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Pecoraro C, Fioretti T, Perruno A, Klain A, Cioffi D, Ambrosio A, Passaro D, Annicchiarico Petruzzelli L, Di Domenico C, de Girolamo D, Vallone S, Cattaneo F, Ammendola R, Esposito G. De Novo Large Deletions in the PHEX Gene Caused X-Linked Hypophosphataemic Rickets in Two Italian Female Infants Successfully Treated with Burosumab. Diagnostics (Basel) 2023; 13:2552. [PMID: 37568915 PMCID: PMC10417872 DOI: 10.3390/diagnostics13152552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
Pathogenic variants in the PHEX gene cause rare and severe X-linked dominant hypophosphataemia (XLH), a form of heritable hypophosphatemic rickets (HR) characterized by renal phosphate wasting and elevated fibroblast growth factor 23 (FGF23) levels. Burosumab, the approved human monoclonal anti-FGF23 antibody, is the treatment of choice for XLH. The genetic and phenotypic heterogeneity of HR often delays XLH diagnoses, with critical effects on disease course and therapy. We herein report the clinical and genetic features of two Italian female infants with sporadic HR who successfully responded to burosumab. Their diagnoses were based on clinical and laboratory findings and physical examinations. Next-generation sequencing (NGS) of the genes associated with inherited HR and multiple ligation probe amplification (MLPA) analysis of the PHEX and FGF23 genes were performed. While a conventional analysis of the NGS data did not reveal pathogenic or likely pathogenic small nucleotide variants (SNVs) in the known HR-related genes, a quantitative analysis identified two different heterozygous de novo large intragenic deletions in PHEX, and this was confirmed by MLPA. Our molecular data indicated that deletions in the PHEX gene can be the cause of a significant fraction of XLH; hence, their presence should be evaluated in SNV-negative female patients. Our patients successfully responded to burosumab, demonstrating the efficacy of this drug in the treatment of XLH. In conclusion, the execution of a phenotype-oriented genetic test, guided by known types of variants, including the rarest ones, was crucial to reach the definitive diagnoses and ensure our patients of long-term therapy administration.
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Affiliation(s)
- Carmine Pecoraro
- Paediatric Nephrology, Dialysis and Renal Transplantation Unit, Santobono Pausilipon Children’s Hospital, 80129 Naples, Italy;
| | - Tiziana Fioretti
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
| | - Assunta Perruno
- Primary Care Pediatrician, ASL NA2 North, 80027 Naples, Italy;
| | - Antonella Klain
- Pediatric Endocrinology Unit, Santobono Pausilipon Children’s Hospital, 80129 Naples, Italy; (A.K.); (D.C.)
| | - Daniela Cioffi
- Pediatric Endocrinology Unit, Santobono Pausilipon Children’s Hospital, 80129 Naples, Italy; (A.K.); (D.C.)
| | - Adelaide Ambrosio
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
| | - Diego Passaro
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
| | - Luigi Annicchiarico Petruzzelli
- Paediatric Nephrology, Dialysis and Renal Transplantation Unit, Santobono Pausilipon Children’s Hospital, 80129 Naples, Italy;
| | - Carmela Di Domenico
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
| | - Domenico de Girolamo
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
| | - Sabrina Vallone
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, 80131 Naples, Italy; (S.V.); (F.C.); (R.A.)
| | - Fabio Cattaneo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, 80131 Naples, Italy; (S.V.); (F.C.); (R.A.)
| | - Rosario Ammendola
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, 80131 Naples, Italy; (S.V.); (F.C.); (R.A.)
| | - Gabriella Esposito
- CEINGE—Advanced Biotechnologies Franco Salvatore, 80145 Naples, Italy; (T.F.); (A.A.); (D.P.); (C.D.D.); (D.d.G.)
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, 80131 Naples, Italy; (S.V.); (F.C.); (R.A.)
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Zagari MC, Chiarello P, Iuliano S, D’Antona L, Rocca V, Colao E, Perrotti N, Greco F, Iuliano R, Aversa A. The Variant p.Ala84Pro Is Causative of X-Linked Hypophosphatemic Rickets: Possible Relationship with Burosumab Swinging Response in Adults. Genes (Basel) 2022; 14:genes14010080. [PMID: 36672821 PMCID: PMC9859156 DOI: 10.3390/genes14010080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/01/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Loss of function mutations in the PHEX gene could determine X-linked dominant hypophosphatemia. This is the most common form of genetic rickets. It is characterized by renal phosphate wasting determining an increase in fibroblast growth factor 23 (FGF-23), growth retard, bone deformities and musculoskeletal manifestations. In recent decades, analysis of the PHEX gene has revealed numerous different mutations. However, no clear genotype-phenotype correlations have been reported in patients with hypophosphatemic rickets (XLH). We report two cases of a 28-year-old-male (patient 1) and a 19-year-old male (patient 2) affected by XLH initially treated with phosphate and 1,25-dihydroxyvitamin-D admitted to the Endocrinology unit because of the persistence of muscle weakness, bone pain and fatigue. After phosphate withdrawal, both patients started therapy with burosumab and symptoms ameliorated in three months. However, patient 1's biochemical parameters did not improve as expected so we decided to investigate his genetic asset. We herein describe a possible clinical implication for the missense "de novo" mutation, c.250G>C (p.Ala84Pro) in the PHEX gene, reported in the PHEX database and classified as a variant of uncertain significance (VUS). The clinical implication of this mutation on disease burden and quality of life in adults is still under investigation.
