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Aftab S, Khan SA, Malik MI, Imran A, Anjum MN, Saeed A, Qureshi AA, Cheema HA. Clinical spectrum and diagnostic challenges of vitamin D dependent rickets type 1A (VDDR1A) caused by CYP27B1 mutation in resource limited countries. J Pediatr Endocrinol Metab 2023; 36:152-157. [PMID: 36524979 DOI: 10.1515/jpem-2022-0550] [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: 10/27/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022]
Abstract
OBJECTIVES Vitamin D dependent rickets type 1A (VDDR1A) is a rare autosomal recessive condition due to inactivating mutation of CYP27B1. It mimics clinically, biochemically and rediologically to nutritional and hypophosphatemic rickets. In developing countries like Pakistan, VDDR1A is often misdiagnosed as nutritional rickets or hypophosphatemic rickets due lack of free access to 1,25 (OH) 2 D level and genetic testing. This study was aimed to determine the clinical spectrum and diagnostic challenges of VDDR1A due to CYP27B1 mutation in developing countries. METHODS Retrospective review of all cases of VDDR1A due to CYP27B1 mutation over a period of two years presenting in the Pediatric Endocrine clinic of Hameed Latif Hospital, Lahore, Pakistan. RESULTS Six cases of VDDR1A (4 males) were identified. Mean age of clinical manifestation was 14 (9-24) months. Mean age of presentation to endocrine department was 5.5 (1.5-11.8) years. Growth failure and bony deformities were the most common presentation (n=6), followed by repeated diarrheas and abdominal distension (n=3) and recurrent fractures (n=1). All cases shared same biochemical profile of low/normal calcium, hypophosphatemia, raised alkaline phosphatase, raised PTH, normal/high 25(OH)D and tubular reabsorption of phosphate (TRP) <85%. Patients treated with calcitriol showed rapid healing as compared to those treated with 1-alfacalcidol. CONCLUSIONS We should have a high index of suspicion of VDDR1A in rickets not responding to cholecalciferol therapy.
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Affiliation(s)
- Sommayya Aftab
- Department of Paediatric Endocrinology and Diabetes, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan.,Paediatric Endocrinology, Hameed Lateef Hospital, Lahore, Pakistan
| | - Sabeen Abid Khan
- Department of Paediatrics, Shifa College of Medicine, Shifa Tameer-r-Millat University, Islamabad
| | - Munir Iqbal Malik
- Department of Paediatrics, Shifa College of Medicine, Shifa Tameer-e-Millat University, Islamabad, Pakistan.,Consultant Paediatric Gastroenterologist, Shifa International Hospital, Islamabad, Pakistan
| | - Ahmed Imran
- Department of Paediatric Radiology, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan
| | - Muhammad Nadeem Anjum
- Department of Paediatric Gastroenterology , Hepatology and Nutrition, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan
| | - Anjum Saeed
- Department of Paediatric Gastroenterology , Hepatology and Nutrition, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan
| | - Abid Ali Qureshi
- Department of Paediatric Radiology, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan
| | - Huma Arshad Cheema
- Department of Paediatric Gastroenterology , Hepatology and Nutrition, University of Child Health Sciences, The Children's Hospital, Lahore, Pakistan
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Kaygusuz SB, Alavanda C, Kirkgoz T, Eltan M, Yavas Abali Z, Helvacioglu D, Guran T, Ata P, Bereket A, Turan S. Does Genotype-Phenotype Correlation Exist in Vitamin D-Dependent Rickets Type IA: Report of 13 New Cases and Review of the Literature. Calcif Tissue Int 2021; 108:576-586. [PMID: 33386952 DOI: 10.1007/s00223-020-00784-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/28/2020] [Indexed: 11/28/2022]
Abstract
Vitamin D-dependent rickets type IA (VDDR-IA) is caused by biallelic mutations in CYP27B1. Data regarding genotype-phenotype correlation in VDDR-IA are scarce. Here, we aimed to investigate clinical/genotypic features and long-term follow-up of 13 new cases with VDDR-IA and genotype-phenotype correlation of reported cases in the literature. Thirteen patients with VDDR-IA were evaluated. Eight patients had reached their final height at the time of the study and, for whom, long-term outcome data were analyzed. Further, all VDDR-IA patients in the literature (n:183) were analyzed and clinical-genetic features were recorded. The median age of diagnosis was 2.55 ± 1.13 (1.0-12) years. Initial diagnoses before referral to our clinic were nutritional rickets (n:7), hypophosphatemic rickets (n:2), and pseudohypoparathyroidism (n:1). All had biochemical evidence suggestive of VDDR-IA; except one with elevated 1,25(OH)2D3 and another with hyperphosphatemia, in whom pseudohypoparathyroidism was excluded with molecular tests. Combined analyses of our cohort and other series in the literature demonstrated that three most common CYP27B1 mutations are p.F443Pfs*24, c.195 + 2T > G, and p.V88Wfs*71. In Turkish population, p.K192E mutation along with the former two is the most common mutations. Comparison of clinical features demonstrated that c.195 + 2T > G mutation causes the most severe and p.K192E mutation causes the least severe phenotype with respect to age and height at presentation and calcitriol requirement. We found a clear genotype-phenotype correlation in VDDR-IA, notably CYP27B1 intronic c.195 + 2T > G mutation causes a more severe phenotype with lower height SDS at presentation and, higher calcitriol requirement, while less severe phenotype occurs in p.K192E mutation.
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Affiliation(s)
- Sare Betul Kaygusuz
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Ceren Alavanda
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Tarik Kirkgoz
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Mehmet Eltan
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Zehra Yavas Abali
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Didem Helvacioglu
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Tulay Guran
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Pinar Ata
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Abdullah Bereket
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey
| | - Serap Turan
- Department of Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey.
