{ "schemaVersion": 2, "eyebrow": "Metabolic Bone Disease", "title": "Osteomalacia", "summary": "Evaluate suspected osteomalacia by separating vitamin D or calcium deficiency from renal phosphate wasting. A low phosphate value requires assessment of renal phosphate handling, vitamin D metabolites, alkaline phosphatase, parathyroid hormone, and targeted evaluation for FGF23-mediated disease or acquired malabsorption.", "seoDescription": "Point-of-care evaluation of osteomalacia: distinguish vitamin D deficiency, calcium deficiency, renal phosphate wasting, FGF23 excess, and tumor-induced osteomalacia.", "clinicalQuestion": "How should clinicians identify the biochemical cause of osteomalacia and direct cause-specific evaluation?", "specialty": "Endocrinology", "audience": "U.S. physicians and medical trainees", "tags": [ "osteomalacia", "hypophosphatemia", "renal phosphate wasting", "FGF23", "tumor-induced osteomalacia", "vitamin D deficiency", "TmP/GFR" ], "keyTakeaways": [ "Do not attribute osteomalacia to vitamin D deficiency without measuring 25-hydroxyvitamin D, phosphate, calcium, alkaline phosphatase, parathyroid hormone, creatinine, and renal phosphate handling. [6][22]", "In hypophosphatemia, a reduced TmP/GFR establishes inappropriate renal phosphate loss and redirects evaluation toward FGF23-mediated and proximal tubular disorders. [6][21]", "Low or inappropriately normal 1,25-dihydroxyvitamin D with hypophosphatemia and renal phosphate wasting supports an FGF23-mediated process; measure FGF23 before treatment when possible. [6][7]", "Adult-onset FGF23-mediated osteomalacia without a lifelong skeletal phenotype should prompt evaluation for tumor-induced osteomalacia, a potentially curable paraneoplastic cause of renal phosphate wasting. [1][7][8]", "For FGF23-mediated disorders, conventional oral phosphate plus active vitamin D can cause gastrointestinal intolerance and renal toxicity; burosumab is an approved targeted therapy for X-linked hypophosphatemia and tumor-induced osteomalacia. [9][14][16]" ], "sections": [ { "id": "initial-biochemical-branching", "eyebrow": "Diagnostic Entry Point", "heading": "Order a mineralization-focused panel before assigning a cause", "intro": "Use biochemical pattern recognition to decide whether the dominant defect is vitamin D/calcium related or phosphate related.", "paragraphs": [ "In adults with bone pain, proximal weakness, insufficiency fractures, or suspected impaired mineralization, obtain serum phosphate, calcium, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and creatinine. Obtain spot urine phosphate, creatinine, and calcium concurrently to calculate tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR) and urinary calcium:creatinine ratio. [6]", "An elevated alkaline phosphatase supports active rickets or osteomalacia but is not etiologic. In adults, use bone-specific alkaline phosphatase when available because approximately half of circulating total alkaline phosphatase originates from hepatocytes. Persistently elevated alkaline phosphatase with low urinary calcium is described in undertreated hypophosphatemic rickets or osteomalacia; alkaline phosphatase usually falls and urinary calcium rises with skeletal healing. [6]", "Very low 25-hydroxyvitamin D favors nutritional vitamin D deficiency as a mineralization defect. Osteomalacia related to vitamin D deficiency is typically associated with 25-hydroxyvitamin D concentrations below 15 to 30 nmol/L; vitamin D deficiency can cause osteomalacia, muscle weakness, and worsen osteopenia or osteoporosis. [2][22]" ], "bullets": [ "Draw serum phosphate before initiating phosphate replacement when feasible; treatment can obscure the renal phosphate-wasting pattern. [6]", "Interpret alkaline phosphatase with hepatic tests or bone-specific measurement in adults when liver disease is plausible. [6]", "A normal serum calcium does not exclude deficient body calcium stores or nutritional osteomalacia. [11]" ], "subsections": [], "table": { "caption": "Biochemical patterns that direct the next etiologic step in osteomalacia. [6][7][21][22]", "columns": [ "Pattern", "Discriminating findings", "Next