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Affiliation(s)
- Maria Carmela Zagari
- Endocrinology Rare Disease Unit, Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, 88100 Catanzaro, Italy
| | - Paola Chiarello
- Department of Pediatrics, Pugliese-Ciaccio Hospital, Catanzaro, 88100 Catanzaro, Italy
- Department of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, 88100 Catanzaro, Italy
| | - Stefano Iuliano
- Endocrinology Rare Disease Unit, Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, 88100 Catanzaro, Italy
| | - Lucia D’Antona
- Department of Health Sciences, Magna Græcia University of Catanzaro, 88100 Catanzaro, Italy
| | - Valentina Rocca
- Endocrinology Rare Disease Unit, Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, 88100 Catanzaro, Italy
| | - Emma Colao
- Medical Genetics Unit, Mater Domini University Hospital, Catanzaro, 88100 Catanzaro, Italy
| | - Nicola Perrotti
- Department of Health Sciences, Magna Græcia University of Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, Mater Domini University Hospital, Catanzaro, 88100 Catanzaro, Italy
| | - Francesca Greco
- Endocrinology Rare Disease Unit, Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, 88100 Catanzaro, Italy
- Department of Human Movement Sciences and Health, University of Rome “Foro Italico”, 00135 Rome, Italy
| | - Rodolfo Iuliano
- Department of Health Sciences, Magna Græcia University of Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, Mater Domini University Hospital, Catanzaro, 88100 Catanzaro, Italy
- Correspondence: (R.I.); (A.A.)
| | - Antonio Aversa
- Endocrinology Rare Disease Unit, Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, 88100 Catanzaro, Italy
- Correspondence: (R.I.); (A.A.)
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Tavana N, Ting TH, Lai K, Kennerson ML, Thilakavathy K. Whole exome sequencing identifies two novel variants in PHEX and DMP1 in Malaysian children with hypophosphatemic rickets. Ital J Pediatr 2022; 48:193. [PMID: 36482408 PMCID: PMC9730657 DOI: 10.1186/s13052-022-01385-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Hypophosphatemic rickets (HR) is a genetic disease of phosphate wasting that is characterized by defective bone mineralization. The most common cause of the disease is mutations in the phosphate regulating gene with homologies to endopeptidases on the X chromosome (PHEX) gene. The aims of this study were to identify the gene variants responsible for HR in three cases of Malaysian origin from three independent families and to describe their clinical, biochemical, and radiological features. METHODS Whole exome sequencing (WES) was performed on all patients and their parents, followed by Sanger sequencing validation. Bioinformatics tools were used to provide supporting evidence for pathogenicity of variants. To confirm that a mutation is de novo, paternity test was carried out. High resolution melting curve analysis was performed to assess the allele frequency in normal controls for mutations that were found in the patients. RESULTS The patients showed typical characteristics of HR including lower limb deformity, hypophosphatemia, and elevated alkaline phosphatase. WES revealed two variants in the PHEX gene and one variant in the dentin matrix protein 1 (DMP1) gene. Two of the three variants were novel, including c.1946_1954del (p.Gly649_Arg651del) in PHEX and c.54 + 1G > A in DMP1. Our data suggests that the novel p.Gly649_Arg651del variant is likely pathogenic for HR disease. CONCLUSIONS This study extends the variant spectrum of the PHEX and DMP1 genes. Our findings indicate that WES is an advantageous approach for diagnosis of genetic diseases which are heterogeneous.
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Affiliation(s)
- Nahid Tavana
- grid.11142.370000 0001 2231 800XDepartment of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia
| | - Tzer Hwu Ting
- grid.11142.370000 0001 2231 800XDepartment of Paediatrics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia
| | - Kaitao Lai
- grid.1013.30000 0004 1936 834XNorthcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW Australia ,grid.1013.30000 0004 1936 834XSydney Medical School, University of Sydney, Sydney, NSW Australia
| | - Marina L. Kennerson
- grid.1013.30000 0004 1936 834XNorthcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW Australia ,grid.414685.a0000 0004 0392 3935Molecular Medicine Laboratory, Concord Hospital, Concord, NSW Australia
| | - Karuppiah Thilakavathy
- grid.11142.370000 0001 2231 800XDepartment of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia ,grid.11142.370000 0001 2231 800XGenetics and Regenerative Medicine Research Group, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia
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Pathogenic Variants of the PHEX Gene. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Twenty-five years ago, a pathogenic variant of the phosphate-regulating endopeptidase homolog X-linked (PHEX) gene was identified as the cause of X-linked hypophosphatemic rickets (XLH). Subsequently, the overproduction of fibroblast growth factor 23 (FGF23) due to PHEX defects has been found to be associated with XLH pathophysiology. However, the mechanism by which PHEX deficiency contributes to the upregulation of FGF23 and the function of PHEX itself remain unclear. To date, over 700 pathogenic variants have been identified in patients with XLH, and functional assays and genotype–phenotype correlation analyses based on pathogenic variant data derived from XLH patients have been reported. Genetic testing for XLH is useful for the diagnosis. Not only have single-nucleotide variants causing missense, nonsense, and splicing variants and small deletion/insertion variants causing frameshift/non-frameshift alterations been observed, but also gross deletion/duplication variants causing copy number variants have been reported as pathogenic variants in PHEX. With the development of new technologies including next generation sequencing, it is expected that an increasing number of pathogenic variants will be identified. This chapter aimed to summarize the genotype of PHEX and related analyses and discusses the pathophysiology of PHEX defects to seek clues on unsolved questions.
