GENETIC SCREENING IN HEREDITARY MULTIPLE ENDOCRINE NEOPLASIA TYPE-1 -ABSENCE OF A FOUNDER EFFECT AMONG JAPANESE FAMILIES

Ten Japanese families with hereditary multiple endocrine neoplasia typ e 1 (MEN1) were examined. Five DNA polymorphic markers on the long arm of chromosome 11 were analyzed for genetic screening of MEN1 in membe rs of affected families, and disease carriers were identified before c linical manifestations, Unlike MEN1 families in Newfoundland or in Tas mania, no consistent haplotypes were segregated with the disease in th e Japanese families when defined by 5 nearby markers. The identificati on of asymptomatic disease carriers is of substantial clinical importa nce for early management, genetic counseling and to avoid unnecessary screening for non-disease carriers. However, genetic screening of fami ly members by polymorphic markers could be useful only to each family, and no generally applicable markers were found for Japanese subjects with MEN1.