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Jain G, Das G, Malhotra R, Ramchandran S, Phani NM, Appaswamy G, Sridharan U, Dwivedi A. Hypomagnesemia with Secondary Hypoparathyroidism and Hypocalcemia due to Novel Variants in the Transient Receptor Potential Cation Channel Subfamily M Member 6 ( TRPM6 ) Gene. J Pediatr Genet 2024; 13:35-42. [PMID: 38567178 PMCID: PMC10984712 DOI: 10.1055/s-0041-1733949] [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: 12/28/2020] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
HOMG1 (hypomagnesemia 1, intestinal) or hypomagnesemia with secondary hypocalcemia is a rare autosomal recessive disorder of magnesium metabolism, characterized by impaired magnesium absorption. This disorder may mimic other conditions presenting with neonatal seizures. Here, we report an infant diagnosed to have hypomagnesemia with secondary hypocalcemia due to novel variants in TRPM6 gene.
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Affiliation(s)
| | - Gourab Das
- Army Hospital (Research and Referral), New Delhi, India
| | - Rakhi Malhotra
- Department of Endocrinology, Army Hospital (Research and Referral), New Delhi, Delhi, India
| | - Sateesh Ramchandran
- Department of Endocrinology, Army Hospital (Research and Referral), New Delhi, Delhi, India
| | - Nagaraja M. Phani
- Department of Molecular Genetics, Life cell Diagnostics Pvt. Ltd., India
| | | | | | - Aradhana Dwivedi
- Department of Pediatrics, Division of Clinical Genetics, Army Hospital (Research and Referral), New Delhi, India
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Dokurel Çetin İ, Betül Gerik-Çelebi H, Demiral M, Çetin O. Hereditary hypomagnesemia with secondary hypocalcemia caused by a novel mutation in TRPM6 gene. J Pediatr Endocrinol Metab 2024; 37:184-188. [PMID: 38084506 DOI: 10.1515/jpem-2023-0378] [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: 08/18/2023] [Accepted: 11/27/2023] [Indexed: 02/09/2024]
Abstract
OBJECTIVES Hereditary hypomagnesemia with secondary hypocalcemia (HSH), which results from variations in the transient receptor potential melastatin 6 (TRPM6) genes, is a rare hereditary cause of extremely low serum magnesium levels. We describe an infant with triggered seizures due to hypomagnesemia and a novel mutation in TRPM6 gene was identified. CASE PRESENTATION A 10-month-old boy presented with multidrug resistant seizures, and axial hypotonia due to severe hypomagnesemia. Electroencephalography and neuroimaging of the patient was normal. He had a favorable outcome with magnesium supplement. In this study, the patient underwent clinical exome sequencing (CES) which detected a novel homozygous variant in the TRPM6 gene: NM_017662.5: c.5571-3C>G. After replacing his magnesium orally, he was free from seizures and had an encouraging outcome at the twelfth-month follow-up. CONCLUSIONS HSH often presents with developmental issues, treatment-resistant seizures, and increased neuromuscular excitability. Untreated hypomagnesemia can potentially be fatal and severely impair cognitive function. Clinical suspicion is essential for early diagnosis and treatment.
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Affiliation(s)
- İpek Dokurel Çetin
- Department of Pediatrics, Division of Pediatric Neurology, Balikesir University Medical Faculty, Balikesir, Türkiye
| | | | - Meliha Demiral
- Department of Pediatrics, Division of Pediatric Endocrinology, Ataturk City Hospital, Balikesir, Türkiye
| | - Orkun Çetin
- Department of Obstetrics and Gynecology, Division of Perinatology, Balikesir University Medical Faculty, Balıkesir, Türkiye
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Kamali F, Jamee M, Sayer JA, Sadeghi-Bojd S, Golchehre Z, Dehghanzad R, Keramatipour M, Mohkam M. Intestinal hypomagnesemia in an Iranian patient with a novel TRPM6 variant: a case report and review of the literature. CEN Case Rep 2023; 12:413-418. [PMID: 36967423 PMCID: PMC10620355 DOI: 10.1007/s13730-023-00785-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/13/2023] [Indexed: 03/28/2023] Open
Abstract
TRPM6 is predominantly expressed in the kidney and colon and encodes a protein containing an ion channel domain and a protein kinase domain. It is crucial for magnesium homeostasis and plays important roles in epithelial magnesium transport and the active magnesium absorption. In this study, we present a 70-day-old Iranian female patient from consanguineous parents with hypomagnesemia and secondary hypocalcemia. She presented with seizures 19 days after birth and refractory watery non-bloody diarrhea. She consequently had failure to thrive. Other features included hypotonia, wide anterior fontanel, ventriculomegaly, and pseudotumor cerebri following administration of nalidixic acid. She had severe hypomagnesemia and hypocalcemia which were treated with magnesium and calcium supplementation. Despite initial unstable response to supplemental magnesium, she eventually improved and the diarrhea discontinued. The patient was discharged by magnesium and calcium therapy. At the last follow-up at age 2.5 years, the patient remained well without any recurrence or complication. Genetic testing by whole-exome sequencing revealed a novel homozygous frameshift insertion-deletion (indel) variant in exon 26 of the TRPM6 gene, c.3693-3699del GCAAGAG ins CTGCTGTTGACATCTGCT, p.L1231Ffs*36. Segregation analysis revealed the TRPM6 heterozygous variant in both parents. Patients with biallelic TRPM6 pathogenic variants typically exhibit hypomagnesemia with secondary hypocalcemia and present with neurologic manifestations including seizures. In some patients, this is also complicated by chronic diarrhea and failure to thrive. Long-term complications are rare and most of the patients show a good prognosis with supplemental magnesium therapy.
