1
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Honour JW. The interpretation of immunometric, chromatographic and mass spectrometric data for steroids in diagnosis of endocrine disorders. Steroids 2024; 211:109502. [PMID: 39214232 DOI: 10.1016/j.steroids.2024.109502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 08/25/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024]
Abstract
The analysis of steroids for endocrine disorders is in transition from immunoassay of individual steroids to more specific chromatographic and mass spectrometric methods with simultaneous determination of several steroids. Gas chromatography (GC) and liquid chromatography (LC) coupled with mass spectrometry (MS) offer unrivalled analytical capability for steroid analysis. These specialist techniques were often judged to be valuable only in a research laboratory but this is no longer the case. In a urinary steroid profile up to 30 steroids are identified with concentrations and excretion rates reported in a number of ways. The assays must accommodate the wide range in steroid concentrations in biological fluids from micromolar for dehydroepiandrosterone sulphate (DHEAS) to picomolar for oestradiol and aldosterone. For plasma concentrations, panels of 5-20 steroids are reported. The profile results are complex and interpretation is a real challenge in order to inform clinicians of likely implications. Although artificial intelligence and machine learning will in time generate reports from the analysis this is a way off being adopted into clinical practice. This review offers guidance on current interpretation of the data from steroid determinations in clinical practice. Using this approach more laboratories can use the techniques to answer clinical questions and offer broader interpretation of the results so that the clinician can understand the conclusion for the steroid defect, and can be advised to program further tests if necessary and instigate treatment. The biochemistry is part of the patient workup and a clinician led multidisciplinary team discussion of the results will be required for challenging patients. The laboratory will have to consider cost implications, bearing in mind that staff costs are the highest component. GC-MS and LC-MS/MS analysis of steroids are the choices. Steroid profiling has enormous potential to improve diagnosis of adrenal disorders and should be adopted in more laboratories in favour of the cheap, non-specific immunological methods.
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Affiliation(s)
- John W Honour
- Institute for Women's Health, University College London, 74 Huntley Street, London WC1E 6AU, UK.
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2
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Wijaya M, Ma H, Zhang J, Du M, Li Y, Chen Q, Guo S. Aldosterone signaling defect in young infants: single-center report and review. BMC Endocr Disord 2021; 21:149. [PMID: 34243750 PMCID: PMC8272273 DOI: 10.1186/s12902-021-00811-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 06/28/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aldosterone (Ald) is a crucial factor in maintaining electrolyte and water homeostasis. Defect in either its synthesis or function causes salt wasting (SW) manifestation. This disease group is rare, while most reported cases are sporadic. This study aimed to obtain an overview of the etiology and clinical picture of patients with the above condition and report our rare cases. METHODS A combination of retrospective review and case studies was conducted at the Pediatric Endocrine unit of The First Affiliated Hospital Sun Yat Sen University from September 1989 to June 2020. RESULTS A total of 187 patients with SW were enrolled, of which 90.4% (n = 169) were diagnosed with congenital adrenal hyperplasia (CAH). SW type 21-hydroxylase deficiency accounted for 98.8% (n = 167) of CAH diagnosis, while 1.2% (n = 2) was of lipoid CAH. Non-CAH comprised 9.6% (n = 18) of the total patients whose etiologies included SF-1 gene mutation (n = 1), X-linked adrenal hypoplasia congenita (n = 9), aldosterone synthase deficiency (ASD, n = 4), and pseudo-hypoaldosteronism type 1 (PHA1, n = 1). Etiologies were not identified in three patients. All of patients with ASD and PHA1 exhibited SW syndrome in their early neonatal period. DNA sequencing showed mutations of CYP11B2 for P1-P4 and NR3C2 for P5. P1 and P2 were sibling brothers affected by compound heterozygous mutations of c.1121G > A (p.R374Q) and c.1486delC p.(L496fs); likewise, P4 was identified with compound heterozygous mutations of c.1200 + 1G > A and c.240-1 G > T; meanwhile P3 demonstrated c.1303G > A p.(G435S) homozygous mutation in CYP11B2 gene. Lastly, P5 showed c.1768 C > T p.(R590*) heterozygous mutation in the NR3C2 gene. CONCLUSION Etiology of infant with aldosterone defect was mostly congenital. Renal and adrenal imaging are recommended to exclude renal causes. If clinical picture is suggestive, normal plasma Ald in early infancy cannot rule out aldosterone insufficiency.
