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Lecoq AL, Brandi ML, Linglart A, Kamenický P. Management of X-linked hypophosphatemia in adults. Metabolism 2020; 103S:154049. [PMID: 31863781 DOI: 10.1016/j.metabol.2019.154049] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/23/2019] [Accepted: 11/25/2019] [Indexed: 11/27/2022]
Abstract
X-linked hypophosphatemia (XLH) is caused by mutations in the PHEX gene which result in Fibroblast Growth Factor-23 (FG-F23) excess and phosphate wasting. Clinically, XLH children present with rickets, bone deformities and short stature. In adulthood, patients may still be symptomatic with bone and joint pain, osteomalacia-related fractures or pseudofractures, precocious osteoarthrosis, enthesopathy, muscle weakness and severe dental anomalies. Besides these musculoskeletal and dental manifestations, adult XLH patients are also prone to secondary and tertiary hyperparathyroidism, cardiovascular and metabolic disorders. Pathophysiology of hyperparathyroidism is only partially understood but FGF23 excess and deficient production of calcitriol likely contributes to its development. Similarly, the pathophysiological mechanisms of potential cardiovascular and metabolic involvements are not clear, but FGF-23 excess may play an essential role. Treatment should be considered in symptomatic patients, patients undergoing orthopedic or dental surgery and women during pregnancy and lactation. Treatment with oral phosphate salts and active vitamin D analogs has incomplete efficacy and potential risks. Burosumab, a recombinant human monoclonal antibody against FGF-23, has proven its efficacy in phase 2 and phase 3 clinical trials in adult patients with XLH, but currently its position as first line or second line treatment differ among the countries.
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Affiliation(s)
- Anne-Lise Lecoq
- AP-HP, Department of Endocrinology and Reproductive Diseases, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Maria Luisa Brandi
- Department of Surgery and Translational Medicine, University of Florence, University Hospital of Florence, Florence, Italy
| | - Agnès Linglart
- AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France; Université Paris-Saclay, INSERM, Physiologie et Physiopathologie Endocriniennes, Le Kremlin-Bicêtre, France
| | - Peter Kamenický
- AP-HP, Department of Endocrinology and Reproductive Diseases, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France; Université Paris-Saclay, INSERM, Physiologie et Physiopathologie Endocriniennes, Le Kremlin-Bicêtre, France.
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Rafaelsen S, Johansson S, Ræder H, Bjerknes R. Hereditary hypophosphatemia in Norway: a retrospective population-based study of genotypes, phenotypes, and treatment complications. Eur J Endocrinol 2016; 174:125-36. [PMID: 26543054 PMCID: PMC4674593 DOI: 10.1530/eje-15-0515] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 11/04/2015] [Indexed: 01/14/2023]
Abstract
OBJECTIVE Hereditary hypophosphatemias (HH) are rare monogenic conditions characterized by decreased renal tubular phosphate reabsorption. The aim of this study was to explore the prevalence, genotypes, phenotypic spectrum, treatment response, and complications of treatment in the Norwegian population of children with HH. DESIGN Retrospective national cohort study. METHODS Sanger sequencing and multiplex ligand-dependent probe amplification analysis of PHEX and Sanger sequencing of FGF23, DMP1, ENPP1KL, and FAM20C were performed to assess genotype in patients with HH with or without rickets in all pediatric hospital departments across Norway. Patients with hypercalcuria were screened for SLC34A3 mutations. In one family, exome sequencing was performed. Information from the patients' medical records was collected for the evaluation of phenotype. RESULTS Twety-eight patients with HH (18 females and ten males) from 19 different families were identified. X-linked dominant hypophosphatemic rickets (XLHR) was confirmed in 21 children from 13 families. The total number of inhabitants in Norway aged 18 or below by 1st January 2010 was 1,109,156, giving an XLHR prevalence of ∼1 in 60,000 Norwegian children. FAM20C mutations were found in two brothers and SLC34A3 mutations in one patient. In XLHR, growth was compromised in spite of treatment with oral phosphate and active vitamin D compounds, with males tending to be more affected than females. Nephrocalcinosis tended to be slightly more common in patients starting treatment before 1 year of age, and was associated with higher average treatment doses of phosphate. However, none of these differences reached statistical significance. CONCLUSIONS We present the first national cohort of HH in children. The prevalence of XLHR seems to be lower in Norwegian children than reported earlier.
