternal virilization during pregnancy were similar between two groups. Notable findings also included the contrast between infrequent occurrence of 46,XY DSD and invariable occurrence of 46,XX DSD and pubertal growth pattern in group A mimicking that of aromatase deficiency. CONCLUSIONS The results argue against the heterozygote manifestation and suggest that the residual POR activity reflected by the R457H dosage constitutes the underlying factor for clinical variability in some features but not other features, probably due to the simplicity and complexity of POR-dependent metabolic pathways relevant to each phenotype.
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Affiliation(s)
- Maki Fukami
- Research Institute, National Center for Child Health and Development, Tokyo 157-8535, Japan.
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Abstract
Congenital adrenal hyperplasia (CAH) is one of the most common inherited metabolic disorders. It comprises a group of autosomal recessive disorders caused by the deficiency of one of four steroidogenic enzymes involved in cortisol biosynthesis or in the electron donor enzyme P450 oxidoreductase (POR) that serves as electron donor to steroidogenic cytochrome P450 (CYP) type II enzymes. The biochemical and clinical phenotype depends on the specific enzymatic defect and the impairment of specific enzyme activity. Defects of steroid 21-hydroxylase (CYP21A2) and 11beta-hydroxylase (CYP11B1) only affect adrenal steroidogenesis, whereas 17alpha-hydroxylase (CYP17A1) and 3beta-hydroxysteroid dehydrogenase type 2 (HSD3B2) deficiency also impact on gonadal steroid biosynthesis. Inactivating POR gene mutations are the cause of CAH manifesting with apparent combined CYP17A1-CYP21A2 deficiency. P450 oxidoreductase deficiency (ORD) has a complex phenotype including two unique features not observed in any other CAH variant: skeletal malformations and severe genital ambiguity in both sexes.
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Affiliation(s)
- Nils Krone
- Centre for Endocrinology, Diabetes & Metabolism, School of Clinical & Experimental Medicine, Institute of Biomedical Research, Edgbaston, Birmingham, UK.
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Abstract
Multiple joint contractures, including radiohumeral synostosis, are the hallmark of Antley-Bixler syndrome (ABS). The detailed description of the skeletal aberration, however, focused in feet is scarce. We carried out the scrutiny for foot lesion in three ABS patients with POR (nicotinamide adenine dinucleotide phosphate-oxidase-cytochrome P450 oxidoreductase) gene mutations, one of whom had undergone surgical intervention for difficulty in walking. Radiographs in all three patients showed middle cuneiform-second metatarsal synostosis and the fourth brachymetapody, irrespective of the severity of their systemic manifestations. In addition, talocalcaneal synostosis, lateral cuneiform-cuboid synostosis, defects of middle phalanx, and distal phalanx-middle phalanx synostosis were found in at least two patients. In conclusion, we found distinctive constellations of foot abnormalities in the patients of ABS with POR gene mutation, which may be useful in planning the treatment strategy, as well as in the diagnostic process.
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21
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Abstract
Antley-Bixler syndrome is a congenital malformation syndrome that primarily manifests with craniofacial abnormalities but may include skeletal malformations. Some cases have been shown to be caused by fibroblast growth factor receptor 2 mutations and, recently, it was revealed that others are caused by mutations in the electron donor enzyme P450 oxidoreductase (POR). P450 oxidoreductase deficiency, however, is not only associated with the malformations but frequently presents with disordered sex development in affected patients of both sexes. Furthermore, biochemical work-up invariably reveals impairment of 17-hydroxylase and 21-hydroxylase activities, two steroidogenic enzymes dependent on electron transfer from POR. While we begin to gain insight into the pathogenesis of disease, detailed genotype-phenotype studies are still lacking and POR deficiency presents several challenges for research. Firstly, the exact pathogenesis of the skeletal malformations as a consequence of POR mutations is unclear, though impaired sterol biosynthesis has been implicated. Secondly, it needs to be explained, why the external genitalia in affected boys may appear undervirilized while affected girls can be severely virilized. Further evidence is required for the proposed alternative pathway in human androgen synthesis that might explain the apparently contradictory finding of low circulating androgens and severely virilised external genitalia in affected girls. Recent studies have provided evidence for a differential interaction of specific POR mutations with different electron-accepting P450 enzymes and this may provide the key for further understanding of the complex pathogenesis of this complex disease.
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Affiliation(s)
- Wiebke Arlt
- Division of Medical Sciences, School of Medicine University of Birmingham, Birmingham, UK.
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Flück CE, Nicolo C, Pandey AV. Clinical, structural and functional implications of mutations and polymorphisms in human NADPH P450 oxidoreductase. Fundam Clin Pharmacol 2007; 21:399-410. [PMID: 17635179 DOI: 10.1111/j.1472-8206.2007.00520.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome P450 proteins are involved in metabolism of drugs and xenobiotics. In the endoplasmic reticulum a single nicotinamide adenine dinucleotide phosphate (NADPH) P450 oxidoreductase (POR) supplies electrons to all microsomal P450s for catalytic activity. POR is a flavoprotein that contains both flavin mononucleotide and flavin adenine dinucleotide as cofactors and uses NADPH as the source of electrons. We have recently reported a number of POR mutations in the patients with disordered steroidogenesis. In the first report we had described missense mutations (A287P, R457H, V492E, C569Y, and V608F) identified in four patients with defects in steroid production. Each POR variant was produced as recombinant N-27 form of the enzyme in bacteria and as full-length form in yeast. Membranes from bacteria or yeast expressing normal or variant POR were purified and their activities were characterized in cytochrome c and CYP17A1 assays. Later we have published a larger study that described a whole range of POR mutations and characterized the mutants/polymorphisms A115V, T142A, M263V, Y459H, A503V, G539R, L565P, R616X, V631I, and F646del from the sequencing of patient DNA. We also studied POR variants Y181D, P228L, R316W, G413S, and G504R that were available in public databases or published literature. Three-dimensional structure of rat POR is known and we have used this structure to deduce the structure-function correlation of POR mutations in human. The missense mutations found in patients with disordered steroidogenesis are generally in the co-factor binding and functionally important domains of POR and the apparent polymorphisms are found in regions with lesser structural importance. A variation in POR can alter the activity of all microsomal P450s, and therefore, can affect the metabolism of drugs and xenobiotics even when the P450s involved are otherwise normal. It is important to study the genetic and biochemical basis of POR variants in human population to gain information about possible differences in P450 mediated reactions among the individuals carrying a variant or polymorphic form of POR that could impact their metabolism.