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Affiliation(s)
- Melati Wijaya
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
| | - Huamei Ma
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China.
| | - Jun Zhang
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
| | - Minlian Du
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
| | - Yanhong Li
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
| | - Qiuli Chen
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
| | - Song Guo
- Department of Pediatrics, The First affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan II Rd, Guangzhou, 510080, P. R. China
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3
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Mutlu GY, Taşdemir M, Kızılkan NU, Güran T, Hatun Ş, Kayserili H, Bilge I. A rare cause of chronic hyponatremia in an infant: Answers. Pediatr Nephrol 2020; 35:243-245. [PMID: 31428928 DOI: 10.1007/s00467-019-04337-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 08/07/2019] [Indexed: 11/24/2022]
Affiliation(s)
- Gül Yeşiltepe Mutlu
- Division of Pediatric Endocrinology, Department of Pediatrics, Koç University School of Medicine, Istanbul, Turkey
| | - Mehmet Taşdemir
- Division of Pediatric Nephrology, Department of Pediatrics, Koç University School of Medicine, Davutpaşa cad no:4 Topkapı, 34010, Istanbul, Turkey.
| | - Nuray Uslu Kızılkan
- Division of Pediatric Gastroenterology, Department of Pediatrics, Koç University School of Medicine, Istanbul, Turkey
| | - Tülay Güran
- Division of Pediatric Endocrinology, Department of Pediatrics, Marmara University School of Medicine, Istanbul, Turkey
| | - Şükrü Hatun
- Division of Pediatric Endocrinology, Department of Pediatrics, Koç University School of Medicine, Istanbul, Turkey
| | - Hülya Kayserili
- Department of Medical Genetics, Koç University School of Medicine, Istanbul, Turkey
| | - Ilmay Bilge
- Division of Pediatric Nephrology, Department of Pediatrics, Koç University School of Medicine, Davutpaşa cad no:4 Topkapı, 34010, Istanbul, Turkey
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4
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Parween S, DiNardo G, Baj F, Zhang C, Gilardi G, Pandey AV. Differential effects of variations in human P450 oxidoreductase on the aromatase activity of CYP19A1 polymorphisms R264C and R264H. J Steroid Biochem Mol Biol 2020; 196:105507. [PMID: 31669572 DOI: 10.1016/j.jsbmb.2019.105507] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 10/18/2019] [Accepted: 10/22/2019] [Indexed: 01/08/2023]
Abstract
Aromatase (CYP19A1) converts androgens into estrogens and is required for female sexual development and growth and development in both sexes. CYP19A1 is a member of cytochrome P450 family of heme-thiolate monooxygenases located in the endoplasmic reticulum and depends on reducing equivalents from the reduced nicotinamide adenine dinucleotide phosphate via the cytochrome P450 oxidoreductase coded by POR. Both the CYP19A1 and POR genes are highly polymorphic, and mutations in both these genes are linked to disorders of steroid biosynthesis. We have previously shown that R264C and R264H mutations in CYP19A1, as well as mutations in POR, reduce CYP19A1 activity. The R264C is a common polymorphic variant of CYP19A1, with high frequency in Asian and African populations. Polymorphic alleles of POR are found in all populations studied so far and, therefore, may influence activities of CYP19A1 allelic variants. So far, the effects of variations in POR on enzymatic activities