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Nature Reviews. Nephrology Jul 2019X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb...
X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb deformities, pain, poor mineralization of the teeth and disproportionate short stature in children as well as hyperparathyroidism, osteomalacia, enthesopathies, osteoarthritis and pseudofractures in adults. The characteristics and severity of XLH vary between patients. Because of its rarity, the diagnosis and specific treatment of XLH are frequently delayed, which has a detrimental effect on patient outcomes. In this Evidence-Based Guideline, we recommend that the diagnosis of XLH is based on signs of rickets and/or osteomalacia in association with hypophosphataemia and renal phosphate wasting in the absence of vitamin D or calcium deficiency. Whenever possible, the diagnosis should be confirmed by molecular genetic analysis or measurement of levels of fibroblast growth factor 23 (FGF23) before treatment. Owing to the multisystemic nature of the disease, patients should be seen regularly by multidisciplinary teams organized by a metabolic bone disease expert. In this article, we summarize the current evidence and provide recommendations on features of the disease, including new treatment modalities, to improve knowledge and provide guidance for diagnosis and multidisciplinary care.
Topics: Algorithms; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Arnold-Chiari Malformation; Biomarkers; Bone Density Conservation Agents; Bone and Bones; Continuity of Patient Care; Craniosynostoses; Delphi Technique; Dental Care; Familial Hypophosphatemic Rickets; Fibroblast Growth Factor-23; Growth Hormone; Hearing Loss; Humans; Immunologic Factors; Life Style; Mutation; Orthopedic Procedures; PHEX Phosphate Regulating Neutral Endopeptidase; Phosphates; Physical Therapy Modalities; Radiography; Vitamin D
PubMed: 31068690
DOI: 10.1038/s41581-019-0152-5 -
International Journal of Molecular... Nov 2022Among bone-material qualities, mineralization is pivotal in conferring stiffness and toughness to the bone. Osteomalacia, a disease ensuing from inadequate... (Review)
Review
Among bone-material qualities, mineralization is pivotal in conferring stiffness and toughness to the bone. Osteomalacia, a disease ensuing from inadequate mineralization of the skeleton, is caused by different processes leading to decreased available mineral (calcium and/or phosphate) or enzymatic alterations. Vitamin D deficiency, which remains the major cause of altered mineralization leading to inadequate intestinal calcium and phosphate absorption, may be also associated with other conditions primarily responsible for abnormal mineralization. Given the reality of widespread vitamin D inadequacy, a full biochemical assessment of mineral metabolism is always necessary to rule out or confirm other conditions. Both too-high or too-low serum alkaline phosphatase (ALP) levels are important for diagnosis. Osteomalacic syndrome is reversible, at least in part, by specific treatment. Osteomalacia and bone mineralization themselves constitute largely unexplored fields of research. The true prevalence of the different forms of osteomalacia and the recovery after proper therapy have yet to be determined in the real world. Although non-invasive techniques to assess bone mineralization are not available in clinical practice, the systematic assessment of bone quality could help in refining the diagnosis and guiding the treatment. This review summarizes what is known of osteomalacia recent therapeutic developments and highlights the future issues of research in this field.
