The Difficult Diagnosis of Hypophosphatemic Rickets-A Review of 8 Clinical Cases
Clinical Medicine Research
Volume 9, Issue 5, September 2020, Pages: 97-102
Received: Aug. 3, 2020;
Accepted: Aug. 18, 2020;
Published: Sep. 14, 2020
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Anna-Maria Borissova, Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria; Medical Faculty, Sofia University “Saint Kliment Ohridsky”, Sofia, Bulgaria
Yordan Vlahov, Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria; Medical Faculty, Sofia University “Saint Kliment Ohridsky”, Sofia, Bulgaria
Seiji Fukumoto, Department of Molecular Endocrinology, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
Yuichiro Shimizu, Shimizu Clinic Akasaka, Minato-ku, Tokyo, Japan
Todor Zahariev, Clinic of Vascular and Endovascular Surgery, University Hospital “Saint Ekaterina”, Sofia, Bulgaria; Medical Faculty, Medical University, Sofia, Bulgaria
Valentin Govedarski, Clinic of Vascular and Endovascular Surgery, University Hospital “Saint Ekaterina”, Sofia, Bulgaria; Medical Faculty, Medical University, Sofia, Bulgaria
Svetoslav Dimitrov, Clinic of Vascular and Endovascular Surgery, University Hospital “Saint Ekaterina”, Sofia, Bulgaria; Medical Faculty, Medical University, Sofia, Bulgaria
Radina Ivanova, Medical Faculty, Medical University, Sofia, Bulgaria; Pathological Department, University Hospital Alexandrovsa, Sofia, Bulgaria
Milena Nikolova, Medical Faculty, Medical University, Sofia, Bulgaria; Clinic of Nephrology, University Hospital “Saint Ivan Rilski”, Sofia, Bulgaria
Boyana Trifonova, Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria; Medical Faculty, Sofia University “Saint Kliment Ohridsky”, Sofia, Bulgaria
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Hypophosphatemic rickets is a rare, usually genetic disease associated with decreased phosphate reabsorption in the proximal renal tubule and vitamin D resistance. Several genetic mutations have been discovered, the most common being the X-linked PHEX mutation with high fibroblast growth factor 23 (FGF23) circulating levels. The hypophosphatemic type osteomalacia is usually hereditary or tumour-induced (TIO). In the past 20 years, we have discovered, treated and followed up overall 8 cases of the disease-3 women and 5 men, aged 18 to 52 years. In all patients the diagnostic process was long (a mean of 2-3 years) and involved multiple clinical consults, laboratory evaluations: Biochemical Standard Research, Hormonal Tests [PTH, 25 (OH) D, 1,25 (OH) 2D], Specialized Research (FGF23), Instrumental Research (Ultrasonography of whole body; Computed tomography; Magnetic resonance imaging; DXA examination with an assessment of T-score and Z-score of spine/hip). All of these studies aimed at ruling out different neurological, hematological, oncological, rheumatic, gastroenterological, urological, nephrological diseases and conditions. One of the patients had Fanconi syndrome, five had X-linked hypophosphatemia (XLH) and two had TIO. In the last two patients, we found a high level of FGF23 secreting a small lung neoplasm in the first case and a mesenchymal tumor in the median upper part of the right thigh in the second case. The surgical removal of the tumor mass lead to a fast decrease in FGF23 levels and correction of metabolic disturbances. We present clinical cases with hypophosphatemic rickets/osteomalacia and discuss the etiopathogenesis and treatment of this rare disease. Historically until now phosphate supplementation and therapy using analogs of highly active vitamin D (calcitriol, alfacalcidol, paricalcitol) have been used to manage conditions involving hypophosphatemia. In recent years there has been a progression of clinical trials for monoclonal anti-FGF23 antibodies for the treatment of XLH. These monoclonal anti-FGF23 antibodies may have potential for treating other conditions associated with FGF23 overactivity. However, clinical trials to support that possibility are not available at present.
Hypophosphatemic Rickets, FGF23, Hereditary Forms, Mesenchymal Tumour, Treatment
To cite this article
The Difficult Diagnosis of Hypophosphatemic Rickets-A Review of 8 Clinical Cases, Clinical Medicine Research.
Vol. 9, No. 5,
2020, pp. 97-102.
Copyright © 2020 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/
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