Several lines of evidence have suggested that the aggressiveness of MTC does not depend on the presence, absence or type of RET variant (which mainly affects the age at onset of the disease) but on the stage and the age at diagnosis of the disease [20], which are the strongest predictors of survival for patients with MTC; therefore, our data further support the appropriateness of the non-invasive screening recommended by current guidelines for healthy carriers of MOD risk level variants. The gene discussed is RET; the disease is medullary thyroid gland carcinoma.