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Affiliation(s)
- Farnaz Kamali
- Pediatric Nephrology Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Alborz University of Medical Sciences, Karaj, Iran
| | - Mahnaz Jamee
- Pediatric Nephrology Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, NE1 3BZ, UK
- Renal Services, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, NE7 7DN, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle University, Newcastle Upon Tyne, NE45PL, Tyne and Wear, UK
| | - Simin Sadeghi-Bojd
- Genetics of Non-Communicable Disease Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Zahra Golchehre
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Reyhaneh Dehghanzad
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Keramatipour
- Watson Genetic Laboratory, North Kargar Street, Tehran, Iran.
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Masoumeh Mohkam
- Pediatric Nephrology Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Han Y, Zhao Y, Wang H, Huo L. Case Report: Novel TRPM6 Mutations Cause Hereditary Hypomagnesemia With Secondary Hypocalcemia in a Chinese Family and a Literature Review. Front Pediatr 2022; 10:912524. [PMID: 35903165 PMCID: PMC9315244 DOI: 10.3389/fped.2022.912524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hereditary hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease due to biallelic TRPM6 mutations. Although the reports of HSH caused by TRPM6 mutations are not very rare, the age of onset in previously reported HSH cases were <1 year. METHODS We collected and analyzed the clinical data of twin brothers with onset age over 1 year old and performed whole exome sequencing in the patients and their parents. Confirmed by Sanger sequencing, missense mutation was analyzed in silico. We also searched Pubmed, and extracted clinical data from case reports and case series with full text in English, reporting original data of patients with TRPM6 mutations. RESULTS The twin patients had canonical HSH phenotype with compound novel TRPM6 mutations, p.T87K and c.705dupT, inherited from their father and mother, respectively. T87 is a highly conserved site and T87K is predicted to cause hydrogen bond disruption. We identified 26 articles published between May 28, 2002 to December 31, 2021 which reported a total of 88 patients with TRPM6 mutation. We found that the most common clinical phenotypes were hypomagnesemia, hypocalcemia, and convulsions. However, the age of onset in HSH patients almost always occurred under 12 months old, the twin patients of our study were 18 and 26 months old at onset. CONCLUSION We identified two novel TRPM6 mutations in a Chinses family with HSH, and showed that the age of onset with c.704c-c.705(exon7)insT and c.260(exon4)C>A mutation in TRPM6 was much later than other mutations and would be much less serious.
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Affiliation(s)
- Yiran Han
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yajuan Zhao
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Hua Wang
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Liang Huo
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
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Acar S, Schlingmann KP, Nalbantoğlu Ö, Köprülü Ö, Arslan G, Özkaya B, Özkan B. A novel synonymous homozygous variant [c.2538G>A (p.Thr846Thr)] in TRPM6 in a patient with hypomagnesemia with secondary hypocalcemia. J Pediatr Endocrinol Metab 2021; 34:1481-1486. [PMID: 34261199 DOI: 10.1515/jpem-2021-0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/20/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Hypomagnesemia 1, intestinal (HOMG1) is characterized by neurological symptoms that occur due to hypocalcemia and hypomagnesemia and caused by mutations in the TRPM6. Most of the identified variants in TRPM6 lead to premature termination: nonsense, frameshift, deletion, and splice site mutations. CASE PRESENTATION Herein, we report a 1.5 month-old case who presented with convulsion due to hypocalcemia and hypomagnesemia in the early infancy. Sequencing of TRPM6 revealed a novel homozygous synonymous variant [c.2538G > A (p.Thr846Thr)] in the last codon of exon 19, which is most likely to affect the splicing. We report a novel homozygous synonymous variant in the TRPM6 leading to HOMG1, expanding the mutational spectrum. CONCLUSIONS Synonymous mutations that were previously considered as harmless should be evaluated at the nucleotide level, keeping in mind that they may affect splicing and cause to the disease.
