Introduction: Mutations in the ret gene are responsible for the transmission of inherited medullary thyroid cancer (MTC). In recent years a high prevalence of the rare exon 8 mutation (G533C) has been found in patients with inherited MTC in Greece. The aim of this study was to record with more detail the place of origin of these families in the country.
Design: We analysed the details of 44 patients belonging to 22 families who were carriers of the ret G533C mutation. Data concerning their place of origin as well as that of their ancestors were collected. Patients were distributed in four age groups (G1-4) according to age at diagnosis.
Results: The age at diagnosis was 21.0±2.9 (youngest age group G1, n=4), 37.7±5.5(G2, n=30), 54.1±4.4 (G3, n=8), 72.5±0.7 (G4, oldest, n=2) years. The patients belonged to 22 families, 15 of which were index cases diagnosed in our centre. Twelve belonged to G2, two to G3 and one in G4. Hot spots for the origin of these families were recognized. Nine families originated from central/western Greece in an area around Lake Trichonis, and Fokis, nine originated from Peloponese (Lakonia (mount Parnon region) and Arcadia), three from the Attika region (two from Pireaus) and four families from Asia Minor, all of them without any recognised familial relationship. No phenotype or outcome differences were found between the families from the various regions.
Conclusions: The majority of the ret gene exon8 (G533C) carriers originate from Central/Western Greece and Peloponese. Increased awareness for inherited disease is required for patients with apparently sporadic MTC originating from these areas, as the age at presentation is usually delayed (2570 years).