Inactivation of the tumor suppressor gene on 11q13 in brothers with familial acrogigantism without multiple endocrine neoplasia type 1

Two of three brothers (the second and third brothers) and their uncle (their mother's brother) presented acrogigantism without multiple endocrine neoplasia type 1 (MEN 1). An invasive macroadenoma was found in the second brother, and it was histologically confirmed as a sparsely granulated GH cell adenoma. Two distinct microadenomas were found in the third brother, and these were histologically diagnosed as a mixed GH cell and PRL cell adenoma and a sparsely granulated GH cell adenoma, respectively. The loss of heterozygosity (LOH) was analyzed in two adenomas (GH cell adenoma from the second brother and a mixed GH cell and PRL cell adenoma from the third brother) by determining microsatellite polymorphisms of DNAs from tumors and patients' leukocytes. The LOH was found on the chromosome 11q13, whereas LOH was not detected on 1p31-36, 2p, 3p, 4, 5, 6p, 7, 8, 9p21-22, 12p, and 19q13 in both pituitary adenomas examined. The haplotype analysis showed that the same haplotype on 11q13 was found in their mother and the unaffected first brother as well as in the affected uncle and two brothers. The deleted alleles on chromosome 11q13 in the tumors of two affected brothers were, however, restricted to those transmitted from their unaffected father. These data suggest that inactivation of the MEN 1 gene or other tumor suppressor genes on chromosome 11q13 plays an important role for the development of our familial acrogigantism without MEN 1.