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Affiliation(s)
- Sezer Acar
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
| | | | - Özlem Nalbantoğlu
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
| | - Özge Köprülü
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
| | - Gülçin Arslan
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
| | - Beyhan Özkaya
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
| | - Behzat Özkan
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Education and Research Hospital, Izmir, Turkey
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Bayramoğlu E, Keskin M, Aycan Z, Savaş-Erdeve Ş, Çetinkaya S. Long-term Clinical Follow-up of Patients with Familial Hypomagnesemia with Secondary Hypocalcemia. J Clin Res Pediatr Endocrinol 2021; 13:300-307. [PMID: 33565749 PMCID: PMC8388043 DOI: 10.4274/jcrpe.galenos.2021.2020.0192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVE Familial hypomagnesemia with secondary hypocalcemia (HSH) is an autosomal recessive disease caused by a mutation in the transient receptor potential melastatin 6 (TRPM6) gene and is characterized by selective magnesium malabsorption. Affected cases are usually diagnosed during infancy and usually present with seizures due to hypocalcemia and hypomagnesemia. Irreversible neurological deficits and arrhythmias can be observed without appropriate treatment. The aim was to evaluate the long-term follow-up of patients with genetically confirmed HSH. METHODS A total of six patients with HSH, two of whom were siblings, were included. Age at diagnosis, clinical, laboratory and follow-up data on admission were recorded. All 39 exons of the TRPM6 gene and flanking exon-intron junctions from genomic DNA were amplified and sequenced in all cases. RESULTS The median (range) follow-up duration was 12.1 (7.6-21.7) years. All cases were diagnosed in infancy. Four different mutations, three of which had not been previously reported, were detected in the TRPM6 gene. Treatment compliance was good and there were no severe complications in the long-term follow-up of cases. However, mental retardation, specific learning difficulty and attention deficit/hyperactive disorder were observed as comorbidities. CONCLUSION Of the four different TRPM6 mutations in this small cohort, three had not been previously reported. The long-term prognosis of HSH appears to be good, given early diagnosis and good treatment compliance. This long-term follow-up and prognostic data and the three novel mutations will contribute to the published evidence concerning this rare condition, HSH, and it is hoped will prevent negative outcomes.
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Affiliation(s)
- Elvan Bayramoğlu
- University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey,* Address for Correspondence: University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey Phone: +90 312 305 65 13 E-mail:
| | - Melikşah Keskin
- University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Zehra Aycan
- University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Şenay Savaş-Erdeve
- University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Semra Çetinkaya
- University of Health Sciences Turkey, Ankara Dr. Sami Ulus Obstetrics and Gynecology and Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
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Papez J, Starha J, Slaba K, Hubacek JA, Pecl J, Aulicka S, Urik M, Ceylaner S, Vesela P, Slaby O, Jabandziev P. Novel mutations in TRPM6 gene associated with primary hypomagnesemia with secondary hypocalcemia. Case report. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2021; 165:454-457. [PMID: 34012148 DOI: 10.5507/bp.2021.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/22/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Primary hypomagnesemia with secondary hypocalcemia (HSH) is a rare genetic disorder. Dysfunctional transient receptor potential melastatin 6 causes impaired intestinal absorption of magnesium, leading to low serum levels accompanied by hypocalcemia. Typical signs at initial manifestation are generalized seizures, tetany, and/or muscle spasms. CASE REPORT We present a 5 w/o female manifesting tonic-clonic seizures. Laboratory tests detected severe hypomagnesemia and hypocalcemia. The molecular genetic analysis revealed two novel mutations within the TRPM6 gene c.3308dupC (p.Pro1104Thrfs*28) (p.P1104Tfs*28) and c.3958C>T (p.Gln1302*) (p.Q1302*) and the patient was successfully treated with Mg supplementation. CONCLUSION Ion disbalance should be taken into account in the differential diagnosis of infantile seizures. Accurate diagnosis of HSH together with appropriate treatment are crucial to prevent irreversible neurological outcomes.
