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Parathyroid hormone‐related protein in the aetiology of fibrous dysplasia of bone in the McCune Albright syndrome
Author(s) -
Fraser William D.,
Walsh Cathy A.,
Birch Mark A.,
Durham Brian,
Dillon Jane P.,
McCreavy David,
Gallagher James A.
Publication year - 2000
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.2000.01112.x
Subject(s) - medicine , endocrinology , parathyroid hormone related protein , parathyroid hormone , immunoradiometric assay , vitamin d and neurology , in vitro , fibrous dysplasia , messenger rna , hormone , chemistry , calcium , radioimmunoassay , pathology , gene , biochemistry
OBJECTIVE Fibrous dysplasia, observed in bone lesions in the McCune Albright syndrome (MAS), is thought to result from abnormalities in cells of the osteogenic lineage associated with over‐activation of the cAMP signalling pathway in affected cells. The aim of this study was to investigate the role of parathyroid hormone‐related protein (PTHrP) in the aetiology of MAS, and to determine a possible therapeutic role for 1,25‐dihydroxy vitamin D 3 (1,25(OH) 2 D 3 ). DESIGN The effects of 1,25(OH) 2 D 3 on PTHrP production and mRNA expression were determined in vitro . 1,25(OH) 2 D 3 therapy was administered to three patients with MAS. PATIENTS Clinical data from four MAS patients (MAS1, 2, 3 and 4), and in vitro studies using bone from three MAS patients (MAS1, 2, and 3), are presented. MEASUREMENTS Immunoradiometric assay and low‐cycle number reverse transcriptase‐linked PCR were used to determine PTHrP production and mRNA expression in vitro . Standard clinical biochemistry was recorded pre and post commencement of 1,25(OH) 2 D 3 treatment. RESULTS We report the elevated secretion of PTHrP, and a concomitant rise in PTHrP mRNA expression, in cultured osteoblasts from three MAS patients. Treatment with 1,25(OH) 2 D 3 produced a dose‐dependent decrease in PTHrP protein secretion and mRNA expression. Marked improvement in bone biochemistry in MAS1, 2 and 3 post treatment with 1,25(OH) 2 D 3 is documented. CONCLUSION This study provides the first evidence suggesting that PTHrP may contribute to the aetiology of fibrous dysplasia in MAS. In addition, the therapeutic administration of 1,25(OH) 2 D 3 may provide clinicians with an important new regime for symptomatic relief of bone pain and fracture in some patients with MAS.