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Cao Y, You Y, Wang Q, Ren X, Li S, Li L, Xia W, Guan X, Yang T, Ikegawa S, Wang Z, Zhao X. Identification of six novel variants from nine Chinese families with hypophosphatemic rickets. BMC Med Genomics 2022; 15:161. [PMID: 35842615 PMCID: PMC9287957 DOI: 10.1186/s12920-022-01305-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/27/2022] [Indexed: 11/25/2022] Open
Abstract
Background Hypophosphatemic rickets (HR) is a rare genetic disorder associated with renal phosphate wasting and characterized by bone defects. Inactivating mutations in the phosphate regulating endopeptidase homolog X‑linked gene (PHEX) account for most cases of HR. The aim of this study was to identify causative variants in nine unrelated Chinese families associated with HR, and to determine potential pathogenicity of the identified variants. Methods Genomic DNA was isolated from the peripheral blood of HR patients and their healthy relatives, followed by next-generation sequencing and/or Sanger sequencing. In silico prediction combined with conservation analysis was performed to assess the effects of the variants, and 3D protein modeling was conducted to predict the functional effects on the encoded protein. Results All HR patients recruited in this study displayed bone deformities and tooth agenesis, as well as reduced serum phosphate levels and elevated urine phosphate levels. Nine PHEX variants were identified in eight families, including four novel variants (c.1661_1726del, c.980A > G, c.1078A > T, and c.1017_1051dup). Of the nine identified PHEX variants, five caused a truncated protein, two caused an altered amino acid, and the other two were the canonical splicing variants. Novel variants c.1336G > A and c.1364 T > C in SLC34A3 were also found in one family. Conservation analysis showed that all the amino acids corresponding to the missense variants were highly conserved. In silico analysis and 3D protein structure modeling confirmed the pathogenicity of these variants. Conclusions This study identified four novel variants in PHEX and two novel variants in SLC34A3 in a Chinese cohort with HR. Our findings highlight the dominant role of PHEX in HR, and expand the genotypic and phenotypic spectra of this disorder. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-022-01305-w.
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Affiliation(s)
- Yixuan Cao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Yi You
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Qiong Wang
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Xiuzhi Ren
- The People's Hospital of Wuqing District, Tianjin, 301700, China
| | - Shan Li
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Lulu Li
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology of the Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, 100730, China
| | - Xin Guan
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Tao Yang
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Shiro Ikegawa
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences (IMS), Tokyo, 108-8639, Japan
| | - Zheng Wang
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences (IMS), Tokyo, 108-8639, Japan
| | - Xiuli Zhao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
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Function of PHEX mutations p.Glu145* and p.Trp749Arg in families with X-linked hypophosphatemic rickets by the negative regulation mechanism on FGF23 promoter transcription. Cell Death Dis 2022; 13:518. [PMID: 35654784 PMCID: PMC9163062 DOI: 10.1038/s41419-022-04969-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 01/21/2023]
Abstract
X-linked hypophosphatemic rickets (XLH) is characterized by increased circulating fibroblast growth factor 23 (FGF23) concentration caused by PHEX (NM_000444.5) mutations. Renal tubular resorption of phosphate is impaired, resulting in rickets and impaired bone mineralization. By phenotypic-genetic linkage analysis, two PHEX pathogenic mutations were found in two XLH families: c.433 G > T, p.Glu145* in exon 4 and c.2245 T > C, p.Trp749Arg in exon 22. Immunofluorescence showed that the localization of p.Glu145* and p.Trp749Arg mutant and secretory PHEX (secPHEX) changed, with decreased expression. In a HEK293T cell model co-transfected with PHEX, secPHEX, and FGF23, wild-type PHEX, secPHEX, and FGF23 proteins were distributed in the cell membrane or endoplasmic reticulum, while the mutant was located in the nuclear membrane and cytoplasm. qPCR of p.Glu145* revealed decreased PHEX and secPHEX mRNA expression in cells, with no difference in mRNA expression of p.Trp749Arg. Both mutations decreased intracellular PHEX endopeptidase activity. Western blot analysis showed decrease in mutant and secPHEX protein expression and no FGF23 protein expression in single-transfected PHEX and secPHEX cells. In cells co-transfected with FGF23, PHEX and secPHEX mutation promoted FGF23 expression. Dual-luciferase reporter gene was used to detect the effect of PHEX on FGF23 promoter. The dual-luciferase reporter gene showed that after PHEX overexpression, the activity of mutant firefly luciferase was significantly higher than that of wild type. The regulatory mechanism between PHEX and FGF23 is still unclear, but we found that PHEX is a direct transcriptional inhibitor of FGF23 and affects the expression of FGF23. This study verified the pathogenicity of the two variants and revealed the possible regulatory mechanism between PHEX and FGF23.
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Xu T, Tao X, Zhang Z, Yue H. Clinical and genetic characteristics of 29 Chinese patients with X-linked hypophosphatemia. Front Endocrinol (Lausanne) 2022; 13:956646. [PMID: 36060934 PMCID: PMC9437435 DOI: 10.3389/fendo.2022.956646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/02/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE The aim of this study was to fully describe the clinical and genetic characteristics, including clinical manifestations, intact fibroblast growth factor 23 (iFGF23) levels, and presence of PHEX gene mutations, of 22 and 7 patients with familial and sporadic X-linked dominant hypophosphatemia (XLH), respectively. METHODS Demographic data, clinical features, biochemical indicators, and imaging data of 29 patients were collected. All 22 exons and exon-intron boundaries of the PHEX gene were amplified by polymerase chain reaction (PCR) and directly sequenced. The serum level of iFGF23 was measured in 15 of the patients. RESULTS Twenty-nine patients (male/female: 13:16, juvenile/adult: 15:14) with XLH were included. The main symptoms were bowed lower extremities (89.7%), abnormal gait (89.7%), and short stature/growth retardation (78.6%). Hypophosphatemia with a high alkaline phosphatase level was the main biochemical feature and the median value of serum iFGF23 was 55.7 pg/ml (reference range: 16.1-42.2 pg/ml). Eight novel mutations in the PHEX gene were identified by Sanger sequencing, including two missense mutations (p. Gln682Leu and p. Phe312Ser), two deletions (c.350_356del and c.755_761del), one insertion (c.1985_1986insTGAC), and three splice mutations (c.1700+5G>C, c.1966-1G>T, and c.350-14_350-1del). Additionally, the recurrence rate after the first orthopedic surgery was 77.8% (7/9), and five of them had their first surgery before puberty. CONCLUSION Our study expanded the clinical phenotypes and gene mutation spectrum of XLH and provided a reference for the optimal timing of orthopedic surgeries.