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Affiliation(s)
- Jan Papez
- Department of Pediatrics, University Hospital Brno, Brno, Czech Republic.,Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jiri Starha
- Department of Pediatrics, University Hospital Brno, Brno, Czech Republic.,Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Katerina Slaba
- Department of Pediatrics, University Hospital Brno, Brno, Czech Republic.,Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jaroslav A Hubacek
- Experimental Medicine Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,3
| | - Jakub Pecl
- Department of Pediatrics, University Hospital Brno, Brno, Czech Republic.,Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Stefania Aulicka
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Department of Pediatric Neurology, University Hospital Brno, Brno, Czech Republic
| | - Milan Urik
- Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | | | - Petra Vesela
- Central European Institute of Technology, Brno, Czech Republic
| | - Ondrej Slaby
- Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology, Brno, Czech Republic.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Petr Jabandziev
- Department of Pediatrics, University Hospital Brno, Brno, Czech Republic.,Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology, Brno, Czech Republic
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Prot-Bertoye C, Houillier P. Claudins in Renal Physiology and Pathology. Genes (Basel) 2020; 11:genes11030290. [PMID: 32164158 PMCID: PMC7140793 DOI: 10.3390/genes11030290] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 12/18/2022] Open
Abstract
Claudins are integral proteins expressed at the tight junctions of epithelial and endothelial cells. In the mammalian kidney, every tubular segment express a specific set of claudins that give to that segment unique properties regarding permeability and selectivity of the paracellular pathway. So far, 3 claudins (10b, 16 and 19) have been causally traced to rare human syndromes: variants of CLDN10b cause HELIX syndrome and variants of CLDN16 or CLDN19 cause familial hypomagnesemia with hypercalciuria and nephrocalcinosis. The review summarizes our current knowledge on the physiology of mammalian tight junctions and paracellular ion transport, as well as on the role of the 3 above-mentioned claudins in health and disease. Claudin 14, although not having been causally linked to any rare renal disease, is also considered, because available evidence suggests that it may interact with claudin 16. Some single-nucleotide polymorphisms of CLDN14 are associated with urinary calcium excretion and/or kidney stones. For each claudin considered, the pattern of expression, the function and the human syndrome caused by pathogenic variants are described.
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Affiliation(s)
- Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- Service de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, F-75015 Paris, France
- CNRS, ERL8228, F-75006 Paris, France
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- Service de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, F-75015 Paris, France
- CNRS, ERL8228, F-75006 Paris, France
- Correspondence:
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Mild hypotonia and recurrent seizures in an 8-month-old boy: Answers. Pediatr Nephrol 2019; 34:1729-1731. [PMID: 30903374 DOI: 10.1007/s00467-019-04236-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 02/10/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
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10
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Taguchi K, Cho SY, Ng AC, Usawachintachit M, Tan YK, Deng YL, Shen CH, Gyawali P, Alenezi H, Basiri A, Bou S, Djojodemedjo T, Sarica K, Shi L, Singam P, Singh SK, Yasui T. The Urological Association of Asia clinical guideline for urinary stone disease. Int J Urol 2019; 26:688-709. [PMID: 31016804 DOI: 10.1111/iju.13957] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 03/04/2019] [Indexed: 12/12/2022]
Abstract
The Urological Association of Asia, consisting of 25 member associations and one affiliated member since its foundation in 1990, has planned to develop Asian guidelines for all urological fields. The field of stone diseases is the third of its guideline projects. Because of the different climates, and social, economic and ethnic environments, the clinical practice for urinary stone diseases widely varies among the Asian countries. The committee members of the Urological Association of Asia on the clinical guidelines for urinary stone disease carried out a surveillance study to better understand the diversity of the treatment strategy among different regions and subsequent systematic literature review through PubMed and MEDLINE database between 1966 and 2017. Levels of evidence and grades of recommendation for each management were decided according to the relevant strategy. Each clinical question and answer were thoroughly reviewed and discussed by all committee members and their colleagues, with suggestions from expert representatives of the American Urological Association and European Association of Urology. However, we focused on the pragmatic care of patients and our own evidence throughout Asia, which included recent surgical trends, such as miniaturized percutaneous nephrolithotomy and endoscopic combined intrarenal surgery. This guideline covers all fields of stone diseases, from etiology to recurrence prevention. Here, we present a short summary of the first version of the guideline - consisting 43 clinical questions - and overview its key practical issues.
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Affiliation(s)
- Kazumi Taguchi
- Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Sung Yong Cho
- Department of Urology, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, Korea.,Seoul National University Hospital, Seoul, Korea
| | - Anthony Cf Ng
- SH Ho Urology Center, Department of Surgery, The Chinese University of Hong Kong, Hong Kong
| | - Manint Usawachintachit
- Division of Urology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand
| | - Yung-Khan Tan
- Urohealth Medical Clinic, Mt Elizabeth Hospital, Singapore
