Germline Mutations of the MEN1 Gene in Japanese Kindred with Multiple Endocrine Neoplasia Type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome. The responsible gene MEN1 has recently been isolated, and its germline mutations have been identified in affected individuals in the United States, Canada and Europe. We screened for MEN1 mutations by direct nucleotide sequencing of all protein-coding regions, and identified five distinct germline mutations in five among six Japanese kindreds with familial MEN1 or familial hyperparathyroidism. The mutations were dispersed across the gene. These findings suggest that, because of the absence of an obvious founder effect, the entire MEN1 gene region should be examined for germline mutations in the probands of MEN1 and related syndromes in Japanese families.