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Kardas Yildiz A, Bulbul A, Ozer Bekmez B, Turkyilmaz A, Terali K, Dagdeviren Cakir A, Ucar A. A Rare Presentation of Homozygous Pathogenic Variant in MC2R Gene with Salt-Wasting Crisis in a Neonate. Mol Syndromol 2024; 15:77-82. [PMID: 38357256 PMCID: PMC10862318 DOI: 10.1159/000533986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 09/02/2023] [Indexed: 02/16/2024] Open
Abstract
Introduction Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease resulting from isolated glucocorticoid deficiency or unresponsiveness to adrenocorticotropic hormone. Patients with FGD usually present in infancy or early childhood with hyperpigmentation, recurrent infections, and hypoglycemia. The salt-wasting crisis is rare. Case Presentation A term female neonate was admitted to the neonatal intensive care unit due to respiratory distress. On physical examination, she had generalized hyperpigmentation. Initial laboratory work-up yielded normal serum electrolytes and glucose. Hyponatremia and hyperkalemia emerged on follow-up. The patient was diagnosed as having primary adrenal insufficiency (PAI) with elevated plasma adrenocorticotropin hormone and reduced cortisol levels and hydrocortisone. We started on oral sodium (5 mEq/kg/day) and fludrocortisone (FC) (0.2 mg/day) treatment to the patient. Ultrasonography revealed hypoplastic adrenal glands. Molecular genetic analysis revealed a previously reported homozygous pathogenic variant NM_000529.2: c.560delT (p.V187fs*29) in the MC2R gene. FC dose was tapered to 0.05 mg/day on the third month of life and was stopped at tenth months of age with maintenance of normal serum electrolytes and clinical findings. Conclusion FGD due to MC2R gene mutation may rarely present with a salt-wasting crisis in the neonatal period. Identifying the causative gene with the pathogenic variant in PAI may serve to individualize a treatment plan.
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Affiliation(s)
- Aysenur Kardas Yildiz
- Department of Pediatrics, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ali Bulbul
- Department of Neonatology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Buse Ozer Bekmez
- Department of Neonatology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ayberk Turkyilmaz
- Department of Medical Genetics, Karadeniz Technical University Faculty of Medicine, Trabzon, Turkey
| | - Kerem Terali
- Department of Medical Biochemistry, Cyprus International University Faculty of Medicine, Nicosia, Cyprus
| | - Aydilek Dagdeviren Cakir
- Department of Pediatric Endocrinology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Ucar
- Department of Pediatric Endocrinology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
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Maharaj AV. Familial Glucocorticoid Deficiency: the changing landscape of an eponymous syndrome. Front Endocrinol (Lausanne) 2023; 14:1268345. [PMID: 38189052 PMCID: PMC10771341 DOI: 10.3389/fendo.2023.1268345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/28/2023] [Indexed: 01/09/2024] Open
Abstract
Familial Glucocorticoid Deficiency encompasses a broad spectrum of monogenic recessive disorders that theoretically solely abrogate cortisol biosynthesis. In reality, delineating clear genotype-phenotype correlations in this disorder is made complicated by marked phenotypic heterogeneity even within kindreds harbouring identical variants. Phenotypes range from isolated glucocorticoid insufficiency to cortisol deficiency plus a variety of superimposed features including salt-wasting and hypoaldosteronism, primary hypothyroidism, hypogonadism and growth defects. Furthermore, mutation type, domain topology and perceived enzyme activity do not always predict disease severity. Given the high burden of disease and implications of a positive diagnosis, genetic testing is crucial in the management of patients warranting detailed delineation of genomic variants including viable functional studies.
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Affiliation(s)
- Avinaash V. Maharaj
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London (QMUL), London, United Kingdom
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Duan Y, Xia Y, Gong Z, Liu H, Liang L, Zhang K, Yang Y, Wang R, Xiao B, Qiu W. A Novel Mutation in Melanocortin Receptor 2 and a Reported Mutation in Melanocortin Receptor 2 Accessory Protein: Three Chinese Cases with Familial Glucocorticoid Deficiency. Mol Syndromol 2023; 14:71-79. [PMID: 36777708 PMCID: PMC9911991 DOI: 10.1159/000526320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 07/31/2022] [Indexed: 11/19/2022] Open
Abstract
Background Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease characterized by glucocorticoid deficiency without mineralocorticoid deficiency. We report 3 Chinese patients with MRAP or MC2R mutations. Case Reports Patient 1 presented with hyperpigmentation. Endocrine investigations revealed low serum cortisol levels and elevated adrenocorticotropic hormone (ACTH) levels. Furthermore, low serum sodium was evident. She was diagnosed with FGD type 2 due to a homozygous mutation in MRAP (c.106+1delG), revealed through exome sequencing (ES). After 2-year treatment with hydrocortisone, skin hyperpigmentation was improved. Patient 2 initially presented with hyponatremia. Low cortisol levels and high levels of ACTH were subsequently detected; he was subjected to a hydrocortisone treatment during which he experienced repeated hypoglycemic attacks and pigmentation. ES revealed the same mutation as in patient 1 in MRAP (c.106+1delG), thus he was diagnosed with FGD type 2. After 6 years of age, his symptoms remarkably improved, and there was no episode of hypoglycemia. Patient 3 mainly presented with hyperpigmentation, hypoglycemic attack, and tall stature. Laboratory findings were normal except for low serum cortisol levels and high ACTH levels. She was diagnosed with FGD type 1 as ES revealed a novel homozygous mutation in MC2R (c.712C>A, p.His238Tyr). After nearly 2 years of hydrocortisone replacement therapy, the excessive growth was reduced to near normal, and the skin color returned to normal. Conclusions Three patients were diagnosed with FGD (one with FGD type 1 and two with FGD type 2). They all presented with hyperpigmentation and hypoglycemia; however, compared with patient 1, the clinical manifestations of patient 2 were more complicated. Patient 3 had later onset and taller stature than patients 1 and 2. A novel mutation in patient 3 expands the mutation spectrum of MC2R.
