Linkage and chromosome study of multiple endocrine neoplasia IIa

A linkage and chromosome investigation of a large family with multiple endocrine neoplasia (MEN) IIa (medullary thyroid carcinoma, pheochromocytoma, and occasionally hyperparathyroidism) was undertaken. No significantly positive lodscores were obtained between MEN IIa and 25 different genetic markers. Conventional metaphase chromosome analysis showed normal karyotypes and no heterochromatin markers linked to the MEN IIa locus were found. High-resolution chromosome analysis in five MEN IIa carriers revealed no deletion within band 20p12.2. The present investigation could thus neither demonstrate linkage of the MEN IIa locus to genetic or chromosome markers nor identify chromosome abnormalities in MEN IIa carriers.