of allelic variants of CYP19A1 or any other steroid metabolizing cytochrome P450 proteins have not been studied. Here we are reporting the effects of three POR variants on the aromatase activities of two CYP19A1 variants, R264C, and R264H. We used bacterially expressed and purified preparations of WT and variant forms of CYP19A1 and POR and constructed liposomes with embedded CYP19A1 and POR proteins and assayed the CYP19A1 activities using radiolabeled androstenedione as a substrate. With the WT-POR as a redox partner, the R264C-CYP19A1 showed only 15% of aromatase activity, but the R264H had 87% of aromatase activity compared to WT-CYP19A1. With P284L-POR as a redox partner, R264C-CYP19A1 lost all activity but retained 6.7% of activity when P284T-POR was used as a redox partner. The R264H-CYP19A1 showed low activities with both the POR-P284 L as well as the POR-P284 T. When the POR-Y607C was used as a redox partner, the R264C-CYP19A1 retained approximately 5% of CYP19A1 activity. Remarkably, The R264H-CYP19A1 had more than three-fold higher activity compared to WT-CYP19A1 when the POR-Y607C was used as the redox partner, pointing toward a beneficial effect. The slight increase in activity of R264C-CYP19A1 with the P284T-POR and the three-fold increase in activity of the R264H-CYP19A1 with the Y607C-POR point toward a conformational effect and role of protein-protein interaction governed by the R264C and R264H substitutions in the CYP19A1 as well as P284 L, P284 T and Y607C variants of POR. These studies demonstrate that the allelic variants of P450 when present with a variant form of POR may show different activities, and combined effects of variations in the P450 enzymes as well as in the POR should be considered when genetic data are available. Recent trends in the whole-exome and whole-genome sequencing as diagnostic tools will permit combined evaluation of variations in multiple genes that are interdependent and may guide treatment options by adjusting therapeutic interventions based on laboratory analysis.
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Affiliation(s)
- Shaheena Parween
- Pediatric Endocrinology, Diabetology, and Metabolism, Department of Pediatrics, University Children's Hospital Bern, 3010, Bern, Switzerland; Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
| | - Giovanna DiNardo
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, Torino, Italy
| | - Francesca Baj
- Pediatric Endocrinology, Diabetology, and Metabolism, Department of Pediatrics, University Children's Hospital Bern, 3010, Bern, Switzerland; Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland; Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, Torino, Italy
| | - Chao Zhang
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, Torino, Italy
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, Torino, Italy.
| | - Amit V Pandey
- Pediatric Endocrinology, Diabetology, and Metabolism, Department of Pediatrics, University Children's Hospital Bern, 3010, Bern, Switzerland; Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland.
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Storbeck KH, Schiffer L, Baranowski ES, Chortis V, Prete A, Barnard L, Gilligan LC, Taylor AE, Idkowiak J, Arlt W, Shackleton CHL. Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism. Endocr Rev 2019; 40:1605-1625. [PMID: 31294783 PMCID: PMC6858476 DOI: 10.1210/er.2018-00262] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/04/2019] [Indexed: 01/01/2023]
Abstract
Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.
