MEN 2A families: from hot spots to hot regions.

The aim of this study was to look for common ancestors among MEN 2A Portuguese families presenting with the same germ-line mutation of the RET proto-oncogene. To address this question from a genetic point of view, we performed haplotype analysis in six out of nine, apparently separate, MEN 2A families using four polymorphic markers. Three families carrying the C634R mutation and presenting the same phenotype shared the same haplotype surrounding the MEN 2A mutation. Moreover, these families were originally from the same geographic region although settled at different places along the country. Altogether, data suggested a common ancestral MEN 2A chromosome for three families. Since MEN 2A is a rare inherited cancer syndrome, identification of common ancestors may draw attention for specific geographic regions from where other affected families may arise at a higher chance and, therefore, termed 'hot regions'.