| | - Yao Liang Deng
- Department of Urology, Langdong Hospital and The First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Cheng-Huang Shen
- Department of Urology, Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Prem Gyawali
- Department of Urology, Tribhuvan University Teaching Hospital, Kathmandu, Nepal
| | | | - Abbas Basiri
- Department of Urology, Shahid Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sopheap Bou
- Department of Urology, Royal Phnom Penh Hospital, Phnom Penh, Cambodia
| | - Tarmono Djojodemedjo
- Department of Urology, Soetomo General Academia Hospital/Faculty of Medicine, Airlangga University, Surabaya, Indonesia
| | - Kemal Sarica
- Department of Urology, Kafkas University Medical School, Kars, Turkey
| | - Lei Shi
- Department of Urology, Yantai Yuhuangding Hospital and Medical School, Qingdao University, Yantai, China
| | | | - Shrawan Kumar Singh
- Department of Urology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Takahiro Yasui
- Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Lu J, Zhao X, Paiardini A, Lang Y, Bottillo I, Shao L. Familial hypomagnesaemia, Hypercalciuria and Nephrocalcinosis associated with a novel mutation of the highly conserved leucine residue 116 of Claudin 16 in a Chinese patient with a delayed diagnosis: a case report. BMC Nephrol 2018; 19:181. [PMID: 30005619 PMCID: PMC6045852 DOI: 10.1186/s12882-018-0979-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 06/28/2018] [Indexed: 01/23/2023] Open
Abstract
Background Sixty mutations of claudin 16 coding gene have been reported in familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) patients. Recent investigations revealed that a highly conserved glycine-leucine-tryptophan (115G-L-W117) motif in the first extracellular segment (ESC1) of claudin 16 might be essential for stabilization of the appropriately folded ECS1 structure and conservation of normal claudin 16 function. However, neither missense nor nonsense mutation has ever been described in this motif. Our study aimed at identifying mutations in a Chinese patient with FHHNC and exploring the association between genotype and phenotype. Case presentation A 33-year-old female presented with 4 years history of recurrent acute pyelonephritis without other notable past medical history. Her healthy parents, who aged 56 and 53 respectively, were second cousins, and her only sibling died from renal failure without definite cause at age 25. Renal ultrasound imaging demonstrated atrophic kidneys and bilateral nephrocalcinosis. The laboratory workup revealed impaired renal function (Stage CKD IV), hypocalcemia and mild hypomagnesemia, accompanied with marked renal loss of magnesium and hypercalciuria. During the follow-up, treatment with calcitriol and calcium but not with magnesium was difficult to achieve normal serum calcium levels, whereas her serum magnesium concentration fluctuated within normal ranges. In the end, the patient unavoidably reached ESRD at 36 years old. The clinical features and family history suggested the diagnosis of FHHNC. To make a definite diagnosis, we use whole-exome sequencing to identify the disease-causing mutations and Sanger sequencing to confirm the mutation co-segregation in the family. As a result, a novel homozygous mutation (c.346C > G, p.Leu116Val) in 115G-L-W117 motif of claudin 16 was identified. Her parents, grandmother and one of her cousins carried heterozygous p.Leu116Val, whereas 200 unrelated controls did not carry this mutation. Conclusions We described a delayed diagnosis patient with FHHNC in the Chinese population and identified a novel missense mutation in the highly conserved 115G-L-W117 motif of claudin 16 for the first time. According to the reported data and the information deduced from 3D modeling, we speculate that this mutation probably reserve partial residual function which might be related to the slight phenotype of the patient. Electronic supplementary material The online version of this article (10.1186/s12882-018-0979-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jingru Lu
- Department of Nephrology, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, China.,Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao, 266555, China
| | - Xiangzhong Zhao
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao, 266555, China
| | - Alessandro Paiardini
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza - Università di Roma, 00185, Rome, Italy
| | - Yanhua Lang
- Department of Nephrology, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, China
| | - Irene Bottillo
- Division of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Rome, Italy
| | - Leping Shao
- Department of Nephrology, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, China. .,Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao, 266555, China.
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Patel S, Rayanagoudar G, Gelding S. Familial hypomagnesaemia with secondary hypocalcaemia. BMJ Case Rep 2016; 2016:bcr-2016-216870. [PMID: 27624449 DOI: 10.1136/bcr-2016-216870] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Magnesium is the second most abundant intracellular cation and plays an essential role in neuronal, skeletal and cardiac tissue. Hypomagnesaemia can cause hypocalcaemia by inhibiting parathyroid hormone release and inducing resistance at its receptor sites. Untreated hypomagnesaemia can lead to tetany, recurrent seizures, status epilepticus and life-threatening arrhythmias. Primary hypomagnesaemia with secondary hypocalcaemia (HSH) is a rare metabolic disorder of intestinal magnesium absorption. The condition typically presents in the neonatal period with neuromuscular excitability and seizures refractory to antiepileptic therapy. Early diagnosis and prompt magnesium replacement are essential to prevent death or long-term neurodevelopmental sequelae. Fewer than a hundred cases are reported in the literature. Recent advances have added significantly to our understanding of the genetic basis of HSH. We report the presentation and long-term follow-up of an affected female who was found to have a mutation in the transient receptor potential melastatin 6 (TRPM6) gene, encoding a transient receptor potential cation channel.
