Absence of linkage disequilibrium at amyloid precursor protein gene locus in Japanese familia Alzheimer's disease with 717Val→Ile mutation

Abstract To date, eleven independent FAD pedigrees with the 717 Val→Ile mutation have been identified. Interestingly, five pedigrees were of Japanese origin and four were of British origin. The apparent ethnic prediction of this mutation raises the possibility that there is a founder effect in these two island nations. We did not observe any significant linkage disequilibrium in any locus of APP and GT12 loci in the five Japanese FAD pedigrees with the 717 Val→Ile mutation. A founder