Topics: Humans; Calcium; Osteomalacia; Vitamin D Deficiency; Vitamin D; Phosphates
PubMed: 36499221
DOI: 10.3390/ijms232314896 -
Molecular Aspects of Medicine Oct 2020Intravenous infusions of iron have evolved from a poorly effective and dangerous intervention to a safe cornerstone in the treatment of iron deficiency. Modern iron... (Review)
Review
Intravenous infusions of iron have evolved from a poorly effective and dangerous intervention to a safe cornerstone in the treatment of iron deficiency. Modern iron formulations are composite nanoparticles composed of carbohydrate ferric oxy-hydroxides. Iron dextran, iron derisomaltose (formely known as iron isomaltoside 1000), ferric carboxymaltose, ferrumoxytol, iron sucrose and sodium ferric gluconate can be infused at different doses and allow correction of total iron deficit with single or repeated doses in 1-2 weeks depending on the specific formulation. All iron preparations are associated with a risk of severe infusion reactions. In recent prospective clinical trials, the risk of moderate to severe infusion reactions was comparable among all modern preparations affecting <1% of patients. Hence, intravenous iron therapy is reserved for iron deficiency anemia patients with intolerance or unresponsiveness of oral iron. As per European drug label, intravenous iron may also be preferred when rapid correction of the iron deficit is required. In patients with inflammation, iron-deficiency should also be suspected as anemia cause when transferrin saturation is low because serum ferritin can be spuriously normal. The main treatment target for i.v. iron is an improvement of the quality of life, for which hemoglobin is a surrogate marker. An emerging complication affecting 50-74% of patients treated with ferric carboxymaltose in prospective clinical trials is hypophosphatemia - or more accurately the 6H syndrome (hyperphosphaturic hypophosphatemia triggered by high fibroblast growth factor 23 that causes hypovitaminosis D, hypocalcemia and secondary hyperparathyroidism). These biochemical changes can cause severe and potentially irreversible clinical complications, such a bone pain, osteomalacia and fractures. Individual selection of the appropriate iron therapy and evaluation of treatment response are mandatory to safely deliver improved outcome through intravenous iron therapies.
Topics: Anemia, Iron-Deficiency; Dietary Supplements; Humans; Iron; Prospective Studies; Quality of Life
PubMed: 32444112
DOI: 10.1016/j.mam.2020.100862 -
The Journal of Clinical Endocrinology... Dec 2022Hypophosphatemic rickets typically presents in infancy or early childhood with skeletal deformities and growth plate abnormalities. The most common causes are genetic...
Hypophosphatemic rickets typically presents in infancy or early childhood with skeletal deformities and growth plate abnormalities. The most common causes are genetic (such as X-linked hypophosphatemia), and these typically will result in lifelong hypophosphatemia and osteomalacia. Knowledge of phosphate metabolism, including the effects of fibroblast growth factor 23 (FGF23) (an osteocyte produced hormone that downregulates renal phosphate reabsorption and 1,25-dihydroxyvitamin-D (1,25(OH)2D) production), is critical to determining the underlying genetic or acquired causes of hypophosphatemia and to facilitate appropriate treatment. Serum phosphorus should be measured in any child or adult with musculoskeletal complaints suggesting rickets or osteomalacia. Clinical evaluation incudes thorough history, physical examination, laboratory investigations, genetic analysis (especially in the absence of a guiding family history), and imaging to establish etiology and to monitor severity and treatment course. The treatment depends on the underlying cause, but often includes active forms of vitamin D combined with phosphate salts, or anti-FGF23 antibody treatment (burosumab) for X-linked hypophosphatemia. The purpose of this article is to explore the approach to evaluating hypophosphatemic rickets and its treatment options.
Topics: Adult; Child; Child, Preschool; Humans; Familial Hypophosphatemic Rickets; Osteomalacia; Fibroblast Growth Factors; Rickets, Hypophosphatemic; Hypophosphatemia; Phosphates
PubMed: 35981346
DOI: 10.1210/clinem/dgac488 -
Endocrine Reviews Aug 2019The etiology of endemic rickets was discovered a century ago. Vitamin D is the precursor of 25-hydroxyvitamin D and other metabolites, including 1,25(OH)2D, the ligand... (Review)
Review
The etiology of endemic rickets was discovered a century ago. Vitamin D is the precursor of 25-hydroxyvitamin D and other metabolites, including 1,25(OH)2D, the ligand for the vitamin D receptor (VDR). The effects of the vitamin D endocrine system on bone and its growth plate are primarily indirect and mediated by its effect on intestinal calcium transport and serum calcium and phosphate homeostasis. Rickets and osteomalacia can be prevented by daily supplements of 400 IU of vitamin D. Vitamin D deficiency (serum 25-hydroxyvitamin D <50 nmol/L) accelerates bone turnover, bone loss, and osteoporotic fractures. These risks can be reduced by 800 IU of vitamin D together with an appropriate calcium intake, given to institutionalized or vitamin D-deficient elderly subjects. VDR and vitamin D metabolic enzymes are widely expressed. Numerous genetic, molecular, cellular, and animal studies strongly suggest that vitamin D signaling has many extraskeletal effects. These include regulation of cell proliferation, immune and muscle function, skin differentiation, and reproduction, as well as vascular and metabolic properties. From observational studies in human subjects, poor vitamin D status is associated with nearly all diseases predicted by these extraskeletal actions. Results of randomized controlled trials and Mendelian randomization studies are supportive of vitamin D supplementation in reducing the incidence of some diseases, but, globally, conclusions are mixed. These findings point to a need for continued ongoing and future basic and clinical studies to better define whether vitamin D status can be optimized to improve many aspects of human health. Vitamin D deficiency enhances the risk of osteoporotic fractures and is associated with many diseases. We review what is established and what is plausible regarding the health effects of vitamin D.