action" ], "rows": [ [ "Vitamin D-related osteomalacia", "Very low 25-hydroxyvitamin D; calcium may not reflect total body calcium stores. [11][22]", "Identify deficient intake, malabsorption, or other causes of vitamin D depletion; use the biochemical response to repletion to confirm correction of the mineralization defect. [2][22]" ], [ "Renal phosphate wasting", "Hypophosphatemia with reduced TmP/GFR. [6][21]", "Determine whether phosphate loss is isolated or accompanied by other tubular losses; then assess the FGF23/1,25-dihydroxyvitamin D pattern. [21]" ], [ "FGF23-mediated phosphate wasting", "Reduced TmP/GFR with low or low-normal 1,25-dihydroxyvitamin D; FGF23 is inappropriately elevated in the hypophosphatemic state. [6][7]", "Differentiate inherited hypophosphatemic rickets from tumor-induced osteomalacia using age at onset, family history, dental and skeletal phenotype, and tumor-directed evaluation when acquired. [6][7][8]" ], [ "Non-FGF23 proximal tubular disorder", "Renal phosphate wasting accompanied by additional tubular losses. [21]", "Evaluate the associated proximal tubular abnormalities rather than labeling the disorder as isolated FGF23-mediated osteomalacia. [21]" ] ] } }, { "id": "confirm-renal-phosphate-wasting", "eyebrow": "Hypophosphatemia", "heading": "Use TmP/GFR to distinguish renal loss from nonrenal phosphate depletion", "intro": "A low serum phosphate alone does not establish the mechanism of osteomalacia.", "paragraphs": [ "Calculate TmP/GFR from paired serum and spot urine phosphate and creatinine in patients with hypophosphatemia. A low TmP/GFR documents impaired tubular phosphate reabsorption and establishes renal phosphate wasting; this is the pivotal branch point before pursuing FGF23-mediated disorders, inherited phosphate-wasting conditions, or generalized proximal tubular dysfunction. [6][21]", "After renal phosphate wasting is documented, determine whether loss is isolated or occurs with other tubular solute losses. Isolated phosphate wasting is compatible with FGF23-mediated disease, whereas associated tubular losses redirect the evaluation to proximal tubular disorders. [21]", "Measure 1,25-dihydroxyvitamin D and FGF23 in the untreated state when possible. FGF23 physiologically increases renal phosphate wasting and suppresses active vitamin D; therefore, hypophosphatemia with low-normal 1,25-dihydroxyvitamin D is a characteristic FGF23-excess pattern. FGF23 measurements are most informative before therapy, and assay-specific reference ranges vary substantially. [6][7]" ], "bullets": [ "Do not interpret a low 1,25-dihydroxyvitamin D result in isolation; its diagnostic value is strongest when paired with hypophosphatemia and reduced TmP/GFR. [6][7]", "A low 25-hydroxyvitamin D level does not rule out hypophosphatemic rickets or osteomalacia. [21]", "Use the laboratory-specific FGF23 assay and reference interval; a result must be interpreted relative to the concurrent hypophosphatemia. [6]" ], "subsections": [], "table": { "caption": "Clinical discriminators after renal phosphate wasting is established. [6][7][18][21]", "columns": [ "Feature", "Inherited FGF23-mediated disease", "Tumor-induced osteomalacia", "HHRH or other non-FGF23 renal phosphate wasting" ], "rows": [ [ "Typical timing", "Childhood or longstanding disease, often with family history. [18]", "Acquired adult presentation is typical. [1][7][8]", "May present with rickets or osteomalacia; nephrolithiasis has been reported in adulthood with HHRH. [21]" ], [ "Renal phosphate handling", "Reduced TmP/GFR. [18]", "Reduced TmP/GFR. [6][7]", "Reduced TmP/GFR. [21]" ], [ "FGF23 and active vitamin D pattern", "FGF23 elevation with low-to-normal 1,25-dihydroxyvitamin D. [18]", "Hypophosphatemia with low-normal 1,25-dihydroxyvitamin D and tumor-associated FGF23 excess. [7][8]", "Genetically distinct renal phosphate wasting; assess urinary calcium and clinical features rather than assuming FGF23 excess. [21]" ], [ "Clinical clues", "Rickets, growth impairment, lower-limb deformity, dental abnormalities, and possible craniosynostosis or intracranial hypertension. [4][6]", "Progressive bone pain, weakness, fatigue, fragility