Gene probe analysis in an informative family with multiple endocrine neoplasia syndrome type 2A (MEN 2A). Improvement in carrier risk estimation.

Gene probe analysis of the MEN 2A locus on chromosome 10 has been undertaken using the markers TB10.163, RBP 3 and TB14.34 in a large kindred with familial medullary thyroid carcinomas, with or without phaeochromocytomas or primary hyperparathyroidism. A maximum LOD score of 2.97 gave strong evidence of close linkage with zero recombination. For 12 members of the family so far not known to be affected by any form of the disease the estimated risk of carrying the gene has been considerably decreased in all but one, whose risk has been greatly increased.