Inherited Medullary Thyroid Carcinoma: A Final Monoclonal Mutation in One of Multiple Clones of Susceptible Cells

Abstract
Inherited medullary thyroid carcinomas contain one form of glucose-6-phosphate dehydrogenase (G6PD) in black female patients who are mosaic in normal tissues for G6PD types A and B. The same individual may have several tumors each containing either G6PD A or G6PD B. The data suggest that the inherited defect is an initial mutation producing multiple clones of defective cells; each tumor then arises as a final mutation in one clone of these cells.