Endocrine disruptor occur from low-dose exposure to exogenous hormones or hormonally active chemicals such as bisphenol A. These chemical can bind to receptors for other hormonally mediated processes. Furthermore, since endogenous hormones are already present in the body in biologically active concentrations, additional exposure to relatively small amounts of exogenous hormonally active substances can disrupt the proper functioning of the body's endocrine system. Thus, an endocrine disruptor can elicit adverse effects at much lower doses than a toxicity, acting through a different mechanism. The timing of exposure is also critical. Most critical stages of development occur in utero, where the fertilized egg
Multiple endocrine neoplasia type 2 are involved and selective resection of pathologic parathyroid glands for primary hyperparathyroidism. Familial genetic screening is recommended to identify at risk subjects who will develop the disease, permitting early management by performing prophylactic thyroidectomy, giving them the best chance of cure. Prognosis of MEN2 is mainly related to the stage-dependant prognosis of MTC indicating the necessity of a complete thyroid surgery for index cases with MTC and the early thyroidectomy for screened at risk subjects. Multiple endocrine neoplasia type 2 Multiple endocrine neoplasia type 2 (MEN2) (also known as "Pheochromocytoma and amyloid producing medullary thyroid carcinoma", "PTC syndrome," and "Sipple