RET and medullary thyroid gland carcinoma: Rare synonymous changes in the RET gene, c.1827C>T (p.Cys609Cys), c.2364C>T (p.Ile788Ile), and c.2673G>A (p.Ser891Ser), were identified in MTC patients and c.2418C>T (p.Tyr806Tyr) in a patient suspected of MEN2.