Topics: Animals; Bone and Bones; Calcium; Female; Humans; Male; Osteomalacia; Rickets; Signal Transduction; Vitamin D; Vitamin D Deficiency
PubMed: 30321335
DOI: 10.1210/er.2018-00126 -
Bone Jan 2022Contemporary intravenous iron formulations allow administration of high doses of elemental iron and enable correction of total iron deficit in one or two infusions. An... (Review)
Review
Contemporary intravenous iron formulations allow administration of high doses of elemental iron and enable correction of total iron deficit in one or two infusions. An important but underappreciated complication of certain formulations is hypophosphatemia caused by increased secretion of the phosphaturic hormone, fibroblast growth factor 23 (FGF23). The pathophysiology of FGF23-induced hypophosphatemia due to certain intravenous iron formulations has been recently investigated in prospective clinical trials. To reach the correct diagnosis, clinicians must recognize the typical clinical manifestations of intravenous iron-induced hypophosphatemia and identify a specific pattern of biochemical changes (hyperphosphaturic hypophosphatemia triggered by high FGF23 that causes low 1,25 (OH) vitamin D, hypocalcemia and secondary hyperparathyroidism). Physicians and patients should be aware of hypophosphatemia as a common complication of intravenous iron therapy and monitor serum phosphate concentrations in patients receiving repeated doses of specific intravenous iron formulations. Symptoms of hypophosphatemia are associated with severity and duration. Persistent hypophosphatemia can occur with iron therapy and can cause debilitating diseases including myopathy, osteomalacia and fractures. This review summarizes the current understanding of the iron-phosphate axis as well as complications of intravenous iron-induced hypophosphatemia.
Topics: Anemia, Iron-Deficiency; Fibroblast Growth Factors; Humans; Hypophosphatemia; Iron; Osteomalacia; Prospective Studies
PubMed: 34534708
DOI: 10.1016/j.bone.2021.116202 -
Endocrine Reviews May 2023Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and...
Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers (bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide); and commonly used resorption markers (serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen, and tartrate-resistant acid phosphatase type 5b). BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable factors (eg, age, gender, ethnicity) and controllable factors, particularly relating to collection conditions (eg, fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics, and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.