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Affiliation(s)
| | | | | | - Hua Yue
- *Correspondence: Hua Yue, ; Zhenlin Zhang,
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Cavaco D, Amaro P, Simões-Pereira J, Pereira MC. X-Linked Hypophosphatemic Rickets: Report of a Novel PHEX Mutation and Cinacalcet as Adjuvant Therapy in the Mineral Metabolism Control. Mod Rheumatol Case Rep 2021; 6:145-149. [PMID: 34561702 DOI: 10.1093/mrcr/rxab031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/24/2021] [Accepted: 09/01/2021] [Indexed: 12/24/2022]
Abstract
X-linked hypophosphatemic rickets (XLH) is a rare disease caused by a mutation in the PHEX gene, located on the X chromosome. This gene encodes the phosphate regulating endopeptidase, and its inactivation leads to increased levels of circulating phosphatonins responsible for renal phosphate loss. The treatment of XLH is still carried out with long-term administration of phosphate and calcitriol, which can be complicated by hyperparathyroidism, nephrocalcinosis, renal failure and hypertension. We describe the case of a four-decades follow-up patient with XLH. When she was diagnosed, at 19, due to bone pain and deformities, she was put on therapy with phosphorus and cholecalciferol. Despite the clinical improvement, serum phosphorus remained difficult to control. At the age of 44, she developed tertiary hyperparathyroidism and was submitted to parathyroidectomy. Five years later, parathyroid hyperfunction recurred. This time, cinacalcet was started, 30 mg alternating with 60 mg/day. Currently, she is 59 years-old and remains with controlled mineral metabolism. The genetic study of this patient revealed a nonsense heterozygous mutation (c.501G> A) in PHEX gene that was not previously described. In this case, the off-label use of cinacalcet resulted in the normalization of serum PTH and phosphorus levels, eliminated recurrent secondary hyperparathyroidism, which aggravates the bone fragility inherent to XLH and prevented a new parathyroidectomy. This report also adds important information to the genetic basis of XLH with the identification of a new nonsense mutation of the PHEX gene.
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Affiliation(s)
- Daniela Cavaco
- Department of Endocrinology, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal
| | - Pedro Amaro
- Department of Orthopaedic Surgery, Hospital Beatriz Ângelo, Lisbon, Portugal
| | - Joana Simões-Pereira
- Department of Endocrinology, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal.,NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Maria Conceição Pereira
- Department of Endocrinology, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal
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Lin X, Li S, Zhang Z, Yue H. Clinical and Genetic Characteristics of 153 Chinese Patients With X-Linked Hypophosphatemia. Front Cell Dev Biol 2021; 9:617738. [PMID: 34141703 PMCID: PMC8204109 DOI: 10.3389/fcell.2021.617738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/16/2021] [Indexed: 11/27/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is caused by inactivating mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX) gene, resulting in an excess of circulating intact fibroblast growth factor-23 (iFGF-23) and a waste of renal phosphate. In the present study, we retrospectively reviewed the clinical and molecular features of 153 Chinese patients, representing 87 familial and 66 sporadic cases with XLH. A total of 153 patients with XLH presented with signs or symptoms at a median age of 18.0 months (range, 9.0 months–26.0 years). Lower-limb deformity was the most frequent clinical manifestation, accounting for 79.1% (121/153). Biochemical screening showed increased serum levels of iFGF23 in patients with XLH, with a wide variation ranging from 14.39 to 730.70 pg/ml. Median values of serum iFGF23 in pediatric and adult patients were 94.87 pg/ml (interquartile range: 74.27–151.86 pg/ml) and 72.82 pg/ml (interquartile range: 39.42–136.00 pg/ml), respectively. Although no difference in circulating iFGF23 levels between these two groups was observed (P = 0.062), the proportion of patients with high levels of circulating iFGF23 (>42.2 pg/ml) was greater in the pediatric group than in the adult group (P = 0.026). Eighty-eight different mutations in 153 patients were identified, with 27 (30.7%) being novel. iFGF23 levels and severity of the disease did not correlate significantly with truncating and non-truncating mutations or N-terminal and C-terminal PHEX mutations. This study provides a comprehensive description of the clinical profiles, circulating levels of iFGF23 and gene mutation features of patients with XLH, further enriching the genotypic spectrum of the diseases. The findings show no evident correlation of circulating iFGF23 levels with the age or disease severity in patients with XLH.
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Affiliation(s)
- Xiaoyun Lin
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Shanshan Li
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Zhenlin Zhang
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Hua Yue
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
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Jeong IH, Yoo JH, Kim N. A pathogenic PHEX variant (c.1483-1G>C) in a Korean patient with X-linked hypophosphatemic rickets. Ann Pediatr Endocrinol Metab 2021; 26:130-133. [PMID: 34218635 PMCID: PMC8255857 DOI: 10.6065/apem.2040186.093] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 11/28/2022] Open
Abstract
X-linked hypophosphatemic rickets is an X-linked dominantly inherited disorder characterized by defects in renal phosphate transport leading to phosphate wasting and hypophosphatemia. In this report, we describe a case of X-linked hypophosphatemic rickets in a patient with a rare pathogenic PHEX variant. The 25-year-old female patient came to our clinic for genetic counseling regarding presumed genetic disease and pregnancy. When she was 9 years old, she had been diagnosed with vitamin D-resistant rickets based on laboratory results and symptoms. She had undergone orthopedic surgery due to bowing leg deformities. Since then, she was intermittently self-prescribing oral phosphate and calcium supplements. At 25 years old, she was diagnosed with X-linked hypophosphatemic rickets with a rare pathogenic PHEX variant (c.1483-1G>C) by next-generation sequencing. This is the second report of the c.1483-1G>C variant to date, and her pathogenicity was confirmed based on the most recent guideline. Traditionally, the disease had been diagnosed mostly based on clinical findings. However, with advancements in genetic testing, genetic confirmation has become an imperative part of diagnostic workup. Herein, we report a 25-year-old female Korean patient diagnosed with X-linked hypophosphatemic rickets harboring a rare pathogenic PHEX variant.
