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Zheng Z, Wu Y, Wu H, Jin J, Luo Y, Cao S, Shan X. Clinical heterogeneity and therapeutic options for idiopathic infantile hypercalcemia caused by CYP24A1 pathogenic variant. J Pediatr Endocrinol Metab 2023; 36:999-1011. [PMID: 37768904 DOI: 10.1515/jpem-2023-0147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/12/2023] [Indexed: 09/30/2023]
Abstract
OBJECTIVES Infantile hypercalcemia-1 (HCINF1) is a rare disease caused by pathogenic variants in the CYP24A1 gene, resulting in the inability to metabolize active vitamin D. This leads to hypercalcemia and severe complications. CONTENT On December 8th, 2022, a systematic literature search was conducted in PubMed, Wanfang, and CNKI using the keywords "hypercalcemia" and "CYP24A1". Data extraction included patient demographics, clinical presentation, treatment medications, and outcomes. The findings were synthesized to identify common patterns and variations among cases and to assess the efficacy of different therapies in reducing serum calcium. Our findings revealed two distinct peaks in the incidence of HCINF1 caused by CYP24A1 pathogenic variant. Kidney stones or renal calcifications were the most common clinical manifestations of the disease, followed by polyuria and developmental delay. Laboratory investigations showed hypercalcemia, elevated vitamin D levels, hypercalciuria, and low parathyroid hormone. Genetic analysis remains the only reliable diagnostic tool. Although there is no definitive cure for HCINF1, multiple drugs, including bisphosphonates, calcitonin, and rifampicin, have been used to control its symptoms. Blocking the production and intake of vitamin D is the preferred treatment option. SUMMARY AND OUTLOOK Our review highlights the basic clinical and biochemical features of HCINF1 and suggests that targeted diagnostic and therapeutic strategies are needed to address the clinical heterogeneity of the disease. The insights gained from this study may facilitate the development of innovative treatments for HCINF1.
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Affiliation(s)
- Zhichao Zheng
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Yujie Wu
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Huiping Wu
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Jiahui Jin
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Yue Luo
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Shunshun Cao
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Xiaoou Shan
- Department of Pediatric Endocrinology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
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Hypercalcemia in Pregnancy Due to CYP24A1 Mutations: Case Report and Review of the Literature. Nutrients 2022; 14:nu14122518. [PMID: 35745247 PMCID: PMC9229801 DOI: 10.3390/nu14122518] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 02/06/2023] Open
Abstract
Pathogenic mutations of CYP24A1 lead to an impaired catabolism of vitamin D metabolites and should be considered in the differential diagnosis of hypercalcemia with low parathyroid hormone concentrations. Diagnosis is based on a reduced 24,25-dihydroxyvitamin D to 25-hydroxyvitamin D ratio and confirmed by genetic analyses. Pregnancy is associated with an upregulation of the active vitamin D hormone calcitriol and may thus particularly trigger hypercalcemia in affected patients. We present a case report and a narrative review of pregnant women with CYP24A1 mutations (13 women with 29 pregnancies) outlining the laboratory and clinical characteristics during pregnancy and postpartum and the applied treatment approaches. In general, pregnancy triggered hypercalcemia in the affected women and obstetric complications were frequently reported. Conclusions on drugs to treat hypercalcemia during pregnancy are extremely limited and do not show clear evidence of efficacy. Strictly avoiding vitamin D supplementation seems to be effective in preventing or reducing the degree of hypercalcemia. Our case of a 24-year-old woman who presented with hypercalcemia in the 24th gestational week delivered a healthy baby and hypercalcemia resolved while breastfeeding. Pathogenic mutations of CYP24A1 mutations are rare but should be considered in the context of vitamin D supplementation during pregnancy.
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Abstract
Hypercalcemic disorders are rare in pregnant women and are usually due to primary hyperparathyroidism. Clinical manifestations of hypercalcemia are nonspecific and can be masked by the physiologic changes of pregnancy. Furthermore, routine antenatal screening does not include serum calcium measurement and a hypercalcemia diagnosis may therefore be delayed until term or even after delivery. Timely recognition and appropriate interventions are essential to decrease maternal and fetal complications. Conservative measures are appropriate in the presence of mild hypercalcemia. Parathyroidectomy remains the mainstay of treatment for primary hyperparathyroidism with significant hypercalcemia not responding to conservative measures.
