*4.1. Patients*

From 2002 to 2020, in our laboratory, *RET* molecular analysis was performed in a total of 163 subjects, 102 of which underwent a complete gene analysis, while in the other 61, the targeted search for a family mutation was performed. In total, 120 of these subjects had participated in genetic counseling at our Cancer Genetics Clinic in Bologna based on personal history of a possible *RET*-related condition or identification of a *RET* mutation in the family; after verifying the presence of criteria for *RET* testing, informed consent was collected and a venous blood sample was drawn. For the other 43 subjects, blood sample was sent to our laboratory by external centers with the request for *RET* analysis, after informed consent had been collected by the requesting physician.
