However, in the event that multiple endocrine neoplasia 2A (MEN 2A), which is characterized by MTC, adrenal pheochromocytoma and hyperparathyroidism due to specific RET proto-oncogene mutations, remains unrecognized during pregnancy, then both woman and progeny are at risk of a crisis and of RET mutation transmission, respectively [13]. This evidence concerns the gene RET and medullary thyroid gland carcinoma.