Interestingly, the p.Tyr791Phe RET variant that has been considered as a putative Slavic ancestry variant because of its high prevalence in the Czech Republic, Poland, and Central Europe has also been frequently reported in sporadic appearing and less aggressive MTC cases in Ashkenazi Jews, thus also implying a possible founder mutation [63] (Figure 1). This evidence concerns the gene RET and medullary thyroid gland carcinoma.