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 40 years of age. There is significant intra- and inter-familial variability in the age of onset, severity of disease, and tumor types. Despite numerous studies, no genotype-phenotype correlations have been established, suggesting that unknown genetic and environmental modifiers are involved in the expression of the MEN1 phenotype. Multiple Endocrine Neoplasia type 1 (MEN1) is a rare hereditary endocrine cancer syndrome characterized primarily by tumors of the parathyroid glands (95% of cases), endocrine gastroenteropancreatic (GEP) tract (30-80% of cases), and anterior pituitary (15-90% of cases). Other endocrine and non-endocrine neoplasms including adrenocortical and thyroid tumors, visceral and cutaneous lipomas, meningiomas, facial