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Affiliation(s)
- Silje Rafaelsen
- Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway
| | - Stefan Johansson
- Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway
| | - Helge Ræder
- Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway
| | - Robert Bjerknes
- Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway Section for PediatricsDepartment of Clinical Science, Haukeland University Hospital, University of Bergen, N-5021 Bergen, NorwayCenter for Medical Genetics and Molecular MedicineDepartment of PediatricsHaukeland University Hospital, Bergen, Norway
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Levine BS, Kleeman CR, Felsenfeld AJ. The journey from vitamin D-resistant rickets to the regulation of renal phosphate transport. Clin J Am Soc Nephrol 2009; 4:1866-77. [PMID: 19808223 DOI: 10.2215/cjn.03000509] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In 1937, Fuller Albright first described two rare genetic disorders: Vitamin D resistant rickets and polyostotic fibrous dysplasia, now respectively known as X-linked hypophosphatemic rickets (XLH) and the McCune-Albright syndrome. Albright carefully characterized and meticulously analyzed one patient, W.M., with vitamin D-resistant rickets. Albright subsequently reported additional carefully performed balance studies on W.M. In this review, which evaluates the journey from the initial description of vitamin D-resistant rickets (XLH) to the regulation of renal phosphate transport, we (1) trace the timeline of important discoveries in unraveling the pathophysiology of XLH, (2) cite the recognized abnormalities in mineral metabolism in XLH, (3) evaluate factors that may affect parathyroid hormone values in XLH, (4) assess the potential interactions between the phosphate-regulating gene with homology to endopeptidase on the X chromosome and fibroblast growth factor 23 (FGF23) and their resultant effects on renal phosphate transport and vitamin D metabolism, (5) analyze the complex interplay between FGF23 and the factors that regulate FGF23, and (6) discuss the genetic and acquired disorders of hypophosphatemia and hyperphosphatemia in which FGF23 plays a role. Although Albright could not measure parathyroid hormone, he concluded on the basis of his studies that showed calcemic resistance to parathyroid extract in W.M. that hyperparathyroidism was present. Using a conceptual approach, we suggest that a defect in the skeletal response to parathyroid hormone contributes to hyperparathyroidism in XLH. Finally, at the end of the review, abnormalities in renal phosphate transport that are sometimes found in patients with polyostotic fibrous dysplasia are discussed.
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Affiliation(s)
- Barton S Levine
- Department of Medicine, VA Greater Los Angeles Healthcare System, and David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90073, USA.
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An Unusual Case of Autonomous Hyperparathyroidism in a Patient With X-Linked Hypophosphatemic Rickets and Kallmann Syndrome. Am J Med Sci 2009; 337:134-7. [DOI: 10.1097/maj.0b013e31816ecb00] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Knudtzon J, Halse J, Monn E, Nesland A, Nordal KP, Paus P, Seip M, Sund S, Sødal G. Autonomous hyperparathyroidism in X-linked hypophosphataemia. Clin Endocrinol (Oxf) 1995; 42:199-203. [PMID: 7704964 DOI: 10.1111/j.1365-2265.1995.tb01863.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Four patients with familial hypophosphataemic rickets developed significant hypercalcaemia which persisted after discontinuation of vitamin D therapy. They had increased PTH levels and were operated for hyperparathyroidism at the ages of 18, 20, 24 and 45 years, respectively. Three of the patients had previously received phosphate treatment and one patient developed hyperparathyroidism 7 years after treatment with calcitriol. Histological evaluation revealed different degrees of parathyroid hyperplasia in all patients, with persistently increased PTH and/or calcium levels after surgery. The possibility of autonomous hyperparathyroidism should be evaluated in the follow-up of patients with X-linked hypophosphataemic rickets.
