Nobuaki Ito1, Takuo Kubota2, Sachiko Kitanaka3, Ikuma Fujiwara4, Masanori Adachi5, Yasuhiro Takeuchi6,7, Hitomi Yamagami8, Takehide Kimura8, Tatsuya Shinoda8, Masanori Minagawa9, Ryo Okazaki10, Keiichi Ozono2, Yoshiki Seino11, Seiji Fukumoto12. 1. Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. nobitotky@gmail.com. 2. Department of Pediatrics, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan. 3. Department of Pediatrics, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. 4. Department of Pediatric Endocrinology and Environmental Medicine, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan. 5. Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, Kanagawa, 232-8555, Japan. 6. Endocrine Center, Toranomon Hospital, 2-2-2, Toranomon, Minato-ku, Tokyo, 105-8470, Japan. 7. Okinaka Memorial Institute for Medical Research, Toranomon, Minato-ku, Tokyo, 105-8470, Japan. 8. Minaris Medical Co., Ltd., 1-8-10 Harumi, Chuo-ku, Tokyo, 104-6004, Japan. 9. Division of Endocrinology, Chiba Children's Hospital, 579-1 Hetacho, Midoriku, Chiba, 266-0007, Japan. 10. Division of Endocrinology and Metabolism, Third Department of Medicine, Teikyo University Chiba Medical Center, Ichihara, Chiba, Japan. 11. Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan. 12. Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
Abstract
INTRODUCTION: Measurement of fibroblast growth factor 23 (FGF23) has been reported to be clinically useful for the differential diagnosis of chronic hypophosphatemia. However, assays for research use only are available in Japan. Thus, the objective of this study was to examine the clinical utility of a novel and automated chemiluminescent enzyme immunoassay for the measurement of FGF23. MATERIALS AND METHODS: Participants were recruited from July 2015 to January 2017 at six facilities in Japan. Thirty-eight patients with X-linked hypophosphatemic rickets (XLH 15 males, 23 females, age 0-66 years), five patients with tumour-induced osteomalacia (TIO 3 males, 2 females, age 60-73 years), and twenty-two patients with hypophosphatemia (11 males, 11 females, age 1-75 years) caused due to other factors participated in this study. RESULTS: With the clinical cut-off value of FGF23 at 30.0 pg/mL indicated in the Diagnostic Guideline of Rickets/Osteomalacia in Japan, the sensitivity and specificity of FGF23-related hypophosphatemic rickets/osteomalacia without vitamin D deficiency (disease group-1) were 100% and 81.8%, respectively, which distinguished it from non-FGF23-related hypophosphatemia (disease group-2). Furthermore, the diagnostic sensitivity of FGF23-related hypophosphatemia with vitamin D deficiency remained at 100%. Among the four patients with FGF23 levels ≥ 30.0 pg/mL in disease group-2, two patients with relatively higher FGF23 values were suspected to have genuine FGF23-related hypophosphatemia, due to the ectopic production of FGF23 in pulmonary and prostate small cell carcinomas. CONCLUSION: The novel FGF23 assay tested in this study is useful for the differential diagnosis of hypophosphatemic rickets/osteomalacia in a clinical setting.
INTRODUCTION: Measurement of fibroblast growth factor 23 (FGF23) has been reported to be clinically useful for the differential diagnosis of chronic hypophosphatemia. However, assays for research use only are available in Japan. Thus, the objective of this study was to examine the clinical utility of a novel and automated chemiluminescent enzyme immunoassay for the measurement of FGF23. MATERIALS AND METHODS:Participants were recruited from July 2015 to January 2017 at six facilities in Japan. Thirty-eight patients with X-linked hypophosphatemic rickets (XLH 15 males, 23 females, age 0-66 years), five patients with tumour-induced osteomalacia (TIO 3 males, 2 females, age 60-73 years), and twenty-two patients with hypophosphatemia (11 males, 11 females, age 1-75 years) caused due to other factors participated in this study. RESULTS: With the clinical cut-off value of FGF23 at 30.0 pg/mL indicated in the Diagnostic Guideline of Rickets/Osteomalacia in Japan, the sensitivity and specificity of FGF23-related hypophosphatemic rickets/osteomalacia without vitamin Ddeficiency (disease group-1) were 100% and 81.8%, respectively, which distinguished it from non-FGF23-related hypophosphatemia (disease group-2). Furthermore, the diagnostic sensitivity of FGF23-related hypophosphatemia with vitamin Ddeficiency remained at 100%. Among the four patients with FGF23 levels ≥ 30.0 pg/mL in disease group-2, two patients with relatively higher FGF23 values were suspected to have genuine FGF23-related hypophosphatemia, due to the ectopic production of FGF23 in pulmonary and prostate small cell carcinomas. CONCLUSION: The novel FGF23 assay tested in this study is useful for the differential diagnosis of hypophosphatemic rickets/osteomalacia in a clinical setting.
Authors: Thomas O Carpenter; Michael P Whyte; Erik A Imel; Annemieke M Boot; Wolfgang Högler; Agnès Linglart; Raja Padidela; William Van't Hoff; Meng Mao; Chao-Yin Chen; Alison Skrinar; Emil Kakkis; Javier San Martin; Anthony A Portale Journal: N Engl J Med Date: 2018-05-24 Impact factor: 91.245
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Authors: Andrea Trombetti; Nasser Al-Daghri; Maria Luisa Brandi; Jorge B Cannata-Andía; Etienne Cavalier; Manju Chandran; Catherine Chaussain; Lucia Cipullo; Cyrus Cooper; Dieter Haffner; Pol Harvengt; Nicholas C Harvey; Muhammad Kassim Javaid; Famida Jiwa; John A Kanis; Andrea Laslop; Michaël R Laurent; Agnès Linglart; Andréa Marques; Gabriel T Mindler; Salvatore Minisola; María Concepción Prieto Yerro; Mario Miguel Rosa; Lothar Seefried; Mila Vlaskovska; María Belén Zanchetta; René Rizzoli Journal: Nat Rev Endocrinol Date: 2022-04-28 Impact factor: 43.330