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Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Lina Schiffer
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Elizabeth S Baranowski
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Paediatric Endocrinology and Diabetes, Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Vasileios Chortis
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Alessandro Prete
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Lise Barnard
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Lorna C Gilligan
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Angela E Taylor
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Jan Idkowiak
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Paediatric Endocrinology and Diabetes, Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
- NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, United Kingdom
| | - Cedric H L Shackleton
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- UCSF Benioff Children’s Hospital Oakland Research Institute, Oakland, California
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6
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Miao H, Yu Z, Lu L, Zhu H, Auchus RJ, Liu J, Jiang J, Pan H, Gong F, Chen S, Lu Z. Analysis of novel heterozygous mutations in the CYP11B2 gene causing congenital aldosterone synthase deficiency and literature review. Steroids 2019; 150:108448. [PMID: 31302112 DOI: 10.1016/j.steroids.2019.108448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 12/20/2022]
Abstract
Aldosterone synthase deficiency (ASD) is a rare autosomal recessive disorder characterized by severe hyperkalemia, salt loss, vomiting, severe dehydration and failure to thrive. ASD is a life-threatening electrolyte imbalance in infants resulting from mutations in CYP11B2. We described ASD in a Chinese male infant with vomiting, poor feeding and failure to thrive. He was mildly dehydrated, with a weight of 6 kg (-3.45 SDS) and length of 67 cm (-3.10 SDS). Laboratory tests showed hyponatremia (119 mmol/L), serum potassium 5.4 mmol/L, low plasma aldosterone and plasma renin activity (PRA) levels. Next-generation sequencing of his DNA revealed compound heterozygous mutations in CYP11B2, a known variant c.1391_1393delTGC (p.Leu464del, rs776404064) and a novel variant c.1294delA (p.Arg432Glyfs*37). The HEK-293T expression system was used to investigate the variants, demonstrating negligible aldosterone synthesis compared with WT CYP11B2. The patient started fludrocortisone and subsequently gained 3.2 kg of weight and normalized serum sodium (137 mmol/L). We further reviewed reported cases of ASD, summarizing clinical features and CYP11B2 mutations; missense and nonsense mutations are most frequent. Fludrocortisone treatment is essential for ASD, and the need for mineralocorticoid replacement wanes with age; eventually, therapy can be discontinued for many affected children. Our study broadens the ASD phenotypic spectrum and shows the efficiency of next-generation sequencing for patients with atypical clinical manifestations.
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Affiliation(s)
- Hui Miao
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Zhongxun Yu
- Department of Pediatrics, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Lin Lu
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
| | - Huijuan Zhu
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
| | - Richard J Auchus
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, Department of Pharmacology, and the Program for Disorders of Sexual Development, University of Michigan, Room 5560A, MSRBII, 1150 West Medical Center Drive, Ann Arbor, MI 48109, United States
| | - Jiayan Liu
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, Department of Pharmacology, and the Program for Disorders of Sexual Development, University of Michigan, Room 5560A, MSRBII, 1150 West Medical Center Drive, Ann Arbor, MI 48109, United States
| | - Jun Jiang
- The Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Hui Pan
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Fengying Gong
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Shi Chen
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Zhaolin Lu
- Key Laboratory of Endocrinology of National Health Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
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LI NIU, LI JUAN, DING YU, YU TINGTING, SHEN YONGNIAN, FU QIHUA, SHEN YIPING, HUANG XIAODONG, WANG JIAN. Novel mutations in the CYP11B2 gene causing aldosterone synthase deficiency. Mol Med Rep 2016; 13:3127-32. [DOI: 10.3892/mmr.2016.4906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 12/11/2015] [Indexed: 11/06/2022] Open
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8
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Nguyen HH, Eiden-Plach A, Hannemann F, Malunowicz EM, Hartmann MF, Wudy SA, Bernhardt R. Phenotypic, metabolic, and molecular genetic characterization of six patients with congenital adrenal hyperplasia caused by novel mutations in the CYP11B1 gene. J Steroid Biochem Mol Biol 2016; 155:126-34. [PMID: 26476331 DOI: 10.1016/j.jsbmb.2015.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/13/2015] [Accepted: 10/11/2015] [Indexed: 10/22/2022]