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Affiliation(s)
- J Knudtzon
- Department of Endocrinology, Rikshospitalet, Oslo, Norway
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Pettifor JM. Recent advances in pediatric metabolic bone disease: the consequences of altered phosphate homeostasis in renal insufficiency and hypophosphatemic vitamin D-resistant rickets. BONE AND MINERAL 1990; 9:199-214. [PMID: 2163713 DOI: 10.1016/0169-6009(90)90038-h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Over the past decade our understanding of the pathogenesis of altered mineral homeostasis in chronic renal failure (CRF) and X-linked hypophosphatemic vitamin D-resistant rickets (XLH) has increased, and has provided a rational approach for the use of the 1 alpha-hydroxylated analogues of vitamin D in their therapy. Recent evidence suggests that intracellular phosphate (Pi) retention in CRF plays a major role in decreasing serum 1,25-dihydroxyvitamin D (1,25(OH)2D) levels, which are responsible for the progressive rise in serum parathyroid hormone (PTH) concentrations through the direct action of 1,25(OH)2D on the parathyroid gland. 1,25(OH)2D levels affect the number of intracellular 1,25(OH)2D receptors, preproPTH mRNA levels and the set point for calcium suppression of PTH release. Further in experimental CRF, the maintenance of normal 1,25(OH)2D levels prevents parathyroid gland hyperplasia. These studies indicate that depressed renal 1 alpha-hydroxylase activity due to Pi retention is a major factor in directly increasing PTH secretion, which in turn contributes significantly to the severity of renal osteodystrophy. Thus the aim of therapy in early CRF should be to maintain normal levels of 1,25(OH)2D which can be achieved by either dietary Pi restriction and oral Pi binders or by administering small doses of 1 alpha-hydroxylated metabolites. The long term consequences of these two different therapeutic regimens still need to be assessed. In XLH, evidence is rapidly accumulating that alterations in 1 alpha-hydroxylase activity secondary to impaired Pi handling by the proximal renal tubule, results in decreased serum 1,25(OH)2D levels, which might be responsible for a number of the associated abnormalities documented in both treated and untreated XLH patients. These abnormalities include decreased calcium and Pi absorption by the intestine and low normal serum calcium values. In vitamin D- and Pi-treated patients 1,25(OH)2D levels are further depressed, with a resultant increase in PTH values, and the development of tertiary hyperparathyroidism in a small number of patients. The use of 1 alpha-hydroxylated analogues rather than vitamin D together with Pi supplements decreases the severity of hyperparathyroidism, improves Pi absorption from the intestine and markedly ameliorates the degree of osteomalacia. Whether long-term therapy with these analogues will prevent the development of tertiary hyperparathyroidism in patients with XLH is unclear.
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Affiliation(s)
- J M Pettifor
- Department of Paediatrics, University of the Witwatersrand, Johannesburg, South Africa
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Ando M, Matsui S, Jinno H, Sayato Y, Takeda M. Generation of hypophosphatemia in rats by continuous oral administration of cadmium. Toxicology 1988; 53:1-10. [PMID: 3201471 DOI: 10.1016/0300-483x(88)90231-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
To obtain further information on the negative calcium balance caused by cadmium (Cd), the factors associated with serum calcium and phosphorus homeostasis other than inhibition of intestinal calcium absorption were studied by using parathyroid hormone (PTH) and 1 alpha-hydroxycholecalciferol (1 alpha-OH-D3). In rats exposed to Cd for 30 or 90 days, the concentrations of serum calcium after treatment with PTH, parathyroidectomy (PTX) or 1 alpha-OH-D3 showed almost the same patterns as those of control animals. It was considered that the mechanism of regulation of calcium in Cd-exposed rats was normal. The continuous oral administration of Cd generated hypophosphatemia in rats. On the other hand, in 30- and 90-day-treated rats, the low concentration of serum phosphorus caused by Cd was further decreased by administration of PTH, whereas it was increased by PTX. The hypophosphatemia found in rats exposed to Cd for 30 days, but not for 90 days, was reversed by treatment with 1 alpha-OH-D3. From these results, it was concluded that the hypophosphatemia caused by long term oral administration of Cd resulted from secondary hyperparathyroidism, due to inhibited calcium absorption from the intestine, as was demonstrated previously.
