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Liu S, Zeng T, Luo C, Peng D, Xu X, Liu Q, Wu Q, Lu Q, Huang F. A rare homozygous variant of MC2R gene identified in a Chinese family with familial glucocorticoid deficiency type 1: A case report. Front Endocrinol (Lausanne) 2023; 14:1113234. [PMID: 36909322 PMCID: PMC10003339 DOI: 10.3389/fendo.2023.1113234] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/08/2023] [Indexed: 02/26/2023] Open
Abstract
Background Melanocortin-2 receptor (MC2R), a member of the G protein-coupled receptor family, is selectively activated by adrenocorticotropic hormone (ACTH). variants in MC2R are associated with family glucocorticoid deficiency 1 (FGD1). Case presentation We first reported a Chinese family with two affected siblings with a homozygotic variant of c.712C>T/p.H238Y in MC2R, presenting with skin hyperpigmentation, hyperbilirubinemia, and tall stature. These individuals showed novel clinical features, including congenital heart defects, not been found in other FGD1 patients. Conclusions We reported a Chinese family with affected siblings having a homozygotic variant of c.712C>T/p.H238Y in MC2R.Our report may expand the genetic and clinical spectrum of FGD1.
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Affiliation(s)
- ShuPing Liu
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Ting Zeng
- Department of Children's Health Care, Liuzhou Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, China
| | - Cheng Luo
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - DanXia Peng
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Xuan Xu
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Qin Liu
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Qiong Wu
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Qin Lu
- Department of Applied and Translational Medicine, GeneMind Biosciences Company Limited, Shenzhen, China
| | - FuRong Huang
- Department of Children’s Medical Center, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
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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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Abuduxikuer K, Li ZD, Xie XB, Li YC, Zhao J, Wang JS. Novel Melanocortin 2 Receptor Variant in a Chinese Infant With Familial Glucocorticoid Deficiency Type 1, Case Report and Review of Literature. Front Endocrinol (Lausanne) 2019; 10:359. [PMID: 31244773 PMCID: PMC6563654 DOI: 10.3389/fendo.2019.00359] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/21/2019] [Indexed: 11/20/2022] Open
Abstract
Familial glucocorticoid deficiency type 1 (FGD1) is an autosomal recessive disorder caused by mutations in the melanocortin 2 receptor (MC2R) gene, characterized by a low or undetectable serum cortisol level and a high adrenocorticotropic hormone (ACTH) level. Clinical manifestations include hypoglycemia, seizure, skin hyperpigmentation, hyperbilirubinemia, cholestasis, and a tall stature. Some dysmorphic features such as, a prominent forehead, hypertelorism, a broad nasal bridge, and small tapering fingers, have been reported. Children with FGD1 may have other isolated endocrine abnormalities. To date, no patient with FGD1 has been reported in mainland China. Here we report on a Chinese patient with FGD1 having a novel MC2R gene variant, a mild transverse palm crease, hypertelorism, and subtle/transient endocrine abnormalities relating to all three zones of the adrenal cortex and thyroid gland. We also reviewed cases with dysmorphic features or additional endocrine abnormalities.
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Fridmanis D, Roga A, Klovins J. ACTH Receptor (MC2R) Specificity: What Do We Know About Underlying Molecular Mechanisms? Front Endocrinol (Lausanne) 2017; 8:13. [PMID: 28220105 PMCID: PMC5292628 DOI: 10.3389/fendo.2017.00013] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/16/2017] [Indexed: 11/13/2022] Open
Abstract
Coincidentally, the release of this Research Topic in Frontiers in Endocrinology takes place 25 years after the discovery of the adrenocorticotropic hormone receptor (ACTHR) by Mountjoy and colleagues. In subsequent years, following the discovery of other types of mammalian melanocortin receptors (MCRs), ACTHR also became known as melanocortin type 2 receptor (MC2R). At present, five types of MCRs have been reported, all of which share significant sequence similarity at the amino acid level, and all of which specifically bind melanocortins (MCs)-a group of biologically active peptides generated by proteolysis of the proopiomelanocortin precursor. All MCs share an identical -H-F-R-W- pharmacophore sequence. α-Melanocyte-stimulating hormone (α-MSH) and adrenocorticotropic hormone (ACTH) are the most extensively studied MCs and are derived from the same region. Essentially, α-MSH is formed from the first 13 amino acid residues of ACTH. ACTHR is unique among MCRs because it binds one sole ligand-ACTH, which makes it a very attractive research object for molecular pharmacologists. However, much research has failed, and functional studies of this receptor are lagging behind other MCRs. The reason for these difficulties has already been outlined by Mountjoy and colleagues in their publication on ACTHR coding sequence discovery where the Cloudman S91 melanoma cell line was used for receptor expression because it was a "more sensitive assay system." Subsequent work showed that ACTHR could be successfully expressed only in endogenous MCR-expressing cell lines, since in other cell lines it is retained within the endoplasmic reticulum. The resolution of this methodological problem came in 2005 with the discovery of melanocortin receptor accessory protein, which is required for the formation of functionally active ACTHR. The decade that followed this discovery was filled with exciting research that provided insight into the molecular mechanisms underlying the action of ACTHR. The purpose of this review is to summarize the advances in this fascinating research field.
