The Role of Mutant UDP-N-Acetyl-α-d-Galactosamine-Polypeptide N-Acetylgalactosaminyltransferase 3 in Regulating Serum Intact Fibroblast Growth Factor 23 and Matrix Extracellular Phosphoglycoprotein in Heritable Tumoral Calcinosis
| Autor: | Bhaskar Dasgupta, Mohamad S. Draman, Holly J. Garringer, Daniel L. Koller, Niamh Conlon, Siobhan I. Davis, Neal S. Fedarko, Alka Jain, Kenneth E. White, Corinne Fisher, M. J. Cullen, Tobias E. Larsson |
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| Rok vydání: | 2006 |
| Předmět: |
Fibroblast growth factor 23
medicine.medical_specialty medicine.drug_class Endocrinology Diabetes and Metabolism Molecular Sequence Data Clinical Biochemistry Polypeptide N-acetylgalactosaminyltransferase Biology Biochemistry Phosphates chemistry.chemical_compound Endocrinology Calcitriol Internal medicine medicine Extracellular Humans Carbonic anhydrase inhibitor Amino Acid Sequence Fibroblast Glycoproteins Extracellular Matrix Proteins Base Sequence Biochemistry (medical) Calcinosis Phosphoproteins medicine.disease Neoplasm Proteins Phosphate binder Fibroblast Growth Factors Fibroblast Growth Factor-23 medicine.anatomical_structure chemistry Galactosamine Mutation Tumoral calcinosis N-Acetylgalactosaminyltransferases |
| Zdroj: | The Journal of Clinical Endocrinology & Metabolism. 91:4037-4042 |
| ISSN: | 1945-7197 0021-972X |
| DOI: | 10.1210/jc.2006-0305 |
| Popis: | Context: Familial tumoral calcinosis (TC) results from disruptions in phosphate metabolism and is characterized by high serum phosphate with normal or elevated 1,25 dihydroxyvitamin vitamin D concentrations and ectopic and vascular calcifications. Recessive loss-of-function mutations in UDP-N-acetyl-α-d-galactosamine-polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) and fibroblast growth factor-23 (FGF23) result in TC. Objective: The objective of the study was to determine the relationship between GALNT3 and FGF23 in familial TC. Design, Setting, and Patients: We assessed the major biochemical defects and potential genes involved in patients with TC. Intervention: Combination therapy consisted of the phosphate binder Sevelamer and the carbonic anhydrase inhibitor acetazolamide. Results: We report a patient homozygous for a GALNT3 exon 1 deletion, which is predicted to truncate the encoded protein. This patient had high serum FGF23 concentrations when assessed with a C-terminal FGF23 ELISA but low-normal FGF23 levels when tested with an ELISA for intact FGF23 concentrations. Matrix extracellular phosphoglycoprotein has been identified as a possible regulator of phosphate homeostasis. Serum matrix extracellular phosphoglycoprotein levels, however, were normal in the family with GALNT3-TC and a kindred with TC carrying the FGF23 S71G mutation. The tumoral masses of the patient with GALNT3-TC completely resolved after combination therapy. Conclusions: Our findings demonstrate that GALNT3 inactivation in patients with TC leads to inadequate production of biologically active FGF23 as the most likely cause of the hyperphosphatemic phenotype. Furthermore, combination therapy may be effective for reducing the tumoral burden associated with familial TC. |
| Databáze: | OpenAIRE |
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