Abstract
Congenital adrenal hyperplasia (CAH) is an autosomal recessive inherited disorder of steroidogenesis. Steroid 11β-hydroxylase deficiency (11β-OHD) due to mutations in the CYP11B1 gene is the second most common form of CAH. In this study, 6 patients suffering from CAH were diagnosed with 11β-OHD using urinary GC-MS steroid metabolomics analysis. The molecular basis of the disorder was investigated by molecular genetic analysis of the CYP11B1 gene, functional characterization of splicing and missense mutations, and analysis of the missense mutations in a computer model of CYP11B1. All patients presented with abnormal clinical signs of hyperandrogenism. Their urinary steroid metabolomes were characterized by excessive excretion rates of metabolites of 11-deoxycortisol as well as metabolites of 11-deoxycorticosterone, and allowed definite diagnosis. Patient 1 carries compound heterozygous mutations consisting of a novel nonsense mutation p.Q102X (c.304C>T) in exon 2 and the known missense mutation p.T318R (c.953C>G) in exon 5. Two siblings (patient 2 and 3) were compound heterozygous carriers of a known splicing mutation c.1200+1G>A in intron 7 and a known missense mutation p.R448H (c.1343G>A) in exon 8. Minigene experiments demonstrated that the c.1200+1G>A mutation caused abnormal pre-mRNA splicing (intron retention). Two further siblings (patient 4 and 5) were compound heterozygous carriers of a novel missense mutation p.R332G (c.994C>G) in exon 6 and the known missense mutation p.R448H (c.1343G>A) in exon 8. A CYP11B1 activity study in COS-1 cells showed that only 11% of the enzyme activity remained in the variant p.R332G. Patient 6 carried a so far not described homozygous deletion g.2470_5320del of 2850 bp corresponding to a loss of the CYP11B1 exons 3-8. The breakpoints of the deletion are embedded into two typical 6 base pair repeats (GCTTCT) upstream and downstream of the gene. Experiments analyzing the influence of mutations on splicing and on enzyme function were applied as complementary procedures to genotyping and provided a rational basis for understanding the clinical phenotype of CAH.
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Affiliation(s)
- Huy-Hoang Nguyen
- Department of Biochemistry, Saarland University, D-66123 Saarbrücken, Campus B2.2, Germany; Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Vietnam
| | - Antje Eiden-Plach
- Department of Biochemistry, Saarland University, D-66123 Saarbrücken, Campus B2.2, Germany
| | - Frank Hannemann
- Department of Biochemistry, Saarland University, D-66123 Saarbrücken, Campus B2.2, Germany
| | - Ewa M Malunowicz
- Departments of Biochemistry and Experimental Medicine, The Children's Memorial Health Institute, 04-730 Warsaw, Poland
| | - Michaela F Hartmann
- Steroid Research &Mass Spectrometry Unit, Division of Pediatric Endocrinology and Diabetology, Center of Child and Adolescent Medicine, Justus-Liebig-University, Giessen, Germany
| | - Stefan A Wudy
- Steroid Research &Mass Spectrometry Unit, Division of Pediatric Endocrinology and Diabetology, Center of Child and Adolescent Medicine, Justus-Liebig-University, Giessen, Germany
| | - Rita Bernhardt
- Department of Biochemistry, Saarland University, D-66123 Saarbrücken, Campus B2.2, Germany.
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Functional analysis of novel splicing and missense mutations identified in the ASS1 gene in classical citrullinemia patients. Clin Chim Acta 2014; 438:323-9. [PMID: 25179242 DOI: 10.1016/j.cca.2014.08.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/16/2014] [Accepted: 08/23/2014] [Indexed: 01/23/2023]
Abstract
BACKGROUND Classical citrullinemia (CTLN1) is an inborn error of the urea cycle caused by reduced/abolished activity of argininosuccinate synthetase due to mutations in the ASS1 gene. To determine the pathogenicity of novel variants detected in patients is often a huge challenge in molecular diagnosis. The purpose of our study was to characterize novel ASS1 gene mutations identified in CTLN1 patients. METHODS Exon trapping assay with pSPL3 was used to confirm splice aberrations while bioinformatics structural analysis predicted the possible effects of missense mutations. RESULTS Novel donor site (c.174+1G>A) and missense (p.V141G) mutations were detected in a patient exhibiting a biochemical phenotype only. The splice mutation provoked exon skipping hence the truncated product. The mutation p.V141G, is predicted to disturb a hydrophobic pocket in the ATP binding domain in the ASS. Both mutations are predicted to lower binding of ATP. The second patient presented with early onset neonatal citrullinemia marked by an elevated biochemical profile and a clinical phenotype. Analysis revealed a donor site (c.773+1G>A) mutation leading to both exon skipping and intron retention. Subsequent introduction of premature stop codons would result in severely truncated products likely to be degraded. A previously reported R265C is predicted to distort the citrulline binding site. CONCLUSIONS Three novel mutations are reported in this study. They expand the spectrum of genetic pathology underlying CTLN1. Overall this study provides new insight of CTLN1 and illustrates a comprehensive protocol investigating inborn errors of metabolism at the molecular level.