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Affiliation(s)
- Sabina Patel
- Department of Endocrinology, Barts Health NHS Trust, London, UK
| | | | - Susan Gelding
- Department of Endocrinology, Barts Health NHS Trust, London, UK
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Altıncık A, Schlingmann KP, Tosun MS. A Novel Homozygous Mutation in the Transient Receptor Potential Melastatin 6 Gene: A Case Report. J Clin Res Pediatr Endocrinol 2016; 8:101-4. [PMID: 26759217 PMCID: PMC4805040 DOI: 10.4274/jcrpe.2254] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Hereditary hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease caused by mutations in the transient receptor potential melastatin 6 (TRPM6) gene. Affected individuals present in early infancy with seizures caused by the severe hypocalcemia and hypomagnesemia. By presenting this case report, we also aimed to highlight the need for molecular genetic analysis in inbred or familial cases with hypomagnesemia. A Turkish inbred girl, now aged six years, had presented to another hospital at age two months with seizures diagnosed to be due to hypomagnesemia. She was on magnesium replacement therapy when she was admitted to our clinic with complaints of chronic diarrhea at age 3.6 years. During her follow-up in our clinic, she showed an age-appropriate physical and neurological development. In molecular genetic analysis, a novel homozygous frame-shift mutation (c.3447delT>p.F1149fs) was identified in the TRPM6 gene. This mutation leads to a truncation of the TRPM6 protein, thereby complete loss of function. We present the clinical follow-up findings of a pediatric HSH case due to a novel mutation in the TRPM6 gene and highlight the need for molecular genetic analysis in inbred or familial cases with hypomagnesemia.
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Affiliation(s)
- Ayça Altıncık
- Denizli State Hospital, Clinic of Pediatric Endocrinology, Denizli, Turkey, E-mail: ,
| | | | - Mahya Sultan Tosun
- Denizli State Hospital, Clinic of Pediatric Gastroenterology, Denizli, Turkey
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15
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Astor MC, Løvås K, Wolff ASB, Nedrebø B, Bratland E, Steen-Johnsen J, Husebye ES. Hypomagnesemia and functional hypoparathyroidism due to novel mutations in the Mg-channel TRPM6. Endocr Connect 2015; 4:215-22. [PMID: 26273099 PMCID: PMC4566842 DOI: 10.1530/ec-15-0066] [Citation(s) in RCA: 18] [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: 07/26/2015] [Accepted: 08/13/2015] [Indexed: 11/26/2022]
Abstract
Primary hypomagnesemia with secondary hypocalcemia (HSH) is an autosomal recessive disorder characterized by neuromuscular symptoms in infancy due to extremely low levels of serum magnesium and moderate to severe hypocalcemia. Homozygous mutations in the magnesium transporter gene transient receptor potential cation channel member 6 (TRPM6) cause the disease. HSH can be misdiagnosed as primary hypoparathyroidism. The aim of this study was to describe the genetic, clinical and biochemical features of patients clinically diagnosed with HSH in a Norwegian cohort. Five patients in four families with clinical features of HSH were identified, including one during a national survey of hypoparathyroidism. The clinical history of the patients and their families were reviewed and gene analyses of TRPM6 performed. Four of five patients presented with generalized seizures in infancy and extremely low levels of serum magnesium accompanied by moderate hypocalcemia. Two of the patients had an older sibling who died in infancy. Four novel mutations and one large deletion in TRPM6 were identified. In one patient two linked homozygous mutations were located in exon 22 (p.F978L) and exon 23 (p.G1042V). Two families had an identical mutation in exon 25 (p.E1155X). The fourth patient had a missense mutation in exon 4 (p.H61N) combined with a large deletion in the C-terminal end of the gene. HSH is a potentially lethal condition that can be misdiagnosed as primary hypoparathyroidism. The diagnosis is easily made if serum magnesium is measured. When treated appropriately with high doses of oral magnesium supplementation, severe hypomagnesemia is uncommon and the long-term prognosis seems to be good.
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Affiliation(s)
- Marianne C Astor
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Kristian Løvås
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Anette S B Wolff
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Bjørn Nedrebø
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Eirik Bratland
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Jon Steen-Johnsen
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
| | - Eystein S Husebye
- Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway Department of Clinical ScienceUniversity of Bergen, Bergen, NorwayDepartment of MedicineHaukeland University Hospital, Bergen, NorwayDepartment of MedicineHaugesund Hospital, Haugesund, NorwayPediatric DepartmentTelemark County Hospital, Skien, Norway
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Claverie-Martin F. Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis: clinical and molecular characteristics. Clin Kidney J 2015; 8:656-64. [PMID: 26613020 PMCID: PMC4655790 DOI: 10.1093/ckj/sfv081] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/04/2015] [Indexed: 01/19/2023] Open
Abstract
Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal-recessive renal tubular disorder characterized by excessive urinary losses of magnesium and calcium, bilateral nephrocalcinosis and progressive chronic renal failure. Presentation with FHHNC symptoms generally occurs early in childhood or before adolescence. At present, the only therapeutic option is supportive and consists of oral magnesium supplementation and thiazide diuretics. However, neither treatment seems to have a significant effect on the levels of serum magnesium or urine calcium or on the decline of renal function. In end-stage renal disease patients, renal transplantation is the only effective approach. This rare disease is caused by mutations in the CLDN16 or CLDN19 genes. Patients with mutations in CLDN19 also present severe ocular abnormalities such as myopia, nystagmus and macular colobamata. CLDN16 and CLDN19 encode the tight-junction proteins claudin-16 and claudin-19, respectively, which are expressed in the thick ascending limb of Henle's loop and form an essential complex for the paracellular reabsorption of magnesium and calcium. Claudin-19 is also expressed in retinal epithelium and peripheral neurons. Research studies using mouse and cell models have generated significant advances on the understanding of the pathophysiology of FHHNC. A recent finding has established that another member of the claudin family, claudin-14, plays a key regulatory role in paracellular cation reabsorption by inhibiting the claudin-16-claudin-19 complex. Furthermore, several studies on the molecular and cellular consequences of disease-causing CLDN16 and CLDN19 mutations have provided critical information for the development of potential therapeutic strategies.