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Affiliation(s)
- In Hwa Jeong
- Department of Laboratory Medicine, Dong-A University Hospital, Busan, Korea
| | - Jae-Ho Yoo
- Department of Pediatrics, Dong-A University Hospital, Busan, Korea
| | - Namhee Kim
- Department of Laboratory Medicine, Dong-A University Hospital, Busan, Korea,Address for correspondence: Namhee Kim Department of Laboratory Medicine, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan 49201, Korea
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11
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Diagnosis and management of X-linked hypophosphatemia in children and adolescent in the Gulf Cooperation Council countries. Arch Osteoporos 2021; 16:52. [PMID: 33660084 PMCID: PMC7929956 DOI: 10.1007/s11657-021-00879-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/04/2021] [Indexed: 02/03/2023]
Abstract
INTRODUCTION X-linked hypophosphatemia (XLH) is a rare inherited cause of hypophosphatemic rickets and osteomalacia. It is caused by mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX). This results in increased plasma fibroblast growth factor-23 (FGF23), which leads to loss of renal sodium-phosphate co-transporter expression leading to chronic renal phosphate excretion. It also leads to low serum 1,25-dihydroxyvitamin D (1,25(OH)2D), resulting in impaired intestinal phosphate absorption. Chronic hypophosphatemia in XLH leads to impaired endochondral mineralization of the growth plates of long bones with bony deformities. XLH in children and adolescents also causes impaired growth, myopathy, bone pain, and dental abscesses. XLH is the most frequent inherited cause of phosphopenic rickets/osteomalacia. Hypophosphatemia is also found in calcipenic rickets/osteomalacia as a result of secondary hyperparathyroidism. Thus, chronic hypophosphatemia is a common etiologic factor in all types of rickets. RESULTS There is considerable overlap between symptoms and signs of phosphopenic and calcipenic rickets/osteomalacia. Wrong diagnosis leads to inappropriate treatment of rickets/osteomalacia. Nutritional rickets and osteomalacia are common in the Gulf Cooperation Council countries which include Saudi Arabia, United Arab Emirates, Kuwait, Qatar, Bahrain, and Oman. Due to high levels of consanguinity in the region, genetic causes of phosphopenic and calcipenic rickets/osteomalacia are also common. CONCLUSION This guideline was developed to provide an approach to the diagnosis of XLH, especially where there is no family history of the disease, and that other related conditions are not mistaken for XLH. We also guide the medical management of XLH with conventional treatment and with burosumab, a recombinant human IgG1 monoclonal antibody to FGF23.
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Lin Y, Xu J, Li X, Sheng H, Su L, Wu M, Cheng J, Huang Y, Mao X, Zhou Z, Zhang W, Li C, Cai Y, Wu D, Lu Z, Yin X, Zeng C, Liu L. Novel variants and uncommon cases among southern Chinese children with X-linked hypophosphatemia. J Endocrinol Invest 2020; 43:1577-1590. [PMID: 32253725 DOI: 10.1007/s40618-020-01240-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/24/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE X-linked hypophosphatemia (XLH) is the most common inherited renal phosphate wasting disorder and is often misdiagnosed as vitamin D deficiency. This study aims to provide clinical and mutational characteristics of 65 XLH pediatric patients in southern China. METHODS In this work, a combination of DNA sequencing and qPCR analysis was used to study the PHEX gene in 80 pediatric patients diagnosed with hypophosphatemia. The clinical and laboratory data of confirmed 65 XLH patients were assessed and analyzed retrospectively. RESULTS In 65 XLH patients from 61 families, 51 different variants in the PHEX gene were identified, including 23 previously reported variants and 28 novel variants. In this cohort of XLH patients, the c.1601C>T(p.Pro534Leu) variant appears more frequently. Fourteen uncommon XLH cases were described, including four boys with de novo mosaic variants, eight patients with large deletions and a pair of monozygotic twins. The clinical manifestations in this cohort are very similar to those previously reported. CONCLUSION This study extends the mutational spectrum of the PHEX gene, which will contribute to accurate diagnosis. This study also suggests a supplementary qPCR or MLPA assay may be performed along with classical sequencing to confirm the gross insertion/deletion.
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Affiliation(s)
- Y Lin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - J Xu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - X Li
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - H Sheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - L Su
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - M Wu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - J Cheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Y Huang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - X Mao
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Z Zhou
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - W Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - C Li
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Y Cai
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - D Wu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Z Lu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - X Yin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - C Zeng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China.
| | - L Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China.
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Forero-Delgadillo JM, Cleves D, Ochoa V, Londoño-Correa H, Restrepo JM, Nastasi-Catanese JA, Pachajoa H. PHEX Gene Mutation in a Patient with X-Linked Hypophosphatemic Rickets in a Developing Country. Appl Clin Genet 2020; 13:57-62. [PMID: 32104046 PMCID: PMC7025672 DOI: 10.2147/tacg.s232448] [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: 09/25/2019] [Accepted: 12/23/2019] [Indexed: 12/03/2022] Open
Abstract
Introduction X-linked hypophosphatemic rickets is part of a larger group of hereditary diseases characterized by renal phosphate loss, which causes growth disorders, rickets, and osteomalacia. These conditions are characterized by disorders in phosphate equilibrium, which is essential for bone formation. Case Report A female patient presented with bone deformities of the inferior extremities, prominent joints, and loss of teeth. She received initial management with oral calcium and orthotics in inferior extremities, with poor clinical outcome. PHEX gene sequencing revealed a pathogenic variant c.1601C>T (p.Pro534Leu). Discussion XLHR is caused by mutations in the PHEX gene; to date, more than 460 mutations have been associated with the disease. Clinically, it is characterized by bowing of the lower extremities, decreased growth, musculoskeletal complaints, dental abscesses, and other clinical signs and symptoms of rickets.