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Zou M, Guven A, BinEssa HA, Al-Rijjal RA, Meyer BF, Alzahrani AS, Shi Y. Molecular Analysis of CYP27B1 Mutations in Vitamin D-Dependent Rickets Type 1A: c.590G > A (p.G197D) Missense Mutation Causes a RNA Splicing Error. Front Genet 2020; 11:607517. [PMID: 33329754 PMCID: PMC7729158 DOI: 10.3389/fgene.2020.607517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/10/2020] [Indexed: 11/22/2022] Open
Abstract
Context Vitamin D-dependent rickets type 1A (VDDR1A) is a rare autosomal recessively inherited disorder due to loss-of-function mutations in the CYP27B1 gene. CYP27B1 encodes an enzyme of 25-hydroxyvitamin D-1α-hydroxylase for converting inactive 25-OHD to biologically active 1,25-(OH)2D. Objective To identify underlying genetic defects in patients with VDDR1A. Methods Twelve patients from 7 Turkish and 2 Saudi families were investigated. The coding exons and intron-exon boundaries of the CYP27B1 gene were amplified by Polymerase Chain Reaction (PCR) from peripheral lymphocyte DNA. PCR products were directly sequenced. The consequences of c.590G > A mutation were analyzed by in silico and functional analysis. Results CYP27B1 mutations were identified in all the patients. Two novel mutations were identified in two separate families: c.171delG (family 7) and c.398_400dupAAT (family 8). The intra-exon deletion of c.171delG resulted in a frameshift and premature stop codon 20 amino acids downstream from the mutation (p.L58Cfs∗20). The intra-exon duplication of c.398_400dupAAT generated a premature stop codon at the mutation site (p.W134∗). A missense c.590G > A (p.G197D) mutation was found in a patient from family 4 and caused a defect in pre-mRNA splicing. As a result, two populations of transcripts were detected: the majority of them with intron 3 retention (83%), and the minority (17%) being properly spliced transcripts with about 16% of wild-type enzymatic activity. The remaining nine patients from six families carried a previously reported c.1319_1325dupCCCACCC (F443Pfs∗24) mutation. Clinically, all the patients need continued calcitriol treatment, which was consistent with inactivation of 25-hydroxy vitamin D1α-hydroxylase activity. Conclusion Two novel frameshift CYP27B1 mutations were identified and predicted to inactivate 25-hydroxyvitamin D-1α-hydroxylase. The loss of enzymatic activity by c.590G > A missense mutation was mainly caused by aberrant pre-mRNA splicing.
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Affiliation(s)
- Minjing Zou
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ayla Guven
- Pediatric Endocrinology Clinic, Zeynep Kamil Women and Children Hospital, University of Health Science, Istanbul, Turkey
| | - Huda A BinEssa
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Roua A Al-Rijjal
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Brian F Meyer
- Pediatric Endocrinology Clinic, Zeynep Kamil Women and Children Hospital, University of Health Science, Istanbul, Turkey
| | - Ali S Alzahrani
- Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Yufei Shi
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Li Y, Yuan X, Chen R, Lin X, Shangguan H, Yang X, Zhang Y. Clinical and genetic analysis of two Chinese families with vitamin D-dependent rickets type IA and follow-up. Orphanet J Rare Dis 2020; 15:273. [PMID: 33004071 PMCID: PMC7528464 DOI: 10.1186/s13023-020-01558-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 09/23/2020] [Indexed: 12/02/2022] Open
Abstract
Objective Vitamin D-dependent rickets type IA (VDDR-IA) is a rare autosomal recessive disorder characterized by the early onset of severe rickets. The objectives of this study were twofold: (1) to analyze the clinical characteristics and therapy of two patients with VDDR-IA from two separate Chinese families, and (2) investigate the CYP27B1 gene mutations in two large pedigrees. Methods Medical history, clinical manifestations, physical examination, radiological findings and laboratory data were analyzed from two patients with VDDR-IA. Serum 1, 25-dihydroxyvitamin D [1, 25-(OH)2D3] of the two patients and their respective families were measured by ELISA and blood samples from both families was obtained for CYP27B1 gene sequence. Results Two patients had typical manifestations and radiological evidence of rickets. Laboratory data showed hypocalcaemia and hypophosphataemia, along with high levels of serum alkaline phosphatase, parathyroid hormone and 25-hydroxyvitamin D3. However, serum 1,25-(OH)2D3 level were low in the patients but normal in their family members. Genetic sequence identified two patients were homozygous for a duplication mutation in exon 8 of CYP27B1 gene (c.1319_1325dupCCCACCC, p.Phe443Profs * 24). After treating with calcitriol and calcium, there was biochemical improvement with normalization of serum calcium and phosphorus, and radiographic evidence of compensatory skeletal mineralization. One patient developed nephrocalcinosis during follow-up. Conclusions This study identified a recurrent seven-nucleotide insertion of CYP27B1 in two large pedigrees, and compared the clinical characteristics and individual therapy of two affected patients. Additionally, our experience further supports the notion that nephrocalcinosis can occur even on standard doses of calcitriol and oral calcium, and normal level of serum calcium, phosphorus, PTH and 25-(OH)D3.
