Genetic and clinical characteristics of multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN 1) is an inherited disorder of autosomal-dominant type encompassing tumors of the parathyroid glands, anterior pituitary and endocrine pancreas. The genetic defect responsible for MEN 1 maps to the long arm of chromosome 11 (11q13). Constitutional heterozygosity for the MEN 1 region is lost in proliferating pancreatic endocrine and parathyroid tissue, which suggests that the MEN 1 gene belongs to the group of tumor suppressor genes (antioncogenes). Genetic screening by linkage analysis using RFLP markers allows selection of gene carriers with high degree of accuracy and makes it possible to concentrate the laborious biochemical screening efforts to family members at risk of developing the MEN 1 syndrome. Biochemical screening of the MEN 1 lesions in young asymptomatic individuals decreases the age at diagnosis with many years (decades) and therapeutic intervention can be instituted early. Although it still remains to be established whether early intervention will have an impact on mortality, our long-term experience with 20 MEN 1 kindreds suggests a reduced morbidity as a result of thorough biochemical screening.