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Affiliation(s)
- M Ando
- National Institute of Hygienic Sciences, Tokyo, Japan
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Posillico JT, Lobaugh B, Muhlbaier LH, Drezner MK. Abnormal parathyroid function in the X-linked hypophosphatemic mouse. Calcif Tissue Int 1985; 37:418-22. [PMID: 3930040 DOI: 10.1007/bf02553712] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Employing a cytochemical bioassay, we compared parathyroid function in normal and X-linked hypophosphatemic (Hyp) mice. Under basal conditions Hyp mice manifested hypocalcemia and, in accord, had a plasma bioactive parathyroid hormone concentration (3.04 +/- 0.14 pg/ml) significantly greater than that of normals (2.16 +/- 0.14 pg/ml). We confirmed the validity of the bioassay by demonstrating that the plasma collected from both mouse models diluted parallel to the assay standard curve. Moreover, after parathyroidectomy, normal and Hyp mice had plasma bioactive parathyroid hormone levels approximately 90% less than those obtained under basal conditions and indistinguishable from one another. In further studies we observed that dietary calcium and/or vitamin D deprivation in both animal models resulted in a comparable decline of the plasma calcium concentration. However, the concordant increase of the circulating bioactive parathyroid hormone level was greater in the normal mice. Thus, the bioactive parathyroid hormone concentration obtained in response to a low calcium challenge in normals was significantly greater than that in Hyp mice. In contrast, in response to dietary calcium loading, the plasma bioactive parathyroid hormone levels did not decrease significantly from basal values in either animal model. These data illustrate that the bioactive parathyroid hormone concentration in both normal and Hyp mice is inversely correlated with the plasma calcium. However, while the Hyp mice maintain an elevated plasma parathyroid hormone concentration under basal conditions (in response to a decreased plasma calcium), the parathyroid activity of the mutants after a more severe hypocalcemic challenge is attenuated, resulting in a significantly different model of linear correlation. Thus, these data indicate that Hyp mice manifested abnormal regulation of parathyroid function.
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Brunette MG. Metabolic abnormalities underlying the pathogenesis of vitamin D resistant rickets (VDRR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1982; 151:33-40. [PMID: 6295093 DOI: 10.1007/978-1-4684-4259-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Marie PJ, Glorieux FH. Histomorphometric study of bone remodeling in hypophosphatemic vitamin D-resistant rickets. METABOLIC BONE DISEASE & RELATED RESEARCH 1981; 3:31-8. [PMID: 6267414 DOI: 10.1016/s0221-8747(81)80020-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Static and dynamic histomorphometric parameters were evaluated on undecalcified iliac crest bone biopsies obtained from eight children with untreated hypophosphatemic vitamin D resistant rickets (VDRR) in an attempt to evaluate whether a primary metabolic bone defect contributes to the skeletal disorder observed in that disease. When compared to normal age-matched controls the trabecular calcified bone volume was not decreased and there was no evidence of excessive osteoclastic resorption. Both trabecular and cortical bone envelopes had an excess of osteoid tissue and a decreased extent of the mineralization front. Dual tetracycline labeling revealed a decrease in the osteoblastic calcification rate and a marked prolongation of the mineralization lag time and of the formation period. In the intracortical Haversian system the birthrate of new Basic Multicellular remodeling Units (BMU) was markedly reduced, leading to a marked depression of the bone formation rate at the whole tissue level. The combination of the decreased birthrate of new BMU and the prolonged formation period appears to be characteristic of the disease. These results indicate that abnormal differentiation and function of the osteoblast contribute to the osteomalacic lesion present in VDRR. Defective mineralization and impaired osteoblastic function might be the consequence of the chronic hypophosphatemic state. However, the existence of a primary disorder of the bone cell line cannot be excluded as an explanation of the defective recruitment and function of the bone forming cells.
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Cartwright DW, Latham SC, Masel JP, Yelland JD. Spinal canal stenosis in adult with hypophosphataemic vitamin D-resistant rickets. AUSTRALIAN AND NEW ZEALAND JOURNAL OF MEDICINE 1979; 9:705-8. [PMID: 231427 DOI: 10.1111/j.1445-5994.1979.tb04205.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A case is described of a 55-year-old male with hypophosphataemic vitamin D-resistant rickets, who presented with long-standing back pain and paraesthesiae in both legs considered to be due to osteoid encroachment on an already narrow spinal canal. Marked symptomatic improvement has followed extensive lumbar laminectomy.