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Affiliation(s)
- Yunfei Li
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China.,Affiliated Dongfeng General Hospital of Hubei Medical College, Shiyan, 442008, China
| | - Xin Yuan
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China
| | - Ruimin Chen
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China.
| | - Xiangquan Lin
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China
| | - Huakun Shangguan
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China
| | - Xiaohong Yang
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China
| | - Ying Zhang
- Department of Endocrinology, Genetics and Metabolism, Fuzhou Children's Hospital of Fujian Medical University, No. 145, 817 Middle Road, Fuzhou, 350005, China
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Dhull RS, Jain R, Deepthi B, Cheong HI, Saha A, Mehndiratta M, Basu S. Vitamin D-dependent rickets (VDDR) type 1: case series of two siblings with a CYP27B1 mutation and review of the literature. ACTA ACUST UNITED AC 2020; 42:494-497. [PMID: 32926064 PMCID: PMC7860650 DOI: 10.1590/2175-8239-jbn-2020-0001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 06/24/2020] [Indexed: 12/02/2022]
Abstract
Two siblings presented with clinical and biochemical features of rickets, initially suspected as hypophosphatemic rickets. There was no improvement initially, hence the siblings were reinvestigated and later diagnosed as having vitamin D-dependent rickets (VDDR) type 1 due to a rare mutation in the CYP27B1 gene encoding the 1α-hydroxylase enzyme. Both siblings improved with calcitriol supplementation. The initial presentation of VDDR is often confusing and algorithmic evaluation helps in diagnosis. We also present a brief review of the literature, including genetics.
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Affiliation(s)
- Rachita Singh Dhull
- Lady Hardinge Medical College and associated Kalawati Saran Children Hospital, Department of Pediatrics, Division of Pediatric Nephrology, New Delhi, India
| | - Reena Jain
- Lady Hardinge Medical College and associated Kalawati Saran Children Hospital, Department of Pediatrics, Division of Pediatric Nephrology, New Delhi, India
| | - Bobbity Deepthi
- Lady Hardinge Medical College and associated Kalawati Saran Children Hospital, Department of Pediatrics, Division of Pediatric Nephrology, New Delhi, India
| | - Hae Ii Cheong
- Seoul National University Children's Hospital, Department of Pediatrics, Seoul, Korea.,Seoul National University College of Medicine, Kidney Research Institute, Medical Research Centre, Seoul, Korea
| | - Abhijeet Saha
- Lady Hardinge Medical College and associated Kalawati Saran Children Hospital, Department of Pediatrics, Division of Pediatric Nephrology, New Delhi, India
| | - Mohit Mehndiratta
- University College of Medical Sciences, Department of Biochemistry, New Delhi, India
| | - Srikanta Basu
- Lady Hardinge Medical College and associated Kalawati Saran Children Hospital, Department of Pediatrics, Division of Pediatric Nephrology, New Delhi, India
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Kim YM, Jang YY, Jeong JE, Park HJ, Jang JH, Kim JK. A case of vitamin D hydroxylation-deficient rickets type 1A caused by 2 novel pathogenic variants in CYP27B1 gene. Ann Pediatr Endocrinol Metab 2019; 24:137-141. [PMID: 31261480 PMCID: PMC6603605 DOI: 10.6065/apem.2019.24.2.137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 03/11/2019] [Indexed: 11/20/2022] Open
Abstract
Vitamin D hydroxylation-deficient rickets type 1A (VDDR1A, OMIM 264700) is a rare autosomal recessive inherited disorder. Pathogenic variants in the CYP27B1 gene lead to loss of 1α-hydroxylase activity. We report the case of a 22-month-old toddler who presented with growth retardation and delayed development. The patient exhibited the typical laboratory findings of VDDR1A, including hypocalcemia (calcium: 5.2 mg/dL), elevated serum level of alkaline phosphatase (2,600 U/L), elevated serum level of intact-parathyroid hormone (238 pg/mL), low 1,25(OH)2D3 level (11.2 pg/mL), and normal 25(OH)D3 level (40.7 ng/mL). His height and weight were 76.5 cm and 9.5 kg, respectively (both <3rd percentile). The Bayley Scales of Infant and Toddler Development II indicated significantly delayed development (mental development index <50, psychomotor development index <50). The patient was a compound heterozygous for two novel pathogenic variants in the CYP27B1 gene: c.57_69del (p.Glu20Profs*2) and c.171dupG (p.Leu58Alafs*275), inherited from his mother and father, respectively. The patient showed remarkable improvement after treatment with calcitriol and calcium carbonate.
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Affiliation(s)
- You-Min Kim
- Department of Pediatrics, Catholic University of Daegu School of Medicine, Daegu, Korea
| | - Yoon-Young Jang
- Department of Pediatrics, Catholic University of Daegu School of Medicine, Daegu, Korea
| | - Ji-Eun Jeong
- Department of Pediatrics, Catholic University of Daegu School of Medicine, Daegu, Korea
| | - Hye-Jin Park
- Department of Pediatrics, Catholic University of Daegu School of Medicine, Daegu, Korea
| | | | - Jin-Kyung Kim
- Department of Pediatrics, Catholic University of Daegu School of Medicine, Daegu, Korea,Address for correspondence: Jin-Kyung Kim, MD, PhD Department of Pediatrics, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17- gil, Nam-gu, Daegu 42472, Korea Tel: +82-53-650-4240 Fax: +82-53-621-4106 E-mail:
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Chi Y, Sun J, Pang L, Jiajue R, Jiang Y, Wang O, Li M, Xing X, Hu Y, Zhou X, Meng X, Xia W. Mutation update and long-term outcome after treatment with active vitamin D 3 in Chinese patients with pseudovitamin D-deficiency rickets (PDDR). Osteoporos Int 2019; 30:481-489. [PMID: 30382318 DOI: 10.1007/s00198-018-4607-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 06/15/2018] [Indexed: 01/08/2023]
Abstract
UNLABELLED Pseudovitamin D-deficiency rickets is a rare disease which is caused by CYP27B1. In this study, we identified 9 mutations in 7 PDDR patients. In addition, we observed the response to long-term treatment of calcitriol in 15 Chinese patients with PDDR, which showed that the biochemical abnormalities had been corrected satisfactorily after 1-year treatment. INTRODUCTION Pseudovitamin D-deficiency rickets is a rare autosomal recessive disorder resulting from a defect in 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by CYP27B1. The purpose of this study was to identify the CYP27B1 mutations and investigate the response to long-term treatment of calcitriol in Chinese patients with PDDR. METHODS We investigated CYP27B1 mutations in seven individuals from six separate families. To investigate the response to long-term (13 years) treatment with calcitriol in PDDR patients, we additionally collected clinical data of eight families from our previous report and analyzed their biochemical parameter and radiographic changes during the treatment. RESULTS Nine different mutations were identified: two novel missense mutations (G194R, R259L), three novel and one reported deletion mutations (c1442delA, c1504delA, c311-321del, and c. 48-60del), two novel nonsense mutations (c.85G>T, c.580G>T), and a reported insertion mutation (c1325-1332insCCCACCC). The statistical analysis revealed that parathyroid hormone (PTH) and ALP significantly decreased after 6-month and 1-year treatment with calcitriol respectively. Urine calcium was measured in all the patients without kidney stones being documented. After 6-year treatment, the radiographic abnormalities had also been improved. Two patients who had reached their final height are both with short stature (height Z-score below - 2.0). CONCLUSIONS We identified seven novel mutations of CYP27B1 gene in seven Chinese PDDR families. Our findings revealed after 1-year treatment of active vitamin D3, PTH and ALP significantly decreased. The correction of the biochemical abnormalities had not improved the final height satisfactorily.