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Affiliation(s)
- Felix Claverie-Martin
- Unidad de Investigación, Hospital Nuestra Señora de Candelaria , Santa Cruz de Tenerife , Spain
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Katayama K, Povalko N, Yatsuga S, Nishioka J, Kakuma T, Matsuishi T, Koga Y. New TRPM6 mutation and management of hypomagnesaemia with secondary hypocalcaemia. Brain Dev 2015; 37:292-8. [PMID: 24985022 DOI: 10.1016/j.braindev.2014.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 06/04/2014] [Accepted: 06/06/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND TRPM6 gene mutation has been reported to cause hypomagnesemia with secondary hypocalcemia (HSH). However, the genotype-phenotype correlation for TRPM6 gene mutations has not been clarified. OBJECTIVE To elucidate the factors underlying the severe neurological complications in HSH and evaluate the potential association between the location of TRPM6 gene mutations and clinical data of HSH. METHODS A Japanese patient diagnosed with HSH at 10 weeks of age exhibited neurological damage and failed to thrive. Magnesium supplements were therefore started at 12 weeks of age. Mutational analysis of the TRPM6 gene was performed using a direct sequencing method to determine the position and type of mutation. Using the data of 29 HSH patients reported in the literature, linear regression analysis was also performed to examine the association between TRPM6 gene mutation location and HSH onset age, initial serum magnesium and calcium concentrations, and dose of oral magnesium. RESULTS A novel stop-codon homozygous mutation [c.4190 G>A] W1397X was identified in exon 26 of the patient's TRPM6 gene. No statistical correlation was found between the location of mutations in the TRPM6 gene and the clinical data for 4 clinical indicators of HSH. CONCLUSIONS We identified the first Japanese HSH patient with a novel nonsense mutation in the TRPM6 gene. Regression analysis of mutation locations in the protein-coding region of TRPM6 and the reported clinical data for 4 clinical indicators of HSH in 30 HSH patients did not detect a genotype-phenotype correlation.
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Affiliation(s)
- Koujyu Katayama
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Nataliya Povalko
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Shuichi Yatsuga
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Junko Nishioka
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Tatsuyuki Kakuma
- Department of Biostatistics, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Toyojiro Matsuishi
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan
| | - Yasutoshi Koga
- Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan.
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Abstract
PURPOSE OF REVIEW The tight control of blood magnesium (Mg) levels is of central importance for numerous physiological processes. A persistent low Mg status (hypomagnesemia) is associated with severe health risks and is involved in the pathogenesis of type 2 diabetes mellitus, osteoporosis, asthma, and heart and vascular diseases. The current view has expanded significantly as a result of the identification of novel genes and regulatory pathways involved in hypomagnesemic disorders. This review aims to give an up-to-date overview of transient receptor potential melastatin 6 (TRPM6) regulation and its role in the maintenance of Mg homeostasis. RECENT FINDINGS The epithelial Mg channel TRPM6 is considered to be the Mg entry pathway in the distal convoluted tubule of the kidney, where it functions as gatekeeper for controlling the body's Mg balance. Various factors and hormones contribute not only to the function, but also to the dysregulation of TRPM6, which has a substantial impact on renal Mg handling. Recent genetic and molecular studies have further elucidated the signaling processes of epithelial Mg transport, including their effect on the expression and function of TRPM6. SUMMARY Knowledge of TRPM6 functioning is of vital importance to decipher its role in Mg handling and will, in particular, provide a molecular basis for achieving a better understanding of Mg mal(re)absorption and hence systemic Mg balance.