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Affiliation(s)
| | - Ance Roga
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Janis Klovins
- Latvian Biomedical Research and Study Centre, Riga, Latvia
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Villanelo F, Escalona Y, Pareja-Barrueto C, Garate JA, Skerrett IM, Perez-Acle T. Accessing gap-junction channel structure-function relationships through molecular modeling and simulations. BMC Cell Biol 2017; 18:5. [PMID: 28124624 PMCID: PMC5267332 DOI: 10.1186/s12860-016-0121-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background Gap junction channels (GJCs) are massive protein channels connecting the cytoplasm of adjacent cells. These channels allow intercellular transfer of molecules up to ~1 kDa, including water, ions and other metabolites. Unveiling structure-function relationships coded into the molecular architecture of these channels is necessary to gain insight on their vast biological function including electrical synapse, inflammation, development and tissular homeostasis. From early works, computational methods have been critical to analyze and interpret experimental observations. Upon the availability of crystallographic structures, molecular modeling and simulations have become a valuable tool to assess structure-function relationships in GJCs. Modeling different connexin isoforms, simulating the transport process, and exploring molecular variants, have provided new hypotheses and out-of-the-box approaches to the study of these important channels. Methods Here, we review foundational structural studies and recent developments on GJCs using molecular modeling and simulation techniques, highlighting the methods and the cross-talk with experimental evidence. Results and discussion By comparing results obtained by molecular modeling and simulations techniques with structural and functional information obtained from both recent literature and structural databases, we provide a critical assesment of structure-function relationships that can be obtained from the junction between theoretical and experimental evidence.
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Affiliation(s)
- F Villanelo
- Computational Biology Lab. Fundación Ciencia & Vida, Santiago, Chile
| | - Y Escalona
- Computational Biology Lab. Fundación Ciencia & Vida, Santiago, Chile
| | - C Pareja-Barrueto
- Computational Biology Lab. Fundación Ciencia & Vida, Santiago, Chile
| | - J A Garate
- Computational Biology Lab. Fundación Ciencia & Vida, Santiago, Chile.,Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - I M Skerrett
- State University of New York (SUNY) Buffalo State, Buffalo, NY, 14222, USA
| | - T Perez-Acle
- Computational Biology Lab. Fundación Ciencia & Vida, Santiago, Chile. .,Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile.
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Overton JD, Leibel RL. Mahoganoid and mahogany mutations rectify the obesity of the yellow mouse by effects on endosomal traffic of MC4R protein. J Biol Chem 2011; 286:18914-29. [PMID: 21460229 DOI: 10.1074/jbc.m111.224592] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ubiquitous overexpression of agouti-signaling protein (ASP), a paracrine-signaling molecule that regulates pigment-type switching in the hair follicle of the mouse, is responsible for the obesity and yellow pelage of the Yellow mouse (A(y)). Mahogany (Attractin, Atrn/mg) and mahoganoid (Mahogunin Ring Finger-1, Mgrn1/md) are mutations epistatic to A(y). These mutations have been described as suppressors of ASP action, blocking its antagonizing effects on the melanocortin 1 and 4 receptors (MC1R and MC4R) in the skin and the brain, respectively, via unknown mechanisms. Here, we describe the molecular bases for the md- and mg-dependent rescue of the A(y) phenotype at the MC4R. We show that overexpression of ASP inhibits the rise in cAMP levels in response to α-melanocyte-stimulating hormone, an MC4R agonist, by blocking ligand binding and by directing MC4R trafficking to the lysosome. Loss-of-function of either attractin or MGRN1 blocks ASP-dependent MC4R degradation and promotes increased trafficking of internalized MC4R to the cell surface, but it does not restore α-melanocyte-stimulating hormone-dependent cAMP signaling. We propose that MGRN1 and attractin are components of an evolutionarily conserved receptor trafficking pathway and that the md and mg mutations rescue the A(y) phenotypes by a primarily cAMP-independent mechanism promoting trafficking of MC4R and likely MC1R away from the lysosome toward the cell surface.
