The RET pathogenic variant (ENST00000355710.3) c.1900T>C) was identified in three related cases with a family history of thyroid cancer, providing a diagnosis of multiple endocrine neoplasia type 2 (MEN2), which is characterized by the development of medullary thyroid carcinoma [13]. The gene discussed is RET; the disease is multiple endocrine neoplasia type 2.