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Affiliation(s)
- Y Chi
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - J Sun
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - L Pang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - R Jiajue
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - Y Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - O Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - M Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - X Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - Y Hu
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - X Zhou
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - X Meng
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China
| | - W Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing, 100730, China.
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Abstract
Rickets is a metabolic bone disease that develops as a result of inadequate mineralization of growing bone due to disruption of calcium, phosphorus and/or vitamin D metabolism. Nutritional rickets remains a significant child health problem in developing countries. In addition, several rare genetic causes of rickets have also been described, which can be divided into two groups. The first group consists of genetic disorders of vitamin D biosynthesis and action, such as vitamin D-dependent rickets type 1A (VDDR1A), vitamin D-dependent rickets type 1B (VDDR1B), vitamin D-dependent rickets type 2A (VDDR2A), and vitamin D-dependent rickets type 2B (VDDR2B). The second group involves genetic disorders of excessive renal phosphate loss (hereditary hypophosphatemic rickets) due to impairment in renal tubular phosphate reabsorption as a result of FGF23-related or FGF23-independent causes. In this review, we focus on clinical, laboratory and genetic characteristics of various types of hereditary rickets as well as differential diagnosis and treatment approaches.
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Affiliation(s)
- Sezer Acar
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey
| | - Korcan Demir
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey
| | - Yufei Shi
- King Faisal Specialist Hospital & Research Centre, Department of Genetics, Riyadh, Saudi Arabia
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Craniofacial and dental characteristics of patients with vitamin-D-dependent rickets type 1A compared to controls and patients with X-linked hypophosphatemia. Clin Oral Investig 2017; 22:745-755. [PMID: 28608052 DOI: 10.1007/s00784-017-2149-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
Abstract
ᅟOBJECTIVES: Vitamin-D-dependent rickets type 1A (VDDR1A) is a rare inherited disease caused by defective activation of vitamin D. The aim of the study was to describe the craniofacial characteristics and the dental phenotype of patients with genetically confirmed VDDR1A. The VDDR1A findings were compared to findings in patients with X-linked hypophosphatemia (XLH) and healthy controls. MATERIAL AND METHODS Ten patients with VDDR1A were identified. The reference group for the comparison of cephalometric findings was 49 adults without chronic disease. The reference group for the comparison of dental findings was 30 adults with XLH. Clinical examination, clinical photos, and radiographs were obtained. Cephalometric analysis was performed. Photos and radiographs were visually evaluated. RESULTS The depth of the posterior cranial fossa (d-p and d-s-iop) in VDDR1A adults was reduced compared to the reference group (p < 0.05). Five (83%) of six adults with VDDR1A and one (4%) of 25 adults with XLH had enamel hypoplasia on several incisors and/or canines (p < 0.001). Three (75%) of four adults with VDDR1A and none of 16 adults with XLH had several first molars with enamel hypoplasia (p = 0.004). Five of 7 (71%) adults with VDDR1A and 24 of 30 (80%) adults with XLH had endodontically affected teeth. CONCLUSIONS The dental aberration of VDDR1A is more in line with the dental aberration of nutritional rickets than with the dental aberrations in XLH, suggesting the combination of low availability of both calcium and phosphate to be critical in periods of enamel formation. CLINICAL RELEVANCE Knowledge on craniofacial and dental aberration in patients with rare diseases, e.g., inherited rickets, is of importance to the dental practitioner, especially during diagnostics and treatment in special care units.
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Özcabı B, Tahmiscioğlu Bucak F, Jaferova S, Oruç Ç, Adrovic A, Ceylaner S, Ercan O, Evliyaoğlu O. A Case of Vitamin D-Dependent Rickets Type 1A with a Novel Mutation in the Uzbek Population. J Clin Res Pediatr Endocrinol 2016; 8:484-489. [PMID: 27353739 PMCID: PMC5198011 DOI: 10.4274/jcrpe.3128] [Citation(s) in RCA: 4] [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] [Indexed: 12/01/2022] Open
Abstract
Vitamin D-dependent rickets type 1A (VDDR-1A) (Online Mendelian Inheritance in Man #264700) is a rare, autosomal recessively inherited disorder due to inactivating mutations in CYP27B1. It is characterized by early onset of rickets with hypocalcemia. We aimed to describe the clinical and laboratory findings in a VDDR-1A case and to report a novel homozygote truncating mutation NM_000785.3 c.403C>T (p.Q135*) in CYP27B1 which to our knowledge is the first described mutation in the Uzbek population. The patient was admitted with tetany at the age of 12 months. He was a healthy Uzbek boy until 9 months of age when he had a seizure due to hypocalcemia. Vitamin D treatment was given orally in Turkmenistan (no data available for dose and duration). The patient was the product of a consanguineous marriage. His brother had died with hypocalcemia and pneumonia. At physical examination, anthropometric measurements were within normal limits; he had caput quadratum, enlarged wrists, and carpopedal spasm. Blood calcium, phosphorus, alkaline phosphatase, and parathormone (PTH) levels were 5.9 mg/dL, 3.5 mg/dL, 987 IU/L, and 182.8 pg/mL (12-72), respectively. Radiological findings included cupping and fraying of the radial and ulnar metaphyses. Renal ultrasound revealed nephrocalcinosis (grade 1). Despite high serum PTH and 25-hydroxyvitamin D3 levels, 1,25-dihydroxyvitamin D3 level was low, suggesting a diagnosis of VDDR-1A. The patient was treated with calcium carbonate and calcitriol. DNA sequencing revealed a novel homozygous mutation of NM_000785.3 c.403C>T (p.Q135*) in CYP27B1. VDDR-1A is a rare disorder which needs to be considered even in countries where nutritional vitamin D deficiency is still common.