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Affiliation(s)
- Jessica María Forero-Delgadillo
- Pediatric Nephrology Fellow, Universidad Icesi-Fundación Valle de Lili, Cali, Colombia.,Facultad de Ciencias de la Salud, Universidad Icesi, Cali, Colombia
| | - Daniela Cleves
- Facultad de Ciencias de la Salud, Universidad Icesi, Cali, Colombia.,Pediatrics Resident, Universidad Icesi-Fundación Valle de Lili, Cali, Colombia
| | - Vanessa Ochoa
- Pediatric Nephrology Fellow, Universidad Icesi-Fundación Valle de Lili, Cali, Colombia.,Facultad de Ciencias de la Salud, Universidad Icesi, Cali, Colombia
| | | | | | - José Antonio Nastasi-Catanese
- Pediatric Nephrology Department, Fundación Valle del Lili, Cali, Colombia.,Clinical Genetics Department, Fundación Valle del Lili, Cali, Colombia
| | - Harry Pachajoa
- Facultad de Ciencias de la Salud, Universidad Icesi, Cali, Colombia.,Clinical Genetics Department, Fundación Valle del Lili, Cali, Colombia
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Rothenbuhler A, Schnabel D, Högler W, Linglart A. Diagnosis, treatment-monitoring and follow-up of children and adolescents with X-linked hypophosphatemia (XLH). Metabolism 2020; 103S:153892. [PMID: 30928313 DOI: 10.1016/j.metabol.2019.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 11/19/2022]
Abstract
Early diagnosis, optimal therapeutic management and regular follow up of children with X-linked hypophosphatemia (XLH) determine their long term outcomes and future quality of life. Biochemical screening of potentially affected newborns in familial cases and improving physician's knowledge on clinical signs, symptoms and biochemical characteristics of XLH for de novo cases should lead to earlier diagnosis and treatment initiation. The follow-up of children with XLH includes clinical, biochemical and radiological monitoring of treatment (efficacy and complications) and screening for XLH-related dental, neurosurgical, rheumatological, cardiovascular, renal and ENT complications. In 2018, the European Union approved the use of burosumab, a humanized monoclonal anti-FGF23 antibody, as an alternative therapy to conventional therapy (active vitamin D analogues and phosphate supplements) in growing children with XLH and insufficiently controlled disease. Diagnostic criteria of XLH and the principles of disease management with conventional treatment or with burosumab are reviewed in this paper.
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Affiliation(s)
- Anya Rothenbuhler
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France; APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, Paris, France; APHP, Platform of Expertise for Rare Disorders Paris-Sud, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France.
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charité, University Medicine Berlin, Germany
| | - Wolfgang Högler
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Department of Pediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Agnès Linglart
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France; APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, Paris, France; APHP, Platform of Expertise for Rare Disorders Paris-Sud, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France
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15
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Zhang C, Zhao Z, Sun Y, Xu L, JiaJue R, Cui L, Pang Q, Jiang Y, Li M, Wang O, He X, He S, Nie M, Xing X, Meng X, Zhou X, Yan L, Kaplan JM, Insogna KL, Xia W. Clinical and genetic analysis in a large Chinese cohort of patients with X-linked hypophosphatemia. Bone 2019; 121:212-220. [PMID: 30682568 DOI: 10.1016/j.bone.2019.01.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/11/2019] [Accepted: 01/20/2019] [Indexed: 01/09/2023]
Abstract
X-linked Hypophosphatemia (XLH) is caused by loss of function mutations in the PHEX gene. Given the recent availability of a new therapy for XLH, a retrospective analysis of the most recent 261 Chinese patients with XLH evaluated at Peking Union Medical College Hospital was conducted. Clinical, biochemical, radiographic studies, as well as genetic analyses, including Sanger sequencing for point mutations and Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large deletions/duplications were employed. Based on the structure of Neprilysin (NEP), a member of M13 family that includes PHEX, a three-dimensional (3D) model of PHEX was constructed, missense and nonsense mutations were positioned on the predicted structure to visualize relative positions of these two types of variants. Sex differences and genotype-phenotype correlations were also undertaken. Genetic analyses identified 166 PHEX mutations in 261 XLH patients. One hundred and eleven of the 166 mutations were unreported. Four mutational 'hot-spots' were identified in this cohort (P534L, G579R, R747X, c.1645+1 G>A). Missense mutations, but not nonsense mutations, clustered in the two putative lobes of the PHEX protein, suggesting these are functionally important regions of the molecule. Circulating levels of intact FGF23 were significantly elevated (median level 101.9 pg/mL; reference range 16.1-42.2 pg/mL). No significant sex differences, as well as no phenotypic differences were identified between patients with putative truncating and non-truncating PHEX mutations. However, patients with N-terminal PHEX mutations had an earlier age of onset of disease (P = 0.015) and higher iFGF23 levels (P = 0.045) as compared to those with C-terminal mutations. These data provide a comprehensive characterization of the largest cohort of patients with XLH reported to date from China, which will help in evaluating the applicability of emerging therapies for this disease in this ethnic group.