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Affiliation(s)
- Karel Dandurand
- Division of Endocrinology and Metabolism, McMaster University, Bone Research and Education Centre, 3075 Hospital Gate, Unit 223, Oakville, ON L6M 1M1, Canada
| | - Dalal S Ali
- Division of Endocrinology and Metabolism, McMaster University, Bone Research and Education Centre, 3075 Hospital Gate, Unit 223, Oakville, ON L6M 1M1, Canada
| | - Aliya A Khan
- Division of Endocrinology and Metabolism, McMaster University, Bone Research and Education Centre, 3075 Hospital Gate, Unit 223, Oakville, ON L6M 1M1, Canada.
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Abstract
Vitamin D metabolism represents a well-integrated, hormonally regulated endocrine unit interlinking calcium and phosphate metabolism. Pathophysiologic processes disturbing vitamin D metabolism comprise classic defects of vitamin D activation and action presenting as different forms of vitamin D-dependent rickets as well as disorders with increased vitamin D activity. The latter may result in hypercalcemia, hypercalciuria, and renal calcifications. Acquired and hereditary disorders causing hypervitaminosis D are discussed, including vitamin D intoxication, granulomatous disease, and idiopathic infantile hypercalcemia that may be caused by either a defective vitamin D degradation or by a primary defect in phosphate conservation.
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Affiliation(s)
- Karl Peter Schlingmann
- Department of General Pediatrics, University Children's Hospital, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
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5
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Lenherr-Taube N, Young EJ, Furman M, Elia Y, Assor E, Chitayat D, Uster T, Kirwin S, Robbins K, Vinette KMB, Daneman A, Marshall CR, Collins C, Thummel K, Sochett E, Levine MA. Mild Idiopathic Infantile Hypercalcemia-Part 1: Biochemical and Genetic Findings. J Clin Endocrinol Metab 2021; 106:2915-2937. [PMID: 34125233 PMCID: PMC8475208 DOI: 10.1210/clinem/dgab431] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Idiopathic infantile hypercalcemia (IIH), an uncommon disorder characterized by elevated serum concentrations of 1,25 dihydroxyvitamin D (1,25(OH)2D) and low parathyroid hormone (PTH) levels, may present with mild to severe hypercalcemia during the first months of life. Biallelic variants in the CYP24A1 or SLC34A1 genes are associated with severe IIH. Little is known about milder forms. OBJECTIVE This work aims to characterize the genetic associations and biochemical profile of mild IIH. METHODS This is a cross-sectional study including children between age 6 months and 17 years with IIH who were followed in the Calcium Clinic at the Hospital for Sick Children (SickKids), Toronto, Canada. Twenty children with mild IIH on calcium-restricted diets were evaluated. We performed a dietary assessment and analyzed biochemical measures including vitamin D metabolites and performed a stepwise molecular genetic analysis. Complementary biochemical assessments and renal ultrasounds were offered to first-degree family members of positive probands. RESULTS The median age was 16 months. Median serum levels of calcium (2.69 mmol/L), urinary calcium:creatinine ratio (0.72 mmol/mmol), and 1,25(OH)2D (209 pmol/L) were elevated, whereas intact PTH was low normal (22.5 ng/L). Mean 1,25(OH)2D/PTH and 1,25(OH)2D/25(OH)D ratios were increased by comparison to healthy controls. Eleven individuals (55%) had renal calcification. Genetic variants were common (65%), with the majority being heterozygous variants in SLC34A1 and SLC34A3, while a minority showed variants of CYP24A1 and other genes related to hypercalciuria. CONCLUSION The milder form of IIH has a distinctive vitamin D metabolite profile and is primarily associated with heterozygous SLC34A1 and SLC34A3 variants.
