Test Details: Medullary Thyroid Carcinoma (MTC) of the thyroid constitutes 5-10% of all thyroid carcinomas, arising from the C cells of the thyroid, of neural crest origin. Germ-line activating point mutation in the RET proto-oncogene are associated with the pathogenesis of familial MTC. Since this disorder can be genetically inherited, family member of a patient with mutation in RET proto-oncogene can be tested for that particular exon.