Abstract
Extracellular calcium ion concentration is regulated by the actions of parathyroid hormone (PTH) on kidney and bone, and parathyroid disorders can be classified according to whether they arise from an excess of PTH, or a deficiency, or insensitivity to PTH. Molecular gentic studies of parathyroid disorders have enabled the characterisation of some of the mechanisms involved in the regulation of parathyroid development, proliferation and PTH secretion. Thus, mutations in the calcium-sensing receptor gene have been reported in patients with familial benign hypercalcaemia (FBH) and autosomal dominant hypocalcaemia, and the roles of the oncogenes PRADl, which encodes a novel cyclin, and of the multiple endocrine neoplasia type 1 (MENl) gene have been revealed in the pathogenesis of some parathyroid turnours. In addition, mntations in the PTH gene and the mitochondrial genome have been demonstrated to be associated with some forms of hypoparathyroidism, mutations in the PTH receptor have been identified in Jansen’s and Bloomstrand’s chondrodysplasia, and mutations in the stimulatory G protein _~__ (Gsa) have been demonstrated in some patients with the McCune-Albright syndrome, pseudohypoparathyroidism type la and pseudo-pseudohypoparathyroidism type lb have been identified. The locations of other suseptibility genes, for example the hereditary hyperparathyroidism and jaw tumours (HPTJT) syndrome has been identified on chromosome lq21-q31, and genetic heterogeneity in the FBH, DiGeorge and William’ syndrome has been established. These molecular genetic studies have provided unique opportunities to elucidate the pathogenesis of some diseases of the parathyroids, and their role in calcium and bone metabohsm.
Published Version
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