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Affiliation(s)
- Nina Lenherr-Taube
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Edwin J Young
- Genome Diagnostics, Department of Paediatric Medicine, The Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada
| | - Michelle Furman
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Yesmino Elia
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Esther Assor
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - David Chitayat
- Department of Obstetrics and Gynecology, The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
- Department of Pediatrics, Division of Clinical Genetics and Metabolism, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Tami Uster
- Department of Obstetrics and Gynecology, The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Susan Kirwin
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Katherine Robbins
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Kathleen M B Vinette
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Alan Daneman
- Department of Diagnostic Imaging, Division of General Radiology and Body Imaging, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Christian R Marshall
- Genome Diagnostics, Department of Paediatric Medicine, The Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, M5S 1A8 Toronto, Ontario, Canada
| | - Carol Collins
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, USA
| | - Kenneth Thummel
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, USA
| | - Etienne Sochett
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Michael A Levine
- Division of Endocrinology and Diabetes and Center for Bone Health, Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Parathyroid Disease in Pregnancy and Lactation: A Narrative Review of the Literature. Biomedicines 2021; 9:biomedicines9050475. [PMID: 33925967 PMCID: PMC8145477 DOI: 10.3390/biomedicines9050475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 12/27/2022] Open
Abstract
Pregnancy and lactation are characterized by sophisticated adaptations of calcium homeostasis, aiming to meet fetal, neonatal, and maternal calcium requirements. Pregnancy is primarily characterized by an enhancement of intestinal calcium absorption, whereas during lactation additional calcium is obtained through resorption from the maternal skeleton, a process which leads to bone loss but is reversible following weaning. These maternal adaptations during pregnancy and lactation may influence or confound the presentation, diagnosis, and management of parathyroid disorders such as primary hyperparathyroidism or hypoparathyroidism. Parathyroid diseases are uncommon in these settings but can be severe when they occur and may affect both maternal and fetal health. This review aims to delineate the changes in calcium physiology that occur with pregnancy and lactation, describe the disorders of calcium and parathyroid physiology that can occur, and outline treatment strategies for these diseases in the above settings.
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Griffin TP, Joyce CM, Alkanderi S, Blake LM, O’Keeffe DT, Bogdanet D, Islam MN, Dennedy MC, Gillan JE, Morrison JJ, O’Brien T, Sayer JA, Bell M, O’Shea PM. Biallelic CYP24A1 variants presenting during pregnancy: clinical and biochemical phenotypes. Endocr Connect 2020; 9:530-541. [PMID: 32375123 PMCID: PMC7354719 DOI: 10.1530/ec-20-0150] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Inactivating mutations in CYP24A1, encoding vitamin D-24-hydroxylase, can lead to an accumulation of active vitamin D metabolites and consequent hypercalcaemia. Patient (infantile and adult) presentation is varied and includes mild-severe hypercalcaemia, hypercalciuria, nephrocalcinosis and nephrolithiasis. This study aimed to characterize the clinical and biochemical phenotypes of a family with two CYP24A1 missense variants. METHODS The proband and seven family members underwent detailed clinical and biochemical evaluation. Laboratory measurements included serum calcium, intact parathyroid hormone (iPTH), vitamin D metabolites and urine calcium and creatinine. RESULTS The proband presented during the second trimester of a planned pregnancy with flu-like symptoms. Laboratory tests showed elevated adjusted calcium of 3.27 (upper reference limit (URL: 2.30) mmol/L), suppressed iPTH (<6 ng/L), elevated 25(OH)D (264 (URL: 55) nmol/L) and elevated 1,25(OH)D (293 (URL: <280) pmol/L). Ionized calcium was 1.55 (URL: 1.28) mmol/L. Sanger sequencing revealed two heterozygous missense variants in the CYP24A1: p.(Arg439Cys), R439C and p.(Trp275Arg), W275R. The proband's brother and sister had the same genotype. The brother had intermittent hypercalcaemia and hypervitaminosis D. Only the sister had a history of nephrolithiasis. The proband's daughter and two nephews were heterozygous for the R439C variant. The proband and her brother frequently had elevated 25(OH)D:24,25(OH)2D ratios (>50) during follow-up. CONCLUSIONS W275R is a new pathogenic CYP24A1 mutation in compound heterozygotic form with R439C in this family.
