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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: 1] [Impact Index Per Article: 0.5] [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: 5] [Impact Index Per Article: 1.7] [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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Yücel H, Genç Sel Ç, Kasapkara ÇS, Karacan Küçükali G, Savas-Erdeve S, Öztoprak Ü, Ceylaner S, Şenel S, Akçaboy M. Treatment Difficulties in Hypomagnesemia Secondary to the Transient Receptor Potential Melastatin 6 Gene: A Case Report with Novel Mutation. J Clin Res Pediatr Endocrinol 2021; 13:114-118. [PMID: 32302086 PMCID: PMC7947728 DOI: 10.4274/jcrpe.galenos.2020.2020.0004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hypomagnesemia is a rare cause of seizures in childhood but should be kept in mind in recurrent and intractable seizures and hypocalcemia in communities where consanguineous marriages are common. Familial hypomagnesemia with secondary hypocalcemia is a rare genetic cause of hypomagnesemia, due to variants in the transient receptor potential melastatin 6 (TRPM6) genes. Here, a three year-old boy with a novel variant in this gene and had difficulties with enteral hypomagnesemia treatment is presented. He had recurrent seizures since two years of age and was diagnosed with epilepsy and treated with multiple antiepileptic drugs. Subsequently, he was diagnosed with rickets due to severe hypocalcemia at another center. The patient was hypotonic and neurodevelopmentally poor. The most prominent laboratory finding was of hypomagnesemia with secondary hypocalcemia. The genetic analysis revealed a novel variant in the TRPM6 gene. After parental treatment of intravenous magnesium (Mg2+) sulfate and calcium, the treatment was switched to enteral Mg2+ medications, due to persistent hypomagnesemia and the gastrointestinal side-effects, different oral preparations were used. The patient was stable on an oral maintenance dose of Mg2+ oxide with borderline blood Mg2+ levels and resolution of hypocalcemia. Hypomagnesemia is one of the causes of hypocalcemia. Enteral replacement is the key treatment but the treatment should be individualized for each patient. Normalization of hypomagnesemia is not always easy and should not be the aim of the treatment.
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Affiliation(s)
- Hüsniye Yücel
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatrics, Ankara, Turkey
| | - Çiğdem Genç Sel
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatric Neurology, Ankara, Turkey
| | - Çiğdem Seher Kasapkara
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatric Metabolism, Ankara, Turkey
| | - Gülin Karacan Küçükali
- Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Senay Savas-Erdeve
- Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Ülkühan Öztoprak
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatric Neurology, Ankara, Turkey
| | | | - Saliha Şenel
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatrics, Ankara, Turkey
| | - Meltem Akçaboy
- Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatrics, Ankara, Turkey,* Address for Correspondence: Dr. Sami Ulus Maternity and Children’s Health and Diseases Training and Research Hospital, Clinic of Pediatrics, Ankara, Turkey Phone: +90 312 305 60 00 E-mail:
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