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Claverie-Martín F, Vargas-Poussou R, Müller D, García-Nieto V. Clinical utility gene card for: Familial hypomagnesemia with hypercalciuria and nephrocalcinosis with/without severe ocular involvement. Eur J Hum Genet 2014; 23:ejhg2014176. [PMID: 25182135 DOI: 10.1038/ejhg.2014.176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/28/2014] [Accepted: 07/13/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Félix Claverie-Martín
- Unidad de Investigación, Hospital Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | | | - Dominik Müller
- Department of Pediatric Nephrology, Charité, Berlin, Germany
| | - Víctor García-Nieto
- Unidad de Nefrología Pediátrica, Hospital Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
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Abstract
TRPM6 is a bifunctional protein comprising a TRP cation channel segment covalently linked to an α-type serine/threonine protein kinase. TRPM6 is expressed in the intestinal and renal epithelial cells. Loss-of-function mutations in the human TRPM6 gene give rise to hypomagnesemia with secondary hypocalcemia (HSH), suggesting that the TRPM6 channel kinase plays a central role in systemic Mg(2+) homeostasis. In contrast, Trpm6 null mice show a delay in prenatal development, neural tube defects, and prenatal death. Possible functions of TRPM6 in prenatal and adult organisms will be discussed in this chapter.
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Affiliation(s)
- Vladimir Chubanov
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians University Munich, Goethestrasse 33, Munich, 80336, Germany,
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Lainez S, Schlingmann KP, van der Wijst J, Dworniczak B, van Zeeland F, Konrad M, Bindels RJ, Hoenderop JG. New TRPM6 missense mutations linked to hypomagnesemia with secondary hypocalcemia. Eur J Hum Genet 2013; 22:497-504. [PMID: 23942199 DOI: 10.1038/ejhg.2013.178] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 06/20/2013] [Accepted: 07/11/2013] [Indexed: 11/09/2022] Open
Abstract
Despite recent progress in our understanding of renal magnesium (Mg(2+)) handling, the molecular mechanisms accounting for transepithelial Mg(2+) transport are still poorly understood. Mutations in the TRPM6 gene, encoding the epithelial Mg(2+) channel TRPM6 (transient receptor potential melastatin 6), have been proven to be the molecular cause of hypomagnesemia with secondary hypocalcemia (HSH; OMIM 602014). HSH manifests in the newborn period being characterized by very low serum Mg(2+) levels (<0.4 mmol/l) accompanied by low serum calcium (Ca(2+)) concentrations. A proportion of previously described TRPM6 mutations lead to a truncated TRPM6 protein resulting in a complete loss-of-function of the ion channel. In addition, five-point mutations have been previously described. The aim of this study was to complement the current clinical picture by adding the molecular data from five new missense mutations found in five patients with HSH. To this end, patch-clamp analysis and cell surface measurements were performed to assess the effect of the various mutations on TRPM6 channel function. All mutant channels, expressed in HEK293 cells, showed loss-of-function, whereas no severe trafficking impairment to the plasma membrane surface was observed. We conclude that the new TRPM6 missense mutations lead to dysregulated intestinal/renal Mg(2+) (re)absorption as a consequence of loss of TRPM6 channel function.
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Affiliation(s)
- Sergio Lainez
- 1] Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands [2] Department of Pharmacology, University of Cambridge, Cambridge, UK
| | | | - Jenny van der Wijst
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Bernd Dworniczak
- Department of Human Genetics, Westfaelische Wilhelms Universität, Münster, Germany
| | - Femke van Zeeland
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Martin Konrad
- Department of General Pediatrics, University Hospital Münster, Münster, Germany
| | - René J Bindels
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
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Dimke H, Monnens L, Hoenderop JG, Bindels RJ. Evaluation of Hypomagnesemia: Lessons From Disorders of Tubular Transport. Am J Kidney Dis 2013. [DOI: 10.1053/j.ajkd.2012.07.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Affiliation(s)
- Ivana Y Kuo
- Departments of †Pharmacology and ‡Cellular and Molecular Physiology School of Medicine, Yale University , 333 Cedar Street, New Haven, Connecticut 06520
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Farooqi AA, Javeed MK, Javed Z, Riaz AM, Mukhtar S, Minhaj S, Abbas S, Bhatti S. TRPM channels: same ballpark, different players, and different rules in immunogenetics. Immunogenetics 2011; 63:773-87. [PMID: 21932052 DOI: 10.1007/s00251-011-0570-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 09/02/2011] [Indexed: 11/29/2022]
Abstract
Transient receptor potential (TRP) channels belong to a large family of cation channels and are the "border guards" predominantly localized to the plasma membrane. Research over the years has considerably and highly developed the knowledge of expression and functional aspects of the TRPM channels. A closer look at the channel dynamics has dismantled undeniable substantiation for multifaceted roles for TRPM channel-mediated extracellular Ca(2+) influx in several physiological and pathophysiological functions. Given the wealth of literature unfolding the multiple roles of TRP channels in physiology in a very extensive range of different mammalian tissues, this review confines itself to the literature describing the multiple roles of TRPM channels in diabetes, smooth muscle cell regulation, immunological responses, and emerging aspects of cancer. We also focus on differential activities of TRPM channels after post-transcriptional and post-translational processing and their exquisite roles at various cellular and molecular levels.
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Affiliation(s)
- Ammad Ahmad Farooqi
- Institute of Molecular Biology and Biotechnology (IMBB), The University of Lahore, Punjab, Pakistan.
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