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13
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Brunette MG, Giasson SD, Vigneault N, Carriere S. Micropuncture study of phosphorus transport in genetic hypophosphatemic mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1978; 103:91-6. [PMID: 717127 DOI: 10.1007/978-1-4684-7758-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Giasson SD, Brunette MG, Danan G, Vigneault N, Carriere S. Micropuncture study of renal phosphorus transport in hypophosphatemic vitamin D resistant rickets mice. Pflugers Arch 1977; 371:33-8. [PMID: 201919 DOI: 10.1007/bf00580769] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Krohn HP, Offermann G, Brandis M, Brodehl J, Hanke K, Offner G. Occurrence of hyperparathyroidism in children with X-linked hypophosphatemia under treatment with vitamin D and phsophate. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1977; 81:345-51. [PMID: 899930 DOI: 10.1007/978-1-4613-4217-5_34] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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O'Doherty PJ, DeLuca HF. Intestinal calcium and phosphate transport in genetic hypophosphatemic mice. Biochem Biophys Res Commun 1976; 71:617-21. [PMID: 962943 DOI: 10.1016/0006-291x(76)90832-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Cuisnier-Gleizes P, Thomasset M, Sainteny-Debove F, Mathieu H. Phosphorus deficiency, parathyroid hormone and bone resorption in the growing rat. CALCIFIED TISSUE RESEARCH 1976; 20:235-49. [PMID: 953782 DOI: 10.1007/bf02546412] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sham-operated and parathyroidectomized (PTX) rats were divided into two pair-fed groups, one on a normal mineral intake (0.5% Ca, 0.3% P), the other on a regimen low in phosphorus (0.5% Ca, 0.03% P). P depletion led to a drop in plasma P and urine P, a rise in plasma Ca and a marked rise in urine Ca, a drop in serum magnesium and a rise in urine Mg. The changes were more pronounced in the PTX animals, but final values were the same in both groups. Parallel bone-seeking isotope (85Sr, 177Lu, 237Np) studies in nonablated animals revealed an increase in the urinary nuclide output and in the urine/tibia ratio in P-deficient animals. Normal and primary bone osteocytes decreased and enlarged osteocytes increased as a result of P deficiency; osteoclasts and osteoblasts also increased. Bone composition showed a drop in ash content and a rise in water, with a light decrease in both Ca and P, and a corresponding rise in hydroxyproline and nitrogen in the P-deficient animals. The results are interpreted to mean that P-deficiency in the young growing rat leads to an increase in bone resorption which occurs also in the absence of parathyroid hormone (PTH). The fact that final values were similar in the control and PTX P-deficient animals suggests that steady-state regulation can also occur without PTH. Because P-deficiency leads to rapid hypercalcemia and rapid marked hypercalciuria, there may exist a mechanism for phosphate regulation which would then supersede Ca homeostasis. The change in serum and urine Mg levels may reflect a decrease in tubular Ca and Mg reabsorption associated with P-deficiency.
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Stamp TC, Baker LR. Recessive hypophosphataemic rickets, and possible aetiology of the 'vitamin D-resistant' syndrome. Arch Dis Child 1976; 51:360-5. [PMID: 180907 PMCID: PMC1545986 DOI: 10.1136/adc.51.5.360] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Two out of 3 children of a first-cousin marriage presented with severe rickets in infancy and are now adult. Their disease has shown continued activity, marked resistance to treatment with vitamin D, early fusion of cranial sutures, greatly increased bone density, nerve deafness, and life-long hypophosphataemia unaffected by treatment. Both parents and a third sib were normal clinically and biochemically. Blood grouping supported both stated paternity and parental consanguinity. Genetics of this unique disease can only be explained satisfactorily on the basis of autosomal recessive transmission, a mode not previously reported in primary hypophosphataemia. This homozygous disease resembles an exaggerated form of common X-linked rickets, though it is caused by a different gene. Although rare, it is particularly important because of the information it provides on the pathogenesis of both forms. We propose that both syndromes may result from multiple target organ unresponsiveness to 1,25-dihydroxycholecalciferol in intestine, kidney, bone, and parathyroid gland.
