Evidence for the founder effect of RET533 as the common Greek and Brazilian ancestor spreading multiple endocrine neoplasia 2A

Objectives About one-quarter of patients with medullary thyroid cancer (MTC) have inherited disease due to mutations in the RET gene. A rare mutation in exon 8 (G533C) of RET, previously described in a large Brazilian family with MEN2A, also appeared to be clustering in Greece, whereas it was rarely reported in other ethnic groups. The aim of this study was to identify a possible common ancestry between these carriers. Patients and methods Twelve RET G533C mutation carriers, four randomly selected from the Brazilian cohort and eight from apparently unrelated Greek families, were studied for a possible common ancestral origin. RET flanking microsatellite markers at chromosome 10q (D10S197, D10S196, D10S1652 and D10S537) were used. Results Genomic DNA analysis using these markers showed that many of these apparently unrelated individuals shared a common haplotype indicating a common ancestral origin. Conclusion Our data suggest that Brazilian and Greek patients with MTC carrying the G533C mutation in exon 8 of RET gene originate from a common ancestor. Due to historical reasons, we speculate that the more plausible explanation for the origin of this mutation is in Greece.