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Affiliation(s)
- Cong Zhang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Zhen Zhao
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China; Department of Geriatrics, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing 100050, China
| | - Yue Sun
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Lijun Xu
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Ruizhi JiaJue
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Lijia Cui
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Qianqian Pang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Mei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Ou Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Xiaodong He
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China; Department of Endocrinology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China
| | - Shuli He
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Min Nie
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Xiaoping Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Xunwu Meng
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Xueying Zhou
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Lina Yan
- Department of Endocrinology, Baogang Hospital, Baotou, Inner Mongolia 014000, China
| | - Jared M Kaplan
- Department of Medicine, Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Karl L Insogna
- Department of Medicine, Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China.
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Gu J, Wang C, Zhang H, Yue H, Hu W, He J, Fu W, Zhang Z. Targeted resequencing of phosphorus metabolism‑related genes in 86 patients with hypophosphatemic rickets/osteomalacia. Int J Mol Med 2018; 42:1603-1614. [PMID: 29901142 DOI: 10.3892/ijmm.2018.3730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/08/2018] [Indexed: 11/05/2022] Open
Abstract
Hypophosphatemic rickets/osteomalacia is characterized by defective renal phosphate reabsorption and abnormal bone mineralization. Hypophosphatemic rickets/osteomalacia consists of inherited and acquired forms, many of which have unknown aetiology. In the present study, next‑generation sequencing‑based resequencing was used on samples from Chinese subjects with hypophosphatemic rickets/osteomalacia, aiming to detect the spectrum of pathogenic genes in these patients. A total of 86 hypophosphatemic rickets/osteomalacia patients (ranging from 3 to 70 years old) were recruited. Patients with tumour‑induced osteomalacia (TIO), renal tubular acidosis, renal osteodystrophy, and adefovir‑induced Fanconi syndrome were excluded. Targeted massively parallel resequencing of 196 candidate genes for hypophosphatemic rickets/osteomalacia was performed in the 86 affected unrelated individuals (cases) and in 100 unrelated healthy controls to identify new genes and mutations in known genes that cause hypophosphatemic rickets/osteomalacia. The results identified seven phosphate‑regulating gene with homologies to endopeptidases on the X chromosome (PHEX) mutations (of which two were novel) and one novel dentin matrix protein 1 (DMP1) mutation in eight patients. Following targeted exome sequencing data analysis, 14 candidate disease‑related gene loci were selected, two of which were of most concern regarding disease severity. Further validation of the present results is warranted, with additional sequencing projects and functional tests. To our knowledge, the present study is the largest cohort of cases with hypophosphatemic rickets/osteomalacia to undergo targeted resequencing. The diagnosis and understanding of the molecular aetiologies of these disorders will be improved by this fast and efficient approach.
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Affiliation(s)
- Jiemei Gu
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Chun Wang
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Hao Zhang
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Hua Yue
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Weiwei Hu
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Jinwei He
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Wenzhen Fu
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Zhenlin Zhang
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
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Marik B, Bagga A, Sinha A, Hari P, Sharma A. Genetics of Refractory Rickets: Identification of Novel PHEX Mutations in Indian Patients and a Literature Update. J Pediatr Genet 2018; 7:47-59. [PMID: 29707405 PMCID: PMC5916800 DOI: 10.1055/s-0038-1624577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/25/2017] [Indexed: 10/18/2022]
Abstract
Refractory rickets is a genetic disorder that cannot be treated by vitamin D supplementation and adequate dietary calcium and phosphorus. Hereditary hypophosphatemic rickets is one of the major forms of refractory rickets in Indian children and caused due to mutations in the PHEX , FGF23 , DMP1 , ENPP1 , and SLC34A3 genes. This is the first study in India on a large number of patients reporting on mutational screening of the PHEX gene. Direct sequencing in 37 patients with refractory rickets revealed eight mutations in 13 patients of which 1 was nonsense, 2 were deletions, 1 was a deletion-insertion, and 4 were missense mutations. Of these mutations, four (c.566_567 delAG, c.651_654delACAT, c.1337delinsAATAA, and c.2048T > A) were novel mutations. This article discusses the mutations in Indian patients, collates information on the genetic causes of refractory rickets, and emphasizes the significance of genetic testing for precise diagnosis, timely treatment, and management of the condition, especially in developing countries.
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Affiliation(s)
- Binata Marik
- Division of Genetics, Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Arvind Bagga
- Department of Paediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Aditi Sinha
- Department of Paediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Hari
- Department of Paediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Arundhati Sharma
- Division of Genetics, Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
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Michałus I, Rusińska A. Rare, genetically conditioned forms of rickets: Differential diagnosis and advances in diagnostics and treatment. Clin Genet 2018; 94:103-114. [DOI: 10.1111/cge.13229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 12/21/2022]
Affiliation(s)
- I. Michałus
- Department of Propedeutics Pediatrics and Bone Metabolic Diseases; Medical University of Lodz; Lodz Poland
| | - A. Rusińska
- Department of Propedeutics Pediatrics and Bone Metabolic Diseases; Medical University of Lodz; Lodz Poland
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Vidmar AP, Miyazaki B, Sanchez-Lara PA, Pitukcheewanont P. X-linked Hypophosphatemic Rickets, del(2)(q37.1;q37.3) Deletion Syndrome and Mosaic Turner Syndrome, mos 45,X/46,X, del(2)(q37.1;q37.3) in a 3-year-old Female. J Bone Metab 2017; 24:257-261. [PMID: 29259966 PMCID: PMC5734952 DOI: 10.11005/jbm.2017.24.4.257] [Citation(s) in RCA: 4] [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: 10/10/2017] [Revised: 11/16/2017] [Accepted: 11/18/2017] [Indexed: 01/03/2023] Open
Abstract
There are currently no published cases that report concomitant Turner syndrome (TS), 2q37 deletion syndrome and X-linked hypophosphatemic rickets (XLH). Interestingly, since the clinical phenotypes of TS and 2q37 deletion syndrome overlap, the correct diagnosis may be missed without a standardized approach to genetic testing consisting of both karyotype and microarray. Both chromosome anomalies have been associated with short stature and a variety of skeletal abnormalities however to date no reports have associated these syndromes in association with a phosphate regulating endopeptidase homolog, X-linked (PHEX) gene deletion resulting in XLH. We report a 3-year-old female with 3 concurrent genetic disorders including a 9.98 Mb terminal deletion of chromosome 2: del(2)(q37.1;q37.3), XLH secondary to a small microdeletion of part of the PHEX gene, and mosaic TS (mos 45,X[32]/46,X[18]). This is the first case report of a patient with 2q37 deletion syndrome and mosaic TS (mos 45,X[32]/46,X[18]) found to have XLH secondary to an interstitial constitutional PHEX gene deletion. Her severe phenotype and multiple genotypic findings reinforce the importance of thorough genetic testing in the setting of complicated phenotypic presentations.
