Identification of the MEN1 gene as a disease gene for multiple endocrine ne
oplasia type 1 (MEN1) has made it possible to predict whether a family memb
er of an MEN1 patient will suffer from the same disease. MEN1 mutations hav
e been found in almost all cases with familial MEN1, but in fewer cases wit
h sporadic MEN1. We analyzed MEN1 mutations in the largest number of Japane
se MEN1 patients, 17 families and 21 sporadic cases, and found 54 MEN1 muta
nt carriers and 30 non-carriers. Furthermore, we identified a MEN1 phenocop
y: GH-secreting pituitary tumor and primary hyperparathyroidism, which deve
lops at older ages. In this article, we discuss how to utilize MEN1 gene di
agnostics for the clinical management of MEN1 patients and MEN1 mutation ca
rriers. (C) 2000 Editions scientifiques et medicales Elsevier SAS.