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Affiliation(s)
- Bahar Özcabı
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Feride Tahmiscioğlu Bucak
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Sevinç Jaferova
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Çiğdem Oruç
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Amra Adrovic
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Serdar Ceylaner
- Intergen Genetic Center and Yüksek İhtisas University Faculty of Medicine, Department of Medical Genetics, Ankara, Turkey
| | - Oya Ercan
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Olcay Evliyaoğlu
- İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey, E-mail:
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Abstract
Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.
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Affiliation(s)
- Peter J Tebben
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ravinder J Singh
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Rajiv Kumar
- Divisions of Endocrinology (P.J.T., R.K.) and Nephrology and Hypertension (R.K.), and Departments of Pediatric and Adolescent Medicine (P.J.T.), Internal Medicine (P.J.T., R.K.), Laboratory Medicine and Pathology (R.J.S.), and Biochemistry in Molecular Biology (R.K.), Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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Füchtbauer L, Brusgaard K, Ledaal P, Frost M, Frederiksen AL. Case report: vitamin D-dependent rickets type 1 caused by a novel CYP27B1 mutation. Clin Case Rep 2015; 3:1012-6. [PMID: 26734137 PMCID: PMC4693699 DOI: 10.1002/ccr3.406] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/17/2015] [Accepted: 08/27/2015] [Indexed: 01/31/2023] Open
Abstract
Vitamin D‐dependent rickets type 1 VDDR‐1 is a recessive inherited disorder with impaired activation of vitamin D, caused by mutations in CYP27B1. We present long‐time follow‐up of a case with a novel mutation including high‐resolution peripheral quantitative computed tomography of the bone. Adequate treatment resulted in a normalized phenotype.
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Affiliation(s)
- Laila Füchtbauer
- Department of Endocrinology Sahlgrenska Universitetssjukhuset Gothenburg Sweden
| | - Klaus Brusgaard
- Department of Clinical Genetics Odense University Hospital Odense Denmark
| | - Pål Ledaal
- Pediatric Department Sygehus Sønderjylland Sønderborg Denmark
| | - Morten Frost
- Department of Endocrinology M Odense University Hospital Odense Denmark
| | - Anja L Frederiksen
- Department of Clinical Genetics Odense University Hospital Odense Denmark
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Thacher TD, Fischer PR, Singh RJ, Roizen J, Levine MA. CYP2R1 Mutations Impair Generation of 25-hydroxyvitamin D and Cause an Atypical Form of Vitamin D Deficiency. J Clin Endocrinol Metab 2015; 100:E1005-13. [PMID: 25942481 PMCID: PMC4490307 DOI: 10.1210/jc.2015-1746] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/01/2015] [Indexed: 12/14/2022]
Abstract
CONTEXT Production of the active vitamin D hormone 1,25-dihydroxyvitamin D requires hepatic 25-hydroxylation of vitamin D. The CYP2R1 gene encodes the principal vitamin D 25-hydroxylase in humans. OBJECTIVE This study aimed to determine the prevalence of CYP2R1 mutations in Nigerian children with familial rickets and vitamin D deficiency and assess the functional effect on 25-hydroxylase activity. DESIGN AND PARTICIPANTS We sequenced the CYP2R1 gene in subjects with sporadic rickets and affected subjects from families in which more than one member had rickets. MAIN OUTCOME MEASURES Function of mutant CYP2R1 genes as assessed in vivo by serum 25-hydroxyvitamin D values after administration of vitamin D and in vitro by analysis of mutant forms of the CYP2R1. RESULTS CYP2R1 sequences were normal in 27 children with sporadic rickets, but missense mutations were identified in affected members of 2 of 12 families, a previously identified L99P, and a novel K242N. In silico analyses predicted that both substitutions would have deleterious effects on the variant proteins, and in vitro studies showed that K242N and L99P had markedly reduced or complete loss of 25-hydroxylase activity, respectively. Heterozygous subjects were less affected than homozygous subjects, and oral administration of vitamin D led to significantly lower increases in serum 25-hydroxyvitamin D in heterozygous than in control subjects, whereas homozygous subjects showed negligible increases. CONCLUSION These studies confirm that CYP2R1 is the principal 25-hydroxylase in humans and demonstrate that CYP2R1 alleles have dosage-dependent effects on vitamin D homeostasis. CYP2R1 mutations cause a novel form of genetic vitamin D deficiency with semidominant inheritance.