fractures, height loss, and delayed diagnosis are characteristic. [7]", "Bone pain, weakness, pseudofractures, and absence of dental abnormalities are described in HHRH. [21]" ] ] } }, { "id": "fgf23-mediated-osteomalacia", "eyebrow": "Etiologic Branch", "heading": "Differentiate inherited hypophosphatemia from tumor-induced osteomalacia", "intro": "Age at onset and phenotype determine whether to seek a hereditary disorder or an occult phosphaturic tumor.", "paragraphs": [ "A lifelong history of rickets, short stature or growth failure, lower-limb deformity, dental abnormalities, or a family history supports inherited hypophosphatemic disease. The recommended clinical evaluation for X-linked hypophosphatemia includes assessment for rickets, growth failure, dental abnormalities, and craniosynostosis or intracranial hypertension, with radiologic grading of rickets or osteomalacic lesions and biochemical measurement of phosphate handling. [4][6]", "Consider tumor-induced osteomalacia in an adult with acquired progressive bone pain, muscle weakness, fatigue, insufficiency or fragility fractures, hypophosphatemia, low TmP/GFR, elevated alkaline phosphatase, and low-normal 1,25-dihydroxyvitamin D. Tumor-induced osteomalacia is a rare paraneoplastic form of renal phosphate wasting caused by FGF23-secreting tumors, which are often small and may produce years of diagnostic delay. [1][7][8]", "The key clinical consequence of recognizing tumor-induced osteomalacia is potential cure: complete excision of the responsible tumor is associated with dramatic symptomatic improvement and correction of metabolic abnormalities. Once the biochemical phenotype supports acquired FGF23 excess, shift the workup from empiric supplementation alone to localization and definitive tumor-directed treatment. [7]" ], "bullets": [ "Do not use absence of a visible mass to exclude tumor-induced osteomalacia; the responsible tumors are typically small. [7]", "Document baseline bone pain, weakness, fracture burden, alkaline phosphatase, serum phosphate, and TmP/GFR before definitive treatment to assess biochemical and clinical resolution. [6][7]", "If the phenotype is acquired but no tumor is identified, maintain management of FGF23-mediated phosphate wasting while continuing tumor-directed evaluation. [8][10]" ], "subsections": [], "table": null }, { "id": "treatment-principles", "eyebrow": "Management", "heading": "Treat the cause and monitor biochemical healing", "intro": "Treatment differs materially between nutritional osteomalacia, inherited FGF23 excess, and tumor-induced osteomalacia.", "paragraphs": [ "For nutritional osteomalacia, correct the documented vitamin D and calcium deficit and address the source of deficiency, including malabsorption when present. Nutritional osteomalacia may respond to low doses of calcium and vitamin D, whereas vitamin D deficiency rickets is described as responsive to small vitamin D doses; regimen selection and monitoring should be individualized because the cited literature does not provide a universal adult dosing protocol. [22]", "For FGF23-mediated hypophosphatemia, conventional management has used oral phosphate with active vitamin D analogs. This approach may be limited by gastrointestinal intolerance and renal toxicity, can increase FGF23 concentrations, and often does not normalize serum phosphate, leaving persistent skeletal risk. [9]", "Burosumab is a monoclonal antibody against FGF23 and is approved for X-linked hypophosphatemia and tumor-induced osteomalacia. It provides a targeted option when these diagnoses are established, including tumor-induced osteomalacia in which a tumor cannot be identified or cannot be definitively treated; its use should be paired with serial biochemical and skeletal assessment. [14][16][17]" ], "bullets": [ "Use alkaline phosphatase as a treatment-response biomarker for active rickets or osteomalacia; declining values support healing, but interpret total alkaline phosphatase cautiously in adults with possible hepatobiliary contribution. [6]", "Monitor serum phosphate and renal phosphate handling during management of phosphate-wasting