Endocrine Abstracts

Approximately 25% of the reported cases of MTC are familial. Familial MTC can occur as part of MEN2-syndrome or as familial MTC alone (fMTC) defined as more than ten carriers in the kindred, or multiple carriers or affected members over the age of 50 with an adequate medical history excluding pheochromocytoma. The vast majority of MEN2 families (98%), as well as fMTC kindreds (88%) harbour a RET mutation. In MEN2A, mutations at codon-634 (exon-11) account for 85% of all mutati...