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Affiliation(s)
- Christa E Flück
- Department of Pediatrics Endocrinology, University Children's Hospital, Freiburgstrasse 15, 3010 Bern, Switzerland
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McCall AA, Kirsch CF, Ishiyama G, Ishiyama A. Otologic findings in Antley-Bixler syndrome: a clinical and radiologic case report. Int J Pediatr Otorhinolaryngol 2007; 71:1139-43. [PMID: 17482285 DOI: 10.1016/j.ijporl.2007.02.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 02/15/2007] [Accepted: 02/17/2007] [Indexed: 11/22/2022]
Abstract
Antley-Bixler syndrome (ABS) is characterized by craniofacial dysmorphism and radiohumeral synostosis with other associated anomalies. Prior studies have commonly described the entirety of the syndrome or the genetic abnormalities underlying the syndrome, however, no study has specifically addressed the otologic findings of ABS. We present a case of ABS, specifically focusing on the otologic ramifications of the disease, and provide recommendations for approaching the otologic management of these complex patients.
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Affiliation(s)
- Andrew A McCall
- Division of Otolaryngology, Head and Neck Surgery, UCLA, Los Angeles, CA, USA
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Scott RR, Gomes LG, Huang N, Van Vliet G, Miller WL. Apparent manifesting heterozygosity in P450 oxidoreductase deficiency and its effect on coexisting 21-hydroxylase deficiency. J Clin Endocrinol Metab 2007; 92:2318-22. [PMID: 17389698 DOI: 10.1210/jc.2006-2345] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT P450 oxidoreductase (POR) deficiency is a disorder of steroidogenesis affecting the microsomal P450 enzymes that use POR as an electron donor. The clinical presentation is variable; patients can be asymptomatic or can present with genital anomalies and the Antley-Bixler syndrome, characterized by craniosynostosis and other bony anomalies. Obligately heterozygous parents are normal. Combined POR and 21-hydroxylase deficiencies have not been reported. OBJECTIVE The aim was to explore the manifestations of combined deficiencies of 21-hydroxylase and POR and to search for lesions in apparent manifesting POR heterozygotes. PATIENTS AND METHODS A newborn female had craniosynostosis, severe salt wasting, minimal virilization, grossly elevated 17OH-progesterone, and minimally elevated androgens. DNA encoding 21-hydroxylase, POR, and fibroblast growth factor receptor 2 was sequenced. For POR, the first untranslated exon (exon 1U), 5' flanking DNA, and most introns were sequenced in five apparent manifesting POR heterozygotes. RESULTS CYP21B mutations were found on both alleles, proving classical 21-hydroxylase deficiency. Fibroblast growth factor receptor 2 exons 8 and 10 were normal. A POR mutation, A287P, was found only on the maternal allele. Five previously reported patients had POR mutations found on only one allele, but their clinical characteristics were indistinguishable from patients with mutations on both alleles. Sequencing of exon 1U, 274 bp of POR 5' flanking DNA, and 12 of the 15 POR introns did not identify additional mutations affecting gene expression or splicing. CONCLUSION Manifesting heterozygosity is a possible feature of POR deficiency and may ameliorate the findings in coexisting 21-hydroxylase deficiency.
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Affiliation(s)
- Rachel R Scott
- Pediatric Endocrinology, 672-S, University of California San Francisco, San Francisco, CA 94143-0434, USA
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Abstract
Congenital adrenal hyperplasia (CAH) comprises a group of autosomal recessive disorders, which are usually due to inactivating mutations in single enzymes involved in adrenal steroid biosynthesis. The characteristics of the biochemical and clinical phenotype depend on the specific enzymatic defect. In 21-hydroxylase and 11beta-hydroxylase deficiency only adrenal steroidogenesis is affected, whereas a defect in 3beta-hydroxysteroid dehydrogenase or 17alpha-hydroxylase also involves gonadal steroid biosynthesis. Recently, mutations in the electron donor enzyme P450 oxidoreductase were identified as the cause of CAH with apparent combined 17alpha-hydroxylase and 21-hydroxylase deficiency, thereby illustrating the impact of redox regulation enzymes on steroidogenesis. P450 oxidoreductase deficiency (ORD) has a complex phenotype including two unique features not observed in any other CAH variant, skeletal malformations and severe genital ambiguity in both sexes. Despite invariably low circulating androgens, females with ORD may present with virilized genitalia and mothers may suffer from virilization during pregnancy. This apparently contradictory finding may be explained by the existence of an alternative pathway in human androgen biosynthesis, with important implications for physiology and pathophysiology. This review discusses the biochemical and clinical presentation and the genetic and functional basis of the currently known CAH variants, with a specific focus on ORD.
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Affiliation(s)
- Nils Krone
- Institute of Biomedical Research, Division of Medical Sciences, University of Birmingham, Birmingham, UK
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