osteomalacia, because symptom improvement alone does not establish correction of the underlying renal leak. [6][7]", "After complete resection of a tumor-induced osteomalacia lesion, confirm correction with serum phosphate and the previously abnormal metabolic markers rather than assuming cure from surgery alone. [7]" ], "subsections": [], "table": { "caption": "Cause-directed management priorities in osteomalacia. [6][7][9][14][16][22]", "columns": [ "Etiology", "Definitive priority", "Monitoring target or limitation" ], "rows": [ [ "Nutritional vitamin D/calcium deficiency", "Replace documented vitamin D and calcium deficits and identify the driver of depletion or malabsorption. [22]", "Follow biochemical correction and alkaline phosphatase activity; normal calcium alone is not an adequate marker of calcium stores. [6][11]" ], [ "Inherited FGF23-mediated hypophosphatemia", "Use disease-specific management; burosumab is approved for X-linked hypophosphatemia. [14][16]", "Monitor phosphate, renal phosphate handling, alkaline phosphatase, and skeletal manifestations. [6]" ], [ "Tumor-induced osteomalacia with localized lesion", "Pursue complete tumor excision, which can correct metabolic abnormalities and symptoms. [7]", "Confirm postoperative normalization of phosphate-related abnormalities and clinical recovery. [7]" ], [ "Tumor-induced osteomalacia without identifiable or treatable tumor", "Manage FGF23-mediated hypophosphatemia; burosumab is approved for tumor-induced osteomalacia. [14][16]", "Conventional phosphate plus active vitamin D has gastrointestinal and renal toxicity limitations and may not normalize serum phosphate. [9]" ] ] } }, { "id": "imaging-and-escalation", "eyebrow": "Escalation", "heading": "Escalate acquired renal phosphate wasting to tumor-directed evaluation", "intro": "The combination of adult onset and FGF23-mediated renal phosphate wasting should not be managed as nutritional deficiency alone.", "paragraphs": [ "Obtain radiologic evaluation to identify and grade osteomalacic lesions when the diagnosis is suspected or disease activity must be established. In an adult with biochemical FGF23-mediated phosphate wasting and no childhood phenotype, use the imaging strategy to support localization of an occult phosphaturic tumor rather than to merely document fractures. [6][7][8]", "Refer patients with suspected tumor-induced osteomalacia for coordinated endocrine, metabolic bone, and tumor-localization evaluation because complete lesion excision is the intervention linked to correction of the syndrome. Thermal ablation has been reported as a treatment approach for tumor-induced osteomalacia, but complete excision remains the documented curative mechanism in the cited clinical literature. [7][15]", "Escalate promptly when progressive weakness, multiple fragility fractures, height loss, or persistent biochemical phosphate wasting is present. These findings are described in delayed tumor-induced osteomalacia and signal ongoing mineralization failure rather than uncomplicated low bone density. [7]" ], "bullets": [ "Use the adult-versus-childhood onset distinction as a localization trigger: acquired FGF23-mediated osteomalacia warrants focused consideration of tumor-induced osteomalacia. [1][7][8]", "Do not substitute osteoporosis terminology for a phosphate-wasting evaluation when alkaline phosphatase is elevated and hypophosphatemia is persistent. [6][7]", "If treatment has already begun, interpret FGF23 cautiously because measurement is most informative in untreated patients. [6]" ], "subsections": [], "table": null } ], "faq": [ { "question": "Can a normal serum calcium exclude nutritional osteomalacia?", "answer": "No. Serum calcium is a poor marker of total body calcium status; assess 25-hydroxyvitamin D, parathyroid hormone, alkaline phosphatase, phosphate, and the clinical context rather than using calcium alone. [11][22]" }, { "question": "When should tumor-induced osteomalacia be suspected?", "answer": "Suspect it in acquired adult hypophosphatemic osteomalacia with reduced TmP/GFR, low-normal 1,25-dihydroxyvitamin D, and an FGF23-excess phenotype, especially with progressive bone pain, weakness, fractures, or height loss. 