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Abstract
Abnormalities of calcium and mineral metabolism are described in relation to the differential diagnosis, clinical characteristics, diagnostic procedures, and treatment of infants and children with hypocalcemia, hypercalcemia, rickets, chronic renal insufficiency, and other disorders of calcium metabolism. Understanding of the basic pathogenesis of each abnormality of calcium homeostasis is essential for the rational management of affected patients.
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Tsang RC, Chen IW, McEnery P, Brown DR, Johnson JR, Lesniewicz J. Parathyroid function tests with EDTA infusions in infancy and childhood. J Pediatr 1976; 88:250-6. [PMID: 175144 DOI: 10.1016/s0022-3476(76)80990-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To determine the functional capabilities of the parathyroid glands, 17 EDTA infusions were given to 11 children (ages 1 month to 12 years) and to two mothers of four of the children. Serum ionized Ca fell from 4.1 mg/dl to 3.4 mg/dl. Excessive parathyroid hormone responses were elicited during seven of nine EDTA infusions in five children and in one adult with hypophosphatemic rickets, during the active phase of rickets. In four of five subjects with problems related to hypercalcemia, borderline low or undetectable PTH responses were elicited. Three relatively normal PTH responses were obtained, two in an infant after phosphate-induced hypocalcemic tetany was corrected, and one in a child with a malabsorption syndrome. The renal tubular reabsorption of phosphate was inversely related and the urinary cyclic AMP excretion was positively related to the PTH response. Thus EDTA infusions in infants and children might be useful in the identification of hyper-, normo-, or hypoparathyroid states and would be of value in defining the functional condition of the parathyroid glands in children with deranged Ca or P metabolism.
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Fischer JA, Blum JW, Hunziker W, Binswanger U. Regulation of circulating parathyroid hormone levels: normal physiology and consequences in disorders of mineral metabolism. KLINISCHE WOCHENSCHRIFT 1975; 53:939-54. [PMID: 1202277 DOI: 10.1007/bf01614437] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A review of the chemistry, the biosynthesis, the regulation of the secretion and the metabolism of parathyroid hormone (PTH) provides a background to problems related to the determination of immunoreactive PTH levels in the blood of normal subjects and of patients suffering from disorders of mineral metabolism. Immunoreactive PTH measurements have to be interpreted in the light of the immunoheterogeneity encountered and the occurrence of several circulating PTH species with different molecular weights and immunological properties.
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Colombo JP, Donath A. The effect of calcium infusions on renal handling of amino acids in hypophosphatemic vitamin D resistant rickets. ACTA PAEDIATRICA SCANDINAVICA 1975; 64:703-8. [PMID: 1166791 DOI: 10.1111/j.1651-2227.1975.tb03908.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Amino acid clearances were studied in four patients with hypophosphatemic vitamin D resistant rickets. T,e clearances of the single amino acids in the patients did not differ from that of control individuals for all amino acids tested. The reabsorption of amino acids and phosphate was further investigated with the use of calcium infusions. Under these conditions there was a significant decrease in the filtered fraction of phosphate and amino acid excreted in the vitamin D resistant group suggesting a depression of parathyroid hormone secretion. It seems likely, as demonstrated in the vitamin D resistant group, that in this disorder the renal tubule is particularly sensitive to changes in parathyroid hormone secretion in respect to amino acid reabsorption.
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Glorieux FH, Scriver CR. Letter: Parathyroid hormone secretion in X-linked hypophosphatemia. N Engl J Med 1974; 290:1329-30. [PMID: 4827642 DOI: 10.1056/nejm197406062902328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Brickman AS, Coburn JW, Kurokawa K, Bethune JE, Harrison HE, Norman AW. Actions of 1,25-dihydroxycholecalciferol in patients with hypophosphatemic, vitamin-D-resistant rickets. N Engl J Med 1973; 289:495-8. [PMID: 4353218 DOI: 10.1056/nejm197309062891002] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Kleeman CR, Better OS. Disordered divalent ion metabolism in kidney disease: comments on pathogenesis and treatment. Kidney Int 1973; 4:73-9. [PMID: 4364428 DOI: 10.1038/ki.1973.85] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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