Topics: Humans; Collagen Type I; Acid Phosphatase; Alkaline Phosphatase; Bone Remodeling; Biology; Bone Resorption
PubMed: 36510335
DOI: 10.1210/endrev/bnac031 -
The Indian Journal of Medical Research Oct 2020Defective mineralization of the growth plate and preformed osteoid result in rickets and osteomalacia, respectively. The leading cause of rickets worldwide is solar... (Review)
Review
Defective mineralization of the growth plate and preformed osteoid result in rickets and osteomalacia, respectively. The leading cause of rickets worldwide is solar vitamin D deficiency and/or dietary calcium deficiency collectively termed as nutritional rickets. Vitamin D deficiency predominates in high-latitude countries in at-risk groups (dark skin, reduced sun exposure, infants and pregnant and lactating women) but is emerging in some tropical countries due to sun avoidance behaviour. Calcium deficiency predominates in tropical countries, especially in the malnourished population. Nutritional rickets can have devastating health consequences beyond bony deformities (swollen wrist and ankle joints, rachitic rosary, soft skull, stunting and bowing) and include life-threatening hypocalcaemic complications of seizures and, in infancy, heart failure due to dilated cardiomyopathy. In children, diagnosis of rickets (always associated with osteomalacia) is confirmed on radiographs (cupping and flaring of metaphyses) and should be suspected in high risk individuals with the above clinical manifestations in the presence of abnormal blood biochemistry (high alkaline phosphatase and parathyroid hormone, low 25-hydroxyvitamin D and calcium and/or low phosphate). In adults or adolescents with closed growth plates, osteomalacia presents with non-specific symptoms (fatigue, malaise and muscle weakness) and abnormal blood biochemistry, but only in extreme cases, it is associated with radiographic findings of Looser's zone fractures. Bone biopsies could confirm osteomalacia at earlier disease stages, for definitive diagnosis. Treatment includes high-dose cholecalciferol or ergocalciferol daily for a minimum of 12 wk or stoss therapy in exceptional circumstances, each followed by lifelong maintenance supplementation. In addition, adequate calcium intake through diet or supplementation should be ensured. Preventative approaches should be tailored to the population needs and incorporate multiple strategies including targeted vitamin D supplementation of at-risk groups and food fortification with vitamin D and/or calcium. Economically, food fortification is certainly the most cost-effective way forward.
Topics: Adolescent; Calcium; Child; Female; Humans; Infant; Lactation; Osteomalacia; Pregnancy; Rickets; Vitamin D; Vitamin D Deficiency; Vitamins
PubMed: 33380700
DOI: 10.4103/ijmr.IJMR_1961_19 -
Orthopaedics & Traumatology, Surgery &... Feb 2022The cause of Kienböck's disease is still unclear. It was initially considered as osteomalacia, before being recognized as avascular necrosis of the lunate. Its... (Review)
Review
The cause of Kienböck's disease is still unclear. It was initially considered as osteomalacia, before being recognized as avascular necrosis of the lunate. Its functional prognosis is doubtful, given that the progression often leads to wrist degeneration. Conservative treatment does not provide good results in adults; thus surgery is often needed. Certain anatomical factors such as the ulnar variance, configuration of the lunate or orientation of the radial glenoid have turned out not to contribute to necrosis but may contribute to lunate fracture. The lunate's vascularization can be precarious and mostly depends on the capsular arterioles. The lunate is a very mobile bone that participates in wrist movements, both in the radiocarpal joint and especially in the mid-carpal joints during activities of daily living. Radiographs are not the only diagnostic tools. The lunate makes contact with the radius and triangular fibrocartilage complex and is often subjected to high shear loads at the edge of the radius that can cause it to fracture. MRI and arthroscopy can contribute to the assessment. Kienböck's disease is likely an inflammatory, biological venous thrombosis disorder that leads to local damage due to intraosseous compartment syndrome. The basis of surgical treatment is to decompress the lunate to shield it from shear and compression loads. Existing osteotomy procedures will be described and compared to better understand their biomechanical effects. Some osteotomies do not reduce the loads transmitted to the lunate but can reduce the risk of intra-osseous shear. Some osteotomies may place excessive pressure on the lunate on its ulnar side. Some techniques are extra-articular and preserve the capsule's vascularization along with the anatomy of the mid-carpal joint. When the lunate damage is so severe that the bone's viability is compromised, bone grafting or replacement have been proposed. The palliative techniques typically used for wrist degeneration are indicated in the terminal stages. There are currently no effective biological treatments. While the origin of Kienböck's disease is still unknown, we now know that decompression osteotomies, while they do not heal the necrosis, protect the lunate from collapse, which hopefully provides enough time for biological healing to occur.
Topics: Activities of Daily Living; Adult; Fractures, Bone; Humans; Lunate Bone; Necrosis; Osteonecrosis; Radius; Ulna; Wrist Joint
PubMed: 34861414
DOI: 10.1016/j.otsr.2021.103161