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Verify recommendations against current guidance and patient-specific factors.", "citations": [ { "number": 1, "title": "Tumor-Induced Osteomalacia | Geriatrics - JAMA Network", "detail": "jamanetwork.com", "url": "https://jamanetwork.com/journals/jama/article-abstract/201505", "authors": "jamanetwork.com", "host": "jamanetwork.com", "snippet": "Tumor-induced osteomalacia (TIO) is a rare paraneoplastic form of renal phosphate wasting that results in severe hypophosphatemia, a defect in vitamin D.", "score": 0.6407488 }, { "number": 2, "title": "Vitamin D Deficiency | New England Journal of Medicine", "detail": "www.nejm.org", "url": "https://www.nejm.org/doi/full/10.1056/NEJMra070553", "authors": "www.nejm.org", "host": "www.nejm.org", "snippet": "Vitamin D deficiency in adults can precipitate or exacerbate osteopenia and osteoporosis, cause osteomalacia and muscle weakness, and increase", "score": 0.47811517 }, { "number": 3, "title": "Vitamin D Metabolism in Hypophosphatemic Rickets | JAMA Pediatrics", "detail": "jamanetwork.com", "url": "https://jamanetwork.com/journals/jamapediatrics/fullarticle/510660", "authors": "jamanetwork.com", "host": "jamanetwork.com", "snippet": "The reduction of serum 1,25-(OH)2D levels with ergocalciferol and phosphate therapy ... hypophosphatemic osteomalacia: Treatment with 1α-hydroxyvitamin D3 . Clin", "score": 0.42076674 }, { "number": 4, "title": "Burosumab Therapy in Children with X-Linked Hypophosphatemia", "detail": "www.nejm.org", "url": "https://www.nejm.org/doi/full/10.1056/NEJMoa1714641", "authors": "www.nejm.org", "host": "www.nejm.org", "snippet": "Chronic hypophosphatemia leads to rickets and osteomalacia, which often result in stunted growth, lower-limb deformity, pain, and physical", "score": 0.32405406 }, { "number": 5, "title": "Fibroblast Growth Factor 23 in Oncogenic Osteomalacia and X ...", "detail": "www.nejm.org", "url": "https://www.nejm.org/doi/full/10.1056/NEJMoa020881", "authors": "www.nejm.org", "host": "www.nejm.org", "snippet": "Clinical and laboratory findings in this disorder are similar to those in oncogenic osteomalacia, in which tumors abundantly express FGF-23 messenger RNA, and", "score": 0.18559302 }, { "number": 6, "title": "Clinical practice recommendations for the diagnosis and ... - Nature", "detail": "www.nature.com", "url": "https://www.nature.com/articles/s41581-019-0152-5", "authors": "www.nature.com", "host": "www.nature.com", "snippet": "A detailed clinical evaluation, including evidence of rickets, growth failure, dental abnormalities and signs of craniosynostosis and/or intracranial hypertension\n\nA radiological evaluation to diagnose and grade rickets and osteomalacic lesions\n\nBiochemical tests, including serum levels of phosphate", "score": 0.6757865 }, { "number": 7, "title": "FGF23 and Phosphate Wasting Disorders | Bone Research", "detail": "www.nature.com", "url": "https://www.nature.com/articles/boneres20139", "authors": "www.nature.com", "host": "www.nature.com", "snippet": "FGF23 is almost exclusively produced by osteocytes and osteoblasts in response to high serum phosphate levels and 1,25(OH)2D (17,24. 2009;58:381–392.\")), although aberrant production may occur in mesenchymal tumors associated with hypophosphatemic osteomalacia (25) and in the tissue of fibrous dyspl", "score": 0.60358196 }, { "number": 8, "title": "Tumour-induced osteomalacia | Nature Reviews Disease Primers", "detail": "www.nature.com", "url": "https://www.nature.com/articles/nrdp201744", "authors": "www.nature.com", "host": "www.nature.com", "snippet": "Tumour-induced osteomalacia (TIO), also known as oncogenic osteomalacia, is a rare paraneoplastic disorder caused by tumours that secrete", "score": 0.18055448 }, { "number": 9, "title": "A phase 2 trial of burosumab for treatment of fibroblast growth factor-23-mediated hypophosphatemia in children and adults with fibrous dysplasia | Bone Research", "detail": "www.nature.com", "url": "https://www.nature.com/articles/s41413-026-00523-7", "authors": "www.nature.com", "host": "www.nature.com", "snippet": "use of burosumab in the FGF23 excess disorders X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), leading to improved serum phosphate levels and skeletal outcomes without adverse gastrointestinal or renal side effects.11.