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Affiliation(s)
- John D Overton
- Division of Molecular Genetics, Department of Pediatrics, Naomi Berrie Diabetes Center and the Institute of Human Nutrition, Columbia University, New York, New York 10032, USA.
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Chung TTLL, Chan LF, Metherell LA, Clark AJL. Phenotypic characteristics of familial glucocorticoid deficiency (FGD) type 1 and 2. Clin Endocrinol (Oxf) 2010; 72:589-94. [PMID: 19558534 PMCID: PMC2855830 DOI: 10.1111/j.1365-2265.2009.03663.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
CONTEXT Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disorder as a result of mutation in genes encoding either the ACTH receptor [melanocortin 2 receptor (MC2R)] or its accessory protein [melanocortin 2 receptor accessory protein (MRAP)]. The disorder is known as FGD type 1 and 2, respectively. OBJECTIVE The aim of the study was to compare the phenotype/genotype relationships between FGD 1 and 2. DESIGN AND PATIENTS Forty patients with missense MC2R mutations and 22 patients with MRAP mutations were included. Forty-four of these patients had been referred for genetic screening and 18 were patients published by other authors. RESULTS The median age at presentation for FGD type 1 was variable at 2.0 years; range 0.02-16 years, and this was associated with unusually tall stature, mean height SDS + 1.75 +/- 1.53 (mean +/- SD). In contrast, FGD type 2 presented at a much earlier median age (0.08 years; range at birth to 1.6 years) (P < 0.01) and patients were of normal height SDS + 0.12 +/- 1.35 (P < 0.001). No differences in baseline cortisol or ACTH levels were seen between FGD types 1 and 2. CONCLUSION FGD type 2 appears to present earlier. This may reflect the functional significance of the underlying mutations in that all MRAP mutations are nonsense or splice site mutations that result in abolition of a functional protein, whereas most of the MC2R mutations are missense mutations and give rise to proteins with some residual function. Tall stature is associated with mutations in MC2R but not in MRAP. There were no other significant clinical distinctions between the two.
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Affiliation(s)
- Teng-Teng L L Chung
- Centre for Endocrinology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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Newfield RS. ACTH receptor blockade: A novel approach to treat congenital adrenal hyperplasia, or Cushing’s disease. Med Hypotheses 2010; 74:705-6. [DOI: 10.1016/j.mehy.2009.10.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 10/18/2009] [Indexed: 11/28/2022]
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Elias LLK, Clark AL. The molecular basis of adrenocorticotrophin resistance syndrome. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 88:155-71. [PMID: 20374727 DOI: 10.1016/s1877-1173(09)88005-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Adrenocorticotrophin resistance syndromes comprise familial glucocorticoid deficiency (FGD) and triple A syndrome, which are rare autosomal recessive diseases with distinct clinical features and molecular etiologies. Mutations of melanocortin-2 receptor (MC2R) have been described in segregation with FGD in 25% of patients. More recently melanocortin-2 receptor accessory protein (MRAP), a small single-transmembrane domain protein, was described as an essential protein for the traffic of MC2R and its expression on the plasma membrane. About 20% of FGD patients carry homozygous mutations of MRAP. The ALADIN protein (for alacrima/achalasia/adrenal insufficiency/neurologic disorder) was identified as the molecular basis of triple A syndrome. The elucidation of the genetic basis of the ACTH resistance syndrome has contributed to the better understanding of MC2R function. However, in some patients the molecular etiology is not yet known and awaits further genetic studies.
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Affiliation(s)
- Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Sao Paulo, Brazil
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2009; 16:260-77. [PMID: 19390324 DOI: 10.1097/med.0b013e32832c937e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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