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Luo P, Feng W, Ma S, Dai A, Wu K, Chen X, Yuan Q, Cai X, Yang D, Wang MW, Eric Xu H, Jiang Y. Structural basis of signaling regulation of the human melanocortin-2 receptor by MRAP1. Cell Res 2023; 33:46-54. [PMID: 36588120 PMCID: PMC9810661 DOI: 10.1038/s41422-022-00751-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/08/2022] [Indexed: 01/03/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are regulated by various downstream proteins, of which the melanocortin receptor accessory protein 1 (MRAP1) is closely involved in the regulation of melanocortin receptor 2 (MC2R). Assisted by MRAP1, MC2R responds to adrenocorticotropic hormone (ACTH) and stimulates glucocorticoid biogenesis and cortisol secretion. MC2R activation plays an essential role in the hypothalamic-pituitary-adrenal (HPA) axis that regulates stress response, while its dysfunction causes glucocorticoid insufficiency- or cortisol excess-associated disorders. Here, we present a cryo-electron microscopy (cryo-EM) structure of the ACTH-bound MC2R-Gs-MRAP1 complex. Our structure, together with mutagenesis analysis, reveals a unique sharp kink at the extracellular region of MRAP1 and the 'seat-belt' effect of MRAP1 on stabilizing ACTH binding and MC2R activation. Mechanisms of ACTH recognition by MC2R and receptor activation are also demonstrated. These findings deepen our understanding of GPCR regulation by accessory proteins and provide valuable insights into the ab initio design of therapeutic agents targeting MC2R.
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Affiliation(s)
- Ping Luo
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenbo Feng
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shanshan Ma
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Antao Dai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kai Wu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xianyue Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Qingning Yuan
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoqing Cai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Dehua Yang
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - H Eric Xu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Yi Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Lingang Laboratory, Shanghai, China.
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An Update on Genetics of Adrenal Gland and Associated Disorders. ENDOCRINES 2022. [DOI: 10.3390/endocrines3020017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The intricacies of human adrenal development have been under scrutiny for decades. Each year marks the identification of new genes and new interactions between gene products that ultimately will act to produce the fully functioning adult gland. Due to the complexity of this process, genetic missteps may lead to a constellation of pathologies. Recent years have identified several novel genetic causes of adrenal dysgenesis and provided new insights into previously delineated processes. SF1, DAX1 (NR0B1), CDKN1C, SAMD9, GLI3, TPIT, MC2R, MRAP, NNT, TXNRD2, AAAS, and MCM4 are among the genes which have had significant contributions to our understanding of the development and function of both adrenals and gonads. Collection and elucidation of these genetic and clinical insights are valuable tools for clinicians who diagnose and manage cases of adrenal dysfunction.
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Mohammed I, Haris B, Hussain K. A Novel Homozygous MC2R Variant Leading to Type-1 Familial Glucocorticoid Deficiency. J Endocr Soc 2022; 6:bvac058. [PMID: 35506146 PMCID: PMC9049112 DOI: 10.1210/jendso/bvac058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Indexed: 11/30/2022] Open
Abstract
Context Type 1 familial glucocorticoid deficiency (FGD) (OMIM #607397) is a rare autosomal recessive disorder due to mutations in melanocortin-2-receptor (MC2R) gene encoding the G protein-coupled adrenocorticotropic (ACTH) transmembrane receptor. Objective The aim of the study is to describe 2 siblings born to a healthy consanguineous family presenting with clinical and biochemical features of FGD, harboring a novel homozygous MC2R variant. Methods Both patients are siblings born at term via normal delivery with normal birth weights. The first sibling presented with symptoms of hypoglycemia, repeated episodes of infections starting from 2 days of age. At 18 months of age, low serum cortisol was found, and he was started on hydrocortisone replacement therapy. The second sibling developed hypoglycemia on day 1 after birth, investigations revealed low serum sodium and cortisol levels and was also commenced on hydrocortisone treatment. Whole exome sequencing (WES) and in vitro functional studies on cell line transfected with wild-type and mutant plasmid clones were undertaken. Results WES revealed a novel homozygous missense mutation c.326T>A, p.Leu109Gln in the MC2R gene. In-silico prediction tools predicted the effect of this mutation to be deleterious. In vitro study using HEK293 cells transfected with MC2R wild-type and mutant clones showed a defect in protein expression and cAMP generation when stimulated with ACTH. Conclusion Homozygous semiconserved p.Leu109Gln mutation disrupts cAMP production and MC2R protein expression leading to ACTH resistance. This study provides additional evidence that this novel pathogenic variant in MC2R results in FGD phenotypes.
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Affiliation(s)
- Idris Mohammed
- Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar
- College of Health & Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Basma Haris
- Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar
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