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Affiliation(s)
- Tom D Thacher
- Department of Family Medicine (T.D.T.), Jos University Teaching Hospital, Jos, Nigeria 930241; Department of Family Medicine (T.D.T.), Department of Pediatric and Adolescent Medicine (P.R.F.), and Department of Laboratory Medicine and Pathology (R.J.S.), Mayo Clinic, Rochester, Minnesota 55905; and The Children's Hospital of Philadelphia and Department of Pediatrics (J.R., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Philip R Fischer
- Department of Family Medicine (T.D.T.), Jos University Teaching Hospital, Jos, Nigeria 930241; Department of Family Medicine (T.D.T.), Department of Pediatric and Adolescent Medicine (P.R.F.), and Department of Laboratory Medicine and Pathology (R.J.S.), Mayo Clinic, Rochester, Minnesota 55905; and The Children's Hospital of Philadelphia and Department of Pediatrics (J.R., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Ravinder J Singh
- Department of Family Medicine (T.D.T.), Jos University Teaching Hospital, Jos, Nigeria 930241; Department of Family Medicine (T.D.T.), Department of Pediatric and Adolescent Medicine (P.R.F.), and Department of Laboratory Medicine and Pathology (R.J.S.), Mayo Clinic, Rochester, Minnesota 55905; and The Children's Hospital of Philadelphia and Department of Pediatrics (J.R., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Jeffrey Roizen
- Department of Family Medicine (T.D.T.), Jos University Teaching Hospital, Jos, Nigeria 930241; Department of Family Medicine (T.D.T.), Department of Pediatric and Adolescent Medicine (P.R.F.), and Department of Laboratory Medicine and Pathology (R.J.S.), Mayo Clinic, Rochester, Minnesota 55905; and The Children's Hospital of Philadelphia and Department of Pediatrics (J.R., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Michael A Levine
- Department of Family Medicine (T.D.T.), Jos University Teaching Hospital, Jos, Nigeria 930241; Department of Family Medicine (T.D.T.), Department of Pediatric and Adolescent Medicine (P.R.F.), and Department of Laboratory Medicine and Pathology (R.J.S.), Mayo Clinic, Rochester, Minnesota 55905; and The Children's Hospital of Philadelphia and Department of Pediatrics (J.R., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
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Demir K, Kattan WE, Zou M, Durmaz E, BinEssa H, Nalbantoğlu Ö, Al-Rijjal RA, Meyer B, Özkan B, Shi Y. Novel CYP27B1 Gene Mutations in Patients with Vitamin D-Dependent Rickets Type 1A. PLoS One 2015; 10:e0131376. [PMID: 26132292 PMCID: PMC4489500 DOI: 10.1371/journal.pone.0131376] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/31/2015] [Indexed: 12/30/2022] Open
Abstract
The CYP27B1 gene encodes 25-hydroxyvitamin D-1α-hydroxylase. Mutations of this gene cause vitamin D-dependent rickets type 1A (VDDR-IA, OMIM 264700), which is a rare autosomal recessive disorder. To investigate CYP27B1 mutations, we studied 8 patients from 7 unrelated families. All coding exons and intron-exon boundaries of CYP27B1 gene were amplified by PCR from peripheral leukocyte DNA and subsequently sequenced. Homozygous mutations in the CYP27B1 gene were found in all the patients and heterozygous mutations were present in their normal parents. One novel single nucleotide variation (SNV, c.1215 T>C, p.R379R in the last nucleotide of exon 7) and three novel mutations were identified:, a splice donor site mutation (c.1215+2T>A) in intron 7, a 16-bp deletion in exon 6 (c.1022-1037del16), and a 2-bp deletion in exon 5 (c.934_935delAC). Both c.1215 T>C and c.1215+2T>A were present together in homozygous form in two unrelated patients, and caused exon 7 skipping. However, c.1215 T>C alone has no effect on pre-mRNA splicing. The skipping of exon 7 resulted in a shift of downstream reading frame and a premature stop codon 57 amino acids from L380 (p.L380Afs*57). The intra-exon deletions of c.1022-1037del16 and c.934_935delAC also resulted in a frameshift and the creation of premature stop codons at p.T341Rfs*5, and p.T312Rfs*19, respectively, leading to the functional inactivation of the CYP27B1 gene. Clinically, all the patients required continued calcitriol treatment and the clinical presentations were consistent with the complete loss of vitamin D1α-hydroxylase activity. In conclusion, three novel mutations have been identified. All of them caused frameshift and truncated proteins. The silent c.1215 T>C SNV has no effect on pre-mRNA splicing and it is likely a novel SNP. The current study further expands the CYP27B1 mutation spectrum.