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Hui E, Yeung MCW, Cheung PT, Kwan E, Low L, Tan KCB, Lam KSL, Chan AOK. The clinical significance of aldosterone synthase deficiency: report of a novel mutation in the CYP11B2 gene. BMC Endocr Disord 2014; 14:29. [PMID: 24694176 PMCID: PMC3976226 DOI: 10.1186/1472-6823-14-29] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/31/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aldosterone synthase (CYP11B2) deficiency is a rare autosomal recessive disorder, usually presenting with severe salt-wasting in infancy or stress-induced hyperkalaemia and postural hypotension in adulthood. Neonatal screening for congenital adrenal hyperplasia, another cause of salt wasting, using 17-hydroxyprogesterone measurement would fail to detect aldosterone synthase deficiency, a diagnosis which may be missed until the patient presents with salt-wasting crisis. Due to this potential life-threatening risk, comprehensive hormonal investigation followed by genetic confirmation for suspected patients would facilitate clinical management of the patient and assessment of the genetic implication in their offspring. CASE PRESENTATION We describe a 33-year old Chinese man who presented in infancy with life-threatening hyponatraemia and failure to thrive, but remained asymptomatic on fludrocortisone since. Chromosomal analysis confirmed a normal male karyotype of 46, XY. Plasma steroid profile showed high plasma renin activity, low aldosterone level, and elevated 18-hydroxycorticosterone, compatible with type 2 aldosterone synthase deficiency. The patient was heterozygous for a novel CYP11B2 mutation: c.977C > A (p.Thr326Lys) in exon 3. He also carried a heterozygous mutation c.523_525delAAG (p.Lys175del) in exon 6, a known pathogenic mutation causing aldosterone synthase deficiency. Sequencing of CYP11B2 in his parents demonstrated that the mother was heterozygous for c.977C > A, and the father was heterozygous for c.523_525delAAG. CONCLUSION Although a rare cause of hyperreninaemic hypoaldosteronism, aldosterone synthase deficiency should be suspected and the diagnosis sought in patients who present with life-threatening salt-wasting in infancy, as it has a good long-term prognosis when adequate fludrocortisone replacement is instituted. To our knowledge, this is the first Chinese patient in which the molecular basis of aldosterone synthase deficiency has been identified.
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Affiliation(s)
- Elaine Hui
- Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Matthew CW Yeung
- Department of Pathology, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Pik To Cheung
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Elaine Kwan
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Louis Low
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Kathryn CB Tan
- Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Karen SL Lam
- Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
| | - Angel OK Chan
- Department of Pathology, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Pokfulam, Hong Kong
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Stefl S, Nishi H, Petukh M, Panchenko AR, Alexov E. Molecular mechanisms of disease-causing missense mutations. J Mol Biol 2013; 425:3919-36. [PMID: 23871686 DOI: 10.1016/j.jmb.2013.07.014] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/04/2013] [Accepted: 07/10/2013] [Indexed: 12/23/2022]
Abstract
Genetic variations resulting in a change of amino acid sequence can have a dramatic effect on stability, hydrogen bond network, conformational dynamics, activity and many other physiologically important properties of proteins. The substitutions of only one residue in a protein sequence, so-called missense mutations, can be related to many pathological conditions and may influence susceptibility to disease and drug treatment. The plausible effects of missense mutations range from affecting the macromolecular stability to perturbing macromolecular interactions and cellular localization. Here we review the individual cases and genome-wide studies that illustrate the association between missense mutations and diseases. In addition, we emphasize that the molecular mechanisms of effects of mutations should be revealed in order to understand the disease origin. Finally, we report the current state-of-the-art methodologies that predict the effects of mutations on protein stability, the hydrogen bond network, pH dependence, conformational dynamics and protein function.