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Affiliation(s)
- Tomás P Griffin
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
- Regenerative Medicine Institute at CÚRAM SFI Research Centre, School of Medicine, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Caroline M Joyce
- Department of Clinical Biochemistry, Cork University Hospital, Cork, Ireland
| | - Sumaya Alkanderi
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Liam M Blake
- Department of Clinical Biochemistry, SUHCG, GUH, Galway, Ireland
| | - Derek T O’Keeffe
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
| | - Delia Bogdanet
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
| | - Md Nahidul Islam
- Regenerative Medicine Institute at CÚRAM SFI Research Centre, School of Medicine, National University of Ireland Galway (NUIG), Galway, Ireland
- Department of Clinical Biochemistry, SUHCG, GUH, Galway, Ireland
| | - Michael C Dennedy
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
- Lambe Institute for Translational Research, School of Medicine, NUIG, Galway, Ireland
| | - John E Gillan
- Department of Histopathology, SUHCG, GUH, Galway, Ireland
| | - John J Morrison
- Department of Obstetrics and Gynaecology, SUHCG, GUH, Galway, Ireland
| | - Timothy O’Brien
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
- Regenerative Medicine Institute at CÚRAM SFI Research Centre, School of Medicine, National University of Ireland Galway (NUIG), Galway, Ireland
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Newcastle upon Tyne NHS Hospitals Foundation Trust, Newcastle upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne, UK
| | - Marcia Bell
- Centre for Endocrinology, Diabetes and Metabolism, Saolta University Health Care Group (SUHCG), Galway University Hospitals (GUH), Galway, Ireland
| | - Paula M O’Shea
- Department of Clinical Biochemistry, SUHCG, GUH, Galway, Ireland
- Correspondence should be addressed to P M O’Shea:
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Schoenmakers I, Piec I, Baban S, Bärebring L, Green D, Washbourne CJ, Tang JCY, Fraser WD, Augustin H. Gestational hypercalcemia: Prevalence and biochemical profile. J Steroid Biochem Mol Biol 2020; 199:105611. [PMID: 32007562 DOI: 10.1016/j.jsbmb.2020.105611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/08/2020] [Accepted: 01/29/2020] [Indexed: 11/25/2022]
Abstract
Gestational hypercalcemia is associated with an increased risk of maternal, fetal and neonatal morbidity and mortality. Hypercalcemia may develop during pregnancy in individuals who were previously asymptomatic. The increased sensitivity during pregnancy may be related to physiological, gestational alterations in vitamin D and calcium metabolism and may be influenced by gene variants. The prevalence is unknown. We investigated the prevalence of hypercalcemia in trimester 3 (T3) in a population representative prospective cohort study (n = 1832) in South-West Sweden. Women with serum albumin (Alb) adjusted calcium (CaAlb) ≥ 2.65 mmol/L in T3 (n = 30) were matched to normo-calcemic controls, and markers of calcium and vitamin D metabolism were investigated in trimester 1 (T1) and T3. Serum concentrations of Ca, phosphate (P), Magnesium (Mg), Alb and creatinine (Cr), parathyroid hormone (PTH; T3 only), vitamin D metabolites (total 25(OH)D, 1,25(OH)2D, 24,25(OH)2D, and free 25(OH)D) were analysed in T1 and T3. CaAlb (Payne; inter-laboratory difference: UEA = 0.15 + 0.9*UGOT; UEA 2.54 = UGOT 2.65) and estimated glomerular filtration rate (eGFR; modified 4-variable MDRD) and vitamin D metabolites ratios (VMR) were calculated. Normally and non-normally distributed data were presented as mean (SD) or median (95 %CI). Group differences in relationships between vitamin D metabolites and with PTH were investigated with multiple regression analyses. Hypercalcemia in T3 was found in 1.7 % of women. PTH concentrations suggestive of primary hyperparathyroidism was found in 1 woman and none had 25(OH)D or 24,25(OH)2D concentrations in the toxicity range or suggestive of mutations in the CYP24A1 gene. CaAlb was significantly higher in hypercalcemic cases compared to controls in T1 (2.44 (2.30-2.80) vs 2.37 (2.25-2.49) mmol/L) and T3 (2.63 (2.52-2.78) vs 2.46 (2.31-2.58) mmol/L). Serum P was higher among cases than controls in T3 (1.12 (0.16) vs 1.07 (0.18) mmol/L) but not in T1 (1.12 (0.18) and 1.12 (0.16) mmol/L). PTH in T3 was lower in cases (1.6 (1.6-2.8) vs 2.3 (2.1-2.8) pmol/L) but 1,25(OH)2D concentrations were similar. There were no significant group differences in serum 25(OH)D, free 25(OH)D, 24,25(OH)2D, Mg, Alb, Cr and eGFR. Regression analyses did not show significant differences between cases and controls in relationships between vitamin D metabolites and with PTH, except for the free 25(OH)D-PTH relationship and a higher free:total 25(OH)D ratio in cases at T1. In conclusion, most common causes of hypercalcemia were excluded in the majority of women. Hypercalcemic women had a relatively high serum 1,25(OH)2D concentration despite an appropriately suppressed PTH, suggestive of abnormal gestational adaptions.
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Affiliation(s)
- I Schoenmakers
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK.
| | - I Piec
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - S Baban
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - L Bärebring
- Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - D Green
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - C J Washbourne
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - J C Y Tang
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - W D Fraser
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, UK
| | - H Augustin
- Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Sweden
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Arnold N, O’Toole V, Huynh T, Smith HC, Luxford C, Clifton-Bligh R, Eastman CJ. Intractable hypercalcaemia during pregnancy and the postpartum secondary to pathogenic variants in CYP24A1. Endocrinol Diabetes Metab Case Rep 2019; 2019:EDM190114. [PMID: 31751313 PMCID: PMC6893306 DOI: 10.1530/edm-19-0114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 10/29/2019] [Indexed: 01/09/2023] Open
Abstract
SUMMARY Parathyroid-independent hypercalcaemia of pregnancy, due to biallelic loss of function of the P450 enzyme CYP24A1, the principal inactivator of 1,25(OH)2D results in hypervitaminosis D, hypercalcaemia and hypercalciuria. We report two cases of this disorder, with intractable hypercalcaemia, one occurring during gestation and into the postpartum, and the other in the postpartum period. Case 1, a 47-year-old woman with a twin pregnancy conceived by embryo transfer, presented with hypercalcaemia at 23 weeks gestation with subnormal serum parathyroid hormone (PTH) and normal serum 25-OH D levels. She was admitted to hospital at 31 weeks gestation with pregnancy-induced hypertension, gestational diabetes and increasing hypercalcaemia. Caesarean section at 34 weeks gestation delivered two healthy females weighing 2.13 kg and 2.51 kg. At delivery, the patient's serum calcium level was 2.90 mmol/L. Postpartum severe hypercalcaemia was treated successfully with Denosumab 60 mg SCI, given on two occasions. CYP24A1 testing revealed she was compound heterozygous for pathogenic variants c.427_429delGAA, (p.Glu143del) and c.1186C>T, (p.Arg396Trp). Case 2, a 36-year-old woman presented 4 days after the delivery of healthy twins with dyspnoea, bradycardia, severe headaches, hypertension and generalized tonic-clonic seizures after an uneventful pregnancy. She was hypercalcaemic with a suppressed PTH, normal 25(OH)D, and elevated 1,25(OH)2D levels. Her symptoms partially responded to i.v. saline and corticosteroids in the short term but bisphosphonates such as Pamidronate and Zoledronic acid did not result in sustained improvement. Denosumab 120 mg SCI successfully treated the hypercalcaemia which resolved completely 2 months post-partum. CYP24A1 testing revealed she was homozygous for the pathogenic variant c.427_429delGAA, (p.Glu143del). LEARNING POINTS Hypercalcaemia in pregnancy can be associated with considerable morbidity with few options available for management. In non-PTH-related hypercalcaemia the diagnosis of CYP24A1 deficiency should be considered. Making a definitive diagnosis of CYP24A1 deficiency by genetic testing delays the diagnosis, while the availability of serum 24,25-dihydroxyvitamin D (24,25(OH)2D) will expedite a diagnosis. In pregnant women with CYP24A1 deficiency hypercalcaemia can worsen in the post-partum period and is more likely to occur with twin pregnancies but generally resolves within 2-3 months. Therapeutic alternatives are limited in pregnancy and their effectiveness is short-lived and mostly ineffective. Denosumab used in both our patients after delivery was the most effective agent normalizing calcium and may have benefit as a long-term therapeutic agent in preventing complications in patients with CYP24A1 deficiency.
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Affiliation(s)
- Nirusha Arnold
- Westmead Private Hospital, Westmead, Sydney, New South Wales, Australia
| | - Victor O’Toole
- Westmead Private Hospital, Westmead, Sydney, New South Wales, Australia
| | - Tien Huynh
- Westmead Private Hospital, Westmead, Sydney, New South Wales, Australia
| | - Howard C Smith
- Westmead Teaching Hospital, Royal North Shore Teaching Hospital, The University of Sydney, Sydney, New South Wales, Australia
| | - Catherine Luxford
- Kolling Institute of Medical Research, Royal North Shore Teaching Hospital, The University of Sydney, Sydney, New South Wales, Australia
| | - Roderick Clifton-Bligh
- Kolling Institute of Medical Research, Royal North Shore Teaching Hospital, The University of Sydney, Sydney, New South Wales, Australia
| | - Creswell J Eastman
- Westmead Private Hospital, Westmead, Sydney, New South Wales, Australia
- Westmead Teaching Hospital, Royal North Shore Teaching Hospital, The University of Sydney, Sydney, New South Wales, Australia
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