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Affiliation(s)
- Alaina P Vidmar
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Brian Miyazaki
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Pedro A Sanchez-Lara
- Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Pisit Pitukcheewanont
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
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Asadzadeh Manjili F, Bakhshi Aliabad MH, Kalantar SM, Sahebzamani A, Safa A. Molecular and Biochemical Aspects of Hypophosphatemic Rickets; an Updated Review. INTERNATIONAL JOURNAL OF BASIC SCIENCE IN MEDICINE 2017. [DOI: 10.15171/ijbsm.2017.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Coyac BR, Hoac B, Chafey P, Falgayrac G, Slimani L, Rowe PS, Penel G, Linglart A, McKee MD, Chaussain C, Bardet C. Defective Mineralization in X-Linked Hypophosphatemia Dental Pulp Cell Cultures. J Dent Res 2017; 97:184-191. [PMID: 28880715 DOI: 10.1177/0022034517728497] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is a skeletal disease caused by inactivating mutations in the PHEX gene. Mutated or absent PHEX protein/enzyme leads to a decreased serum phosphate level, which cause mineralization defects in the skeleton and teeth (osteomalacia/odontomalacia). It is not yet altogether clear whether these manifestations are caused solely by insufficient circulating phosphate availability for mineralization or also by a direct, local intrinsic effect caused by impaired PHEX activity. Here, we evaluated the local role of PHEX in a 3-dimensional model of extracellular matrix (ECM) mineralization. Dense collagen hydrogels were seeded either with human dental pulp cells from patients with characterized PHEX mutations or with sex- and age-matched healthy controls and cultured up to 24 d using osteogenic medium with standard phosphate concentration. Calcium quantification, micro-computed tomography, and histology with von Kossa staining for mineral showed significantly lower mineralization in XLH cell-seeded scaffolds, using nonparametric statistical tests. While apatitic mineralization was observed along collagen fibrils by electron microscopy in both groups, Raman microspectrometry indicated that XLH cells harboring the PHEX mutation produced less mineralized scaffolds having impaired mineral quality with less carbonate substitution and lower crystallinity. In the XLH cultures, immunoblotting revealed more abundant osteopontin (OPN), dentin matrix protein 1 (DMP1), and matrix extracellular phosphoglycoprotein (MEPE) than controls, as well as the presence of fragments of these proteins not found in controls, suggesting a role for PHEX in SIBLING protein degradation. Immunohistochemistry revealed altered OPN and DMP1 associated with an increased alkaline phosphatase staining in the XLH cultures. These results are consistent with impaired PHEX activity having local ECM effects in XLH. Future treatments for XLH should target both systemic and local manifestations.
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Affiliation(s)
- B R Coyac
- 1 EA 2496 Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School University Paris Descartes Sorbonne Paris Cité, and Life imaging Platform (PIV), Montrouge, France.,2 Department of Periodontology, U.F.R. of Odontology, Rothschild Hospital, AP-HP, Paris Diderot University, Paris, France.,3 Faculty of Dentistry, Division of Biomedical Sciences, McGill University, Montreal, QC, Canada
| | - B Hoac
- 3 Faculty of Dentistry, Division of Biomedical Sciences, McGill University, Montreal, QC, Canada
| | - P Chafey
- 4 INSERM U1016, Institut Cochin and Proteomic core facility of University Paris Descartes (3P5) Sorbonne Paris Cité, Paris, France
| | - G Falgayrac
- 5 Lille University, University of Littoral Côte d'Opale, EA 4490-PMOI-Pathophysiology of Inflammatory Bone Diseases, Lille, France
| | - L Slimani
- 1 EA 2496 Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School University Paris Descartes Sorbonne Paris Cité, and Life imaging Platform (PIV), Montrouge, France
| | - P S Rowe
- 6 The Kidney Institute, University of Kansas Medical Center, Kansas City, KS, USA
| | - G Penel
- 5 Lille University, University of Littoral Côte d'Opale, EA 4490-PMOI-Pathophysiology of Inflammatory Bone Diseases, Lille, France
| | - A Linglart
- 7 APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Plateforme of Expertise Paris Sud for Rare Disesdes, filière OSCAR, Bicêtre Hospital, Le Kremlin-Bicêtre, France.,8 INSERM U1169, University Paris Sud Paris-Saclay, Paris, France
| | - M D McKee
- 3 Faculty of Dentistry, Division of Biomedical Sciences, McGill University, Montreal, QC, Canada.,9 Faculty of Medicine, Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - C Chaussain
- 1 EA 2496 Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School University Paris Descartes Sorbonne Paris Cité, and Life imaging Platform (PIV), Montrouge, France.,7 APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Plateforme of Expertise Paris Sud for Rare Disesdes, filière OSCAR, Bicêtre Hospital, Le Kremlin-Bicêtre, France.,10 Department of Odontology, Bretonneau Hospital PNVS, AP-HP, Paris, France
| | - C Bardet
- 1 EA 2496 Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School University Paris Descartes Sorbonne Paris Cité, and Life imaging Platform (PIV), Montrouge, France
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