Clonal origin of inherited medullary thyroid carcinoma and pheochromocytoma

A black female with inherited medullary thyroid carcinoma and pheochromocytoma was a mosaic for glucose-6-phosphate dehydrogenase types A and B in normal tissues (blood, thyroid, and adrenal gland); both the medullary carcinoma and pheochromocytoma tissue showed a B pattern only. This finding suggests a single clone origin for each of the tumors. Other inherited tumors similarly studied in man have appeared to be multiclonal in origin.