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Affiliation(s)
- Shannon Stefl
- Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634, USA
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12
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Abstract
The cytochrome P450 superfamily consists of a large number of heme-containing monooxygenases. Many human P450s metabolize drugs used to treat human diseases. Others are necessary for synthesis of endogenous compounds essential for human physiology. In some instances, alterations in specific P450s affect the biological processes that they mediate and lead to a disease. In this minireview, we describe medically significant human P450s (from families 2, 4, 7, 11, 17, 19, 21, 24, 27, 46, and 51) and the diseases associated with these P450s.
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Affiliation(s)
- Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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13
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Hobler A, Kagawa N, Hutter MC, Hartmann MF, Wudy SA, Hannemann F, Bernhardt R. Human aldosterone synthase: recombinant expression in E. coli and purification enables a detailed biochemical analysis of the protein on the molecular level. J Steroid Biochem Mol Biol 2012; 132:57-65. [PMID: 22446688 DOI: 10.1016/j.jsbmb.2012.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/06/2012] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
Abstract
Aldosterone, the most important human mineralocorticoid, is involved in the regulation of the blood pressure and has been reported to play a key role in the formation of arterial hypertension, heart failure and myocardial fibrosis. Aldosterone synthase (CYP11B2) catalyzes the biosynthesis of aldosterone by successive 11β- and 18-hydroxylation followed by an 18-oxidation of 11-deoxycorticosterone and thus comprises an important drug target. For more than 20 years, all attempts to purify recombinant human CYP11B2 in significant amounts for detailed analysis failed due to its hydrophobic nature as a membrane protein. Here, we present the successful expression of the protein in E. coli yielding approx. 90 nmol/l culture, its purification and detailed enzymatic characterization. Biochemical analyses have been performed using in vitro conversion assays which revelead a V(max) of 238±8 nmol products/nmol hCYP11B2/min and a K(m) of 103±8 μM 11-deoxycorticosterone. Furthermore, binding analyses indicated a very loose binding of the first intermediate of the reaction, corticosterone with a K(d) value of 115±6 μM whereas for 11-deoxycorticosterone a K(d) of 1.34±0.13 μM was estimated. Upon substrate conversion of 11-deoxycorticosterone, new intermediates have been identified as 19- and 18-hydroxylated products not described before for the human enzyme. To understand the differences in substrate conversion, we constructed a new homology model based on the 3D structure of CYP11A1, performed docking studies and calculated the activation energy for hydrogen abstraction of the different ligands. The data demonstrated that the 11β-hydroxylation requires much less abstraction energy than hydroxylation at C18 and C19. However, the C18 and C19 hydroxylated products might be of clinical importance. Finally, purified CYP11B2 represents a suitable tool for the investigation of potential inhibitors of this protein for the development of novel drugs against hypertension and heart failure as was shown using ketoconazole.
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Affiliation(s)
- Anna Hobler
- Department of Biochemistry, Saarland University, 66123 Saarbrücken, Germany
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14
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A case of primary selective hypoaldosteronism carrying three mutations in the aldosterone synthase (Cyp11b2) gene. Gene 2012; 500:22-7. [DOI: 10.1016/j.gene.2012.02.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 01/26/2012] [Accepted: 02/15/2012] [Indexed: 11/21/2022]
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