\"),12.\"),13.\"),14.\"),15.\"),16.\") [...] Article \nGoogle Schol", "score": 0.51691306 }, { "number": 10, "title": "Burosumab in Unidentifiable Tumor‐Induced Osteomalacia", "detail": "onlinelibrary.wiley.com", "url": "https://onlinelibrary.wiley.com/doi/pdf/10.1002/ccr3.71600", "authors": "onlinelibrary.wiley.com", "host": "onlinelibrary.wiley.com", "snippet": "Initial laboratory results (Table 1) revealed low serum phosphate and TmP- GFR, high ALP, near- normal 25- hydroxyvitamin D, low 1, 25- dihydroxyvitamin D, and", "score": 0.66203266 }, { "number": 11, "title": "Nutritional rickets & osteomalacia", "detail": "journals.lww.com", "url": "https://journals.lww.com/ijmr/fulltext/2020/52040/nutritional_rickets___osteomalacia__a_practical.6.aspx", "authors": "journals.lww.com", "host": "journals.lww.com", "snippet": "While 25OHD is a good marker or vitamin D status, serum calcium is a very poor marker of calcium status in the body. The calcium stores in the body, mainly the", "score": 0.5299209 }, { "number": 12, "title": "Phosphate, Fractures, and Frustration—A Missed Diagnosis of ...", "detail": "onlinelibrary.wiley.com", "url": "https://onlinelibrary.wiley.com/doi/full/10.1002/ccr3.70790", "authors": "onlinelibrary.wiley.com", "host": "onlinelibrary.wiley.com", "snippet": "renal phosphate wasting due to excess 23 (FGF23) This results in hypophosphatemia, osteomalacia, muscular weakness, and bone pain. FGF23 levels", "score": 0.474023 }, { "number": 13, "title": "induced osteomalacia - Wiley Online Library", "detail": "onlinelibrary.wiley.com", "url": "https://onlinelibrary.wiley.com/doi/pdf/10.1111%2Fjoim.13593", "authors": "onlinelibrary.wiley.com", "host": "onlinelibrary.wiley.com", "snippet": "Tumor-induced osteomalacia (TIO) is a rare para- neoplastic syndrome, resulting from the secretion of the phosphaturic hormone fibroblast growth factor 23 (", "score": 0.34112197 }, { "number": 14, "title": "Burosumab, a Transformational Treatment in a Pediatric Patient With ...", "detail": "academic.oup.com", "url": "https://academic.oup.com/jcemcr/article/2/10/luae184/7823785", "authors": "academic.oup.com", "host": "academic.oup.com", "snippet": "Burosumab is approved to treat patients with X-linked hypophosphatemia and tumor-induced osteomalacia [4][5]. Safety and efficacy were reported", "score": 0.6010557 }, { "number": 15, "title": "Thermal Ablation for Treating Tumor-induced Osteomalacia in a ...", "detail": "academic.oup.com", "url": "https://academic.oup.com/jcemcr/article/1/4/luad086/7232442", "authors": "academic.oup.com", "host": "academic.oup.com", "snippet": "TIO is a rare phosphate-wasting disorder caused by increased ... Long-term use of burosumab for the treatment of tumor-induced osteomalacia.", "score": 0.5654673 }, { "number": 16, "title": "Burosumab use in fibroblast growth factor-23-mediated ...", "detail": "academic.oup.com", "url": "https://academic.oup.com/jcemcr/article/4/6/luag086/8670639", "authors": "academic.oup.com", "host": "academic.oup.com", "snippet": "Burosumab, a monoclonal antibody against FGF-23, is approved for X-linked hypophosphatemia and tumor-induced osteomalacia and has shown promise in case reports", "score": 0.5565207 }, { "number": 17, "title": "Burosumab treatment for fibroblast growth factor-23-associated ...", "detail": "academic.oup.com", "url": "https://academic.oup.com/jbmrplus/article/9/9/ziaf125/8212267", "authors": "academic.oup.com", "host": "academic.oup.com", "snippet": "Burosumab, a monoclonal antibody against FGF23, is approved for the treatment X-linked hypophosphatemia and tumor-induced osteomalacia.", "score": 0.5393963 }, { "number": 18, "title": "Familial Hypophosphatemic Rickets - an overview | ScienceDirect Topics", "detail": "www.sciencedirect.com", "url": "https://www.sciencedirect.com/topics/medicine-and-dentistry/familial-hypophosphatemic-rickets", "authors": "www.sciencedirect.com", "host": "www.sciencedirect.com", "snippet": "Title: Familial Hypophosphatemic Rickets - an overview | ScienceDirect Topics\n**Vitamin D–resistant rickets** (VDRR), also known as *familial hypophosphatemic rickets*, represents a group of heritable conditions that are characterized by loss of phosphate in the urine (leading to reduced serum phosp", "score": 0.6437107 }, { "number": 19, "title": "Evaluation of Hypophosphatemia: Lessons From Patients With Genetic Disorders - ScienceDirect", "detail": "www.sciencedirect.com", "url": "https://www.sciencedirect.com/science/article/abs/pii/S0272638611014363", "authors": "www.sciencedirect.com", "host": "www.sciencedirect.com", "snippet": "Four groups can be distinguished: diseases with a primary excess in intact FGF23 levels (e.g., genetic X-linked hypophosphatemia and non-genetic tumor-induced osteomalacia); diseases with a primary deficiency in intact FGF23 levels or inefficient FGF23 (e.g., hyperphosphatemic tumoral calcinosis); d", "score": 0.608897 }, { "number": 20, "title": "Intact Fibroblast Growth Factor 23 Concentrations in Hypophosphatemic Disorders - ScienceDirect", "detail": "www.sciencedirect.com", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1530891X23000022", "authors": "www.sciencedirect.com", "host": "www.sciencedirect.com", "snippet": "### Calcif Tissue Int\n\n### Autosomal dominant hypophosphataemic rickets is associated with mutations in FGF23\n\n### Nat Genet\n\n### Regulation and function of the FGF23/klotho endocrine pathways\n\n### Physiol Rev\n\n### Cloning and characterization of FGF23 as a causative factor of tumor-induced osteomal", "score": 0.6055431 }, { "number": 21, "title": "Hypophosphatemic rickets : Indian Journal of Endocrinology and Metabolism", "detail": "journals.lww.com", "url": "https://journals.lww.com/indjem/fulltext/2012/16020/hypophosphatemic_rickets.6.aspx", "authors": "journals.lww.com", "host": "journals.lww.com", "snippet": "Classification of rickets (ADHR: autosomal dominant hypophosphatemic rickets, ARHR: autosomal recessive hypophosphatemic rickets, ENS: epidermal nevus syndrome, FGF23: fibroblast growth factor 23, FS: Fanconi syndrome, HHRH: hypophosphatemic rickets with hypercalciuria, NPT2a: sodium phosphate cotra", "score": 0.5923135 }, { "number": 22, "title": "Rickets and Osteomalacia - Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism - Wiley Online Library", "detail": "onlinelibrary.wiley.com", "url": "https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119266594.ch89", "authors": "onlinelibrary.wiley.com", "host": "onlinelibrary.wiley.com", "snippet": "The causes of osteomalacia and rickets are similar and can be classified according to underlying mechanisms: Vitamin D deficiency or resistance; calcium deficiency independent of vitamin D; hypophosphatemic disorders; and mineralization inhibitors. Patients with rickets and osteomalacia related to v", "score": 0.5920305 }, { "number": 23, "title": "FGF23 and disorders of phosphate homeostasis - ScienceDirect", "detail": "www.sciencedirect.com", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1359610105000031", "authors": "www.sciencedirect.com", "host": "www.sciencedirect.com", "snippet": "### Biochem Biophys Res Commun\n\n### Fibrous dysplasia of bone with Vitamin D resistant rickets: a case study\n\n### Metabolism\n\n### Circulating concentration of FGF-23 increases as renal function declines in patients with chronic kidney disease, but does not change in response to variation in phosphat", "score": 0.5602773 }, { "number": 24, "title": "PHEX gene and hypophosphatemia - Kidney International", "detail": "www.kidney-international.org", "url": "https://www.kidney-international.org/article/S0085-2538%2815%2946700-6/fulltext", "authors": "www.kidney-international.org", "host": "www.kidney-international.org", "snippet": "X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO) are diseases that have in common abnormal proximal renal tubular function resulting in", "score": 0.47416916 } ], "publishedAt": "2026-09-16T00:29:40.094633+00:00", "updatedAt": "2026-09-16T00:29:40.094633+00:00", "readingMinutes": 6, "slug": "osteomalacia" }