Primary hyperparathyroidism

Primary hyperparathyroidism is the third most frequent endocrine disorder. The condition required for diagnosis is inappropriately elevated secretion of parathyroid hormone (PTH) with respect to calcemia. Most often, the dise ase is due to a parathyroid adenoma, i.e. a monoclonal benign parathyroid t umor, less often to a parathyroid hyperplasia. The main tumorogenic mechani sms currently proposed are a DNA rearrangement in the PTH locus (transposit ion of the PTH promoter upstream to Cyclin D1/PRAD 1 gene) and a mutation o f the gene responsible for multiple endocrine neoplasia type I. The clinica l presentation has strikingly evolved towards a milder, asymptomatic form, frequently diagnosed on systematic screenings. Though the mechanism of hype rcalcemia is better understood, several hypothesis are still being consider ed about the regulation of tumoral PTH secretion : the role of the expressi on of calcium-receptor in parathyroid gland cells, vitamin D receptor and e strogen receptor polymorphisms, etc. Surgery is still advised far symptomat ic forms of the disease, either because of a bone involvement, or because o f an evolutive nephrolithiasis; In the near future, the new calcium-recepto r agonists could be a relevant therapeutic approach.