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Affiliation(s)
- Korcan Demir
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Hospital, İzmir, Turkey
| | - Walaa E Kattan
- College of Science and General Studies, Alfaisal University, Riyadh, Saudi Arabia; Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Minjing Zou
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Erdem Durmaz
- Department of Pediatric Endocrinology, Sifa University, Bornova Health Application and Research Center, İzmir, Turkey
| | - Huda BinEssa
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Özlem Nalbantoğlu
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Hospital, İzmir, Turkey
| | - Roua A Al-Rijjal
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Brian Meyer
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Behzat Özkan
- Division of Pediatric Endocrinology, Dr. Behçet Uz Children's Hospital, İzmir, Turkey
| | - Yufei Shi
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
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Chanakul A, Zhang MYH, Louw A, Armbrecht HJ, Miller WL, Portale AA, Perwad F. FGF-23 regulates CYP27B1 transcription in the kidney and in extra-renal tissues. PLoS One 2013; 8:e72816. [PMID: 24019880 PMCID: PMC3760837 DOI: 10.1371/journal.pone.0072816] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 07/21/2013] [Indexed: 12/18/2022] Open
Abstract
The mitochondrial enzyme 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by the CYP27B1 gene, converts 25OHD to the biological active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D). Renal 1α-hydroxylase activity is the principal determinant of the circulating 1,25(OH)2D concentration and enzyme activity is tightly regulated by several factors. Fibroblast growth factor-23 (FGF-23) decreases serum 1,25(OH)2D concentrations by suppressing CYP27B1 mRNA abundance in mice. In extra-renal tissues, 1α-hydroxylase is responsible for local 1,25(OH)2D synthesis, which has important paracrine actions, but whether FGF-23 regulates CYP27B1 gene expression in extra-renal tissues is unknown. We sought to determine whether FGF-23 regulates CYP27B1 transcription in the kidney and whether extra-renal tissues are target sites for FGF-23-induced suppression of CYP27B1. In HEK293 cells transfected with the human CYP27B1 promoter, FGF-23 suppressed promoter activity by 70%, and the suppressive effect was blocked by CI-1040, a specific inhibitor of extracellular signal regulated kinase 1/2. To examine CYP27B1 transcriptional activity in vivo, we crossed fgf-23 null mice with mice bearing the CYP27B1 promoter-driven luciferase transgene (1α-Luc). In the kidney of FGF-23 null/1α-Luc mice, CYP27B1 promoter activity was increased by 3-fold compared to that in wild-type/1α-Luc mice. Intraperitoneal injection of FGF-23 suppressed renal CYP27B1 promoter activity and protein expression by 26% and 60% respectively, and the suppressive effect was blocked by PD0325901, an ERK1/2 inhibitor. These findings provide evidence that FGF-23 suppresses CYP27B1 transcription in the kidney. Furthermore, we demonstrate that in FGF-23 null/1α-Luc mice, CYP27B1 promoter activity and mRNA abundance are increased in several extra-renal sites. In the heart of FGF-23 null/1α-Luc mice, CYP27B1 promoter activity and mRNA were 2- and 5-fold higher, respectively, than in control mice. We also observed a 3- to 10-fold increase in CYP27B1 mRNA abundance in the lung, spleen, aorta and testis of FGF-23 null/1α-Luc mice. Thus, we have identified novel extra-renal target sites for FGF-23-mediated regulation of CYP27B1.
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Affiliation(s)
- Ankanee Chanakul
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
| | - Martin Y. H. Zhang
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
| | - Andrew Louw
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
| | - Harvey J. Armbrecht
- Geriatric Research, Education, and Clinical Center, St. Louis Veterans Affairs Medical Center, St. Louis, Missouri, United States of America
| | - Walter L. Miller
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
| | - Anthony A. Portale
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
| | - Farzana Perwad
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Abstract
The molecular identification and characterization of genetic defects leading to a number of rare inherited or acquired disorders affecting phosphate homeostasis has added tremendous detail to our understanding of the regulation of phosphate balance. The identification of the key phosphate-regulating hormone, fibroblast growth factor 23 (FGF23), as well as other molecules that control its production, such as the N-acetylgalactosaminyltransferase 3 GALNT3, the endopeptidase phosphate-regulating protein with homologies to endopeptidases on the X chromosome, and the matrix protein dentin matrix protein 1, and molecules that function as downstream effectors of FGF23, such as the longevity factor Klotho and the phosphate transporters NPT2a and NPT2c, has permitted us to understand the elegant and complex interplay that exists between the kidneys, bone, parathyroid, and gut. Such insights from genetic disorders have allowed not only the design of potent targeted therapies for some of these rare genetic disorders, such as using anti-FGF23 antibodies for treatment of X-linked hypophosphatemic rickets, but also have led to clinically relevant observations related to the dysregulation of mineral ion homeostasis in chronic kidney disease. Thus, we are able to leverage our knowledge of rare human disorders affecting only a few individuals, to understand and potentially treat disease processes that affect millions of patients.
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Abstract
The cytochrome P450 superfamily consists of a large number of heme-containing monooxygenases. Many human P450s metabolize drugs used to treat human diseases. Others are necessary for synthesis of endogenous compounds essential for human physiology. In some instances, alterations in specific P450s affect the biological processes that they mediate and lead to a disease. In this minireview, we describe medically significant human P450s (from families 2, 4, 7, 11, 17, 19, 21, 24, 27, 46, and 51) and the diseases associated with these P450s.
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Affiliation(s)
- Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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18
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Abstract
The vitamin D signal transduction system involves a series of cytochrome P450-containing sterol hydroxylases to generate and degrade the active hormone, 1α,25-dihydroxyvitamin D3, which serves as a ligand for the vitamin D receptor-mediated transcriptional gene expression described in companion articles in this review series. This review updates our current knowledge of the specific anabolic cytochrome P450s involved in 25- and 1α-hydroxylation, as well as the catabolic cytochrome P450 involved in 24- and 23-hydroxylation steps, which are believed to initiate inactivation of the vitamin D molecule. We focus on the biochemical properties of these enzymes; key residues in their active sites derived from crystal structures and mutagenesis studies; the physiological roles of these enzymes as determined by animal knockout studies and human genetic diseases; and the regulation of these different cytochrome P450s by extracellular ions and peptide modulators. We highlight the importance of these cytochrome P450s in the pathogenesis of kidney disease, metabolic bone disease, and hyperproliferative diseases, such as psoriasis and cancer; as well as explore potential future developments in the field.
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Affiliation(s)
- Glenville Jones
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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Zou M, Baitei EY, Alzahrani AS, Parhar RS, Al-Mohanna FA, Meyer BF, Shi Y. Mutation prediction by PolyPhen or functional assay, a detailed comparison of CYP27B1 missense mutations. Endocrine 2011; 40:14-20. [PMID: 21604088 DOI: 10.1007/s12020-011-9489-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 05/05/2011] [Indexed: 01/08/2023]
Abstract
Vitamin D-dependent rickets type 1 (VDDR-I) is caused by mutation in CYP27B1. The glycine residue at codon 102 is not conserved between human (G(102)) and rodent (S(102)). G102E mutation results in 80% reduction in its enzymatic activity but PolyPhen predicts benign change. It is not known whether G102S has any damaging effect on 1α-hydroxylase activity. We investigated the effect of CYP27B1 (G102S) on its enzymatic activity and compared mutation prediction accuracy for all known CYP27B1 mutations among three free online protein prediction programs: PolyPhen, PolyPhen-2, and PSIPRED. G102S has no damaging effect on 1α-hydroxylase activity. G102D retained 30% enzymatic activity. All three programs correctly predicted damaging change for G102D. PolyPhen predicted benign change for G102S, whereas PolyPhen-2 and PSIPRED indicated possible damaging effect. Among 24 reported damaging mutations, PSIPRED, PolyPhen-2, and PolyPhen achieved 100%, 91.7% (22/24), and 75% (18/24) accuracy rate, respectively. The residues of incorrectly predicted mutations were not conserved. We conclude that G102D resulted in a significant reduction in 1α-hydroxylase activity, whereas G102S did not. PSIPRED and PolyPhen-2 are superior to PolyPhen in predicting damaging mutations.
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Affiliation(s)
- Minjing Zou
- Department of Genetics (MBC-03), King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
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Kim CJ. Vitamin D dependent rickets type I. KOREAN JOURNAL OF PEDIATRICS 2011; 54:51-4. [PMID: 21503197 PMCID: PMC3077501 DOI: 10.3345/kjp.2011.54.2.51] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 01/31/2011] [Indexed: 01/14/2023]
Abstract
Vitamin D is present in two forms, ergocalciferol (vitamin D2) produced by plants and cholecalciferol (vitamin D3) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D], plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of 1,25(OH)2D from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the 1α-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D 1α-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of 1,25(OH)2D despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human 1α-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and 1α-hydroxylase mutations with clinical findings.
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Affiliation(s)
- Chan Jong Kim
- Department of Pediatrics, Chonnam National University Medical School, Gwangju, Korea
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Vilchis F, Ramos L, Kofman-Alfaro S, Zenteno JC, Méndez JP, Chávez B. Extreme androgen resistance in a kindred with a novel insertion/deletion mutation in exon 5 of the androgen receptor gene. J Hum Genet 2003; 48:346-51. [PMID: 12908100 DOI: 10.1007/s10038-003-0036-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Accepted: 04/12/2003] [Indexed: 10/26/2022]
Abstract
Androgen insensitivy syndrome (AIS) is the most frequent cause of male pseudohermaphroditism resulting from target-organ resistance to androgen action. Individuals bearing the complete form of the disease (CAIS) present a female phenotype and a lack of pubic and axillary hair. In the present study, four 46,XY patients born in two generations from a kindred with a history of AIS were examined for genetic abnormalities in the androgen receptor gene (AR). All eight exons encoding the AR protein were individually amplified from genomic DNA followed by a mutation screening with single-strand conformation polymorphism analysis. Sequencing of the mutant AR revealed a novel insertion/deletion mutation in exon 5. A deletion of 7 bp is replaced by an insertion of 11 nucleotides, which represents a duplication of the adjacent downstream sequence. The mutation g.2640_2646delAGGATGC/2652_2662insTTCGCCCCTGA, results in a frameshift that introduces a premature termination signal TGA, nine codons downstream. Such a rearrangement predicts a truncation of the AR, thereby deleting a large portion of the ligand-binding domain (amino acid position 768-919). Furthermore, although this mutation breaks the translational reading frame starting from codon 760, examination of the complementary DNA suggested that it does not disturb mRNA splicing. These changes have been found in all the patients and appear to account for the observed absence of detectable androgen binding to the AR in cultured fibroblasts and for the CAIS phenotype in the kindred. This disorder represents the first insertion/deletion mutation of the AR that probably arose by a slipped-strand mispairing mechanism.
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Affiliation(s)
- Felipe Vilchis
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga 15, Tlalpan C.P. 14000, México D.F., México.
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Chen H, Hewison M, Hu B, Adams JS. Heterogeneous nuclear ribonucleoprotein (hnRNP) binding to hormone response elements: a cause of vitamin D resistance. Proc Natl Acad Sci U S A 2003; 100:6109-14. [PMID: 12716975 PMCID: PMC156334 DOI: 10.1073/pnas.1031395100] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2002] [Accepted: 03/10/2003] [Indexed: 01/15/2023] Open
Abstract
In previous studies, we have shown that steroid hormone resistance in New World primates occurs in the absence of abnormal expression of cognate nuclear receptors. Rather, these animals have elevated levels of heterogeneous nuclear ribonucleoproteins (hnRNPs) that act as hormone response element-binding proteins and attenuate target gene transactivation. Here we present evidence for a similar mechanism in humans via a patient with resistance to the active form of vitamin D [1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3))] who presented with normal vitamin D receptor (VDR) expression. Initial cotransfection studies showed that the cells of the patient suppressed basal and hormone-induced transactivation by wild-type VDR. Electrophoretic mobility-shift assays and Western/Southwestern blot analyses indicated that this suppressive effect was due to overexpression of a nuclear protein that specifically interacts with a DNA response element known to bind retinoid X receptor-VDR heterodimers. Ab blocking in electrophoretic mobility-shift assays indicated that this dominant-negative acting protein was in the hnRNPA family of nucleic acid-binding proteins. Further studies have shown that several members of this family, most notably hnRNPA1, were able to suppress basal and 1,25(OH)(2)D(3)-induced luciferase activity. We therefore propose that this case of vitamin D resistance in a human subject is similar to that previously described for New World primates in which abnormal expression of a hormone response element-binding protein can cause target cell resistance to 1,25(OH)(2)D(3). That this protein is a member of the hnRNP family capable of interacting with double-stranded DNA highlights a potentially important new component of the complex machinery required for steroid hormone signal transduction.
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Affiliation(s)
- Hong Chen
- Burns and Allen Research Institute and the Division of Endocrinology, Diabetes, and Metabolism, 8700 Beverly Boulevard, Room B-131, Los Angeles, CA 90048, USA
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