Genetic studies on inherited tumor susceptibility disorders have increased our knowledge of tumorigenesis. PHPT is found in several disorders with an autosomal dominance inher­itance, such as multiple endocrine neoplasia type 1 (MEN 1) and 2A (MEN2A), hereditary hyperparathyroidism-jaw tumor (HPT-JT) syndrome, familial isolated hyperparathyroidism (FIHP), familial hypocalciuric hypercalcemia (FHH) and neona­tal severe hyperparathyroidism (NSHPT). The [...]

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Early studies of the clonal status of parathyroid tumors assessed X-chromosome inactivation patterns by measuring isoforms of glucose-6-phopshate dehydrogenase in parathyroid adenomas of women heterozygous for the polymorphism. These stud­ies indicated that parathyroid adenomas were polyclonal as op­posed to monoclonal growths. The issue of the clonal status of parathyroid tumors was reevaluated several years later, [...]

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Introduction Over the past ten years, our knowledge of the molecular basis of parathyroid neoplasia has increased substantially. Many of the well established general themes in tumor biology appear to be applicable to parathyroid tumorigenesis, in spite of the typi­cally nonmalignant status of these tumors. Patients with primary hyperparathyroidism (PHPT) have both an increased parathy­roid [...]

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Similarly to other genes polymorphisms, significant differ­ences exist in VDR polymorphisms distribution among differ­ent ethnic groups. A possible explanation to polymorphism generation phenomena is DNA damage events in an ancient small population that grow up in frequency becoming poly­morphisms in modern populations. VDR haplotypes distribu­tion reflects out-of-Africa evolution theory that describe hu­man populations origin and [...]

Continue reading " The vitamin D receptor: biological and molecular properties. VDR polymorphisms and its ethnic distribution "

Morrison and co-workers analysed an Australian population sample and evidenced the presence of association between al- lelic variants in the 3′ region (for B allele) and osteocalcin bone turnover marker levels in serum. Since 1992, several studies about correlation of VDR polymorphisms with BMD and bone turnover markers have been published, generating con­flicting data. In [...]

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Vitamin D endocrine system positively affects infection, autoim­mune diseases, tolerance in transplantation and this mainly de­rives from prodifferentiating effects on monocyte- macrophages, antigen-presenting cells, dendritic cells (DC) and lymphocytes as evidenced from in vivo and in vitro studies (Figure 4). One of the mechanisms mediating vitamin D function in resis­tance to infections is the already [...]

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Vitamin D acts in parathyroid tissue through its binding to VDR and consequent regulation of gene transcription and a VDRE was demonstrated in the promoter region of the PTH gene. Thus 1,25(OH)2D3 exerts a negative feedback on PTH production in response to PTH-dependent activation of calcium mobilization from kidney and bone, through a VDR-mediated silencing [...]

Continue reading " The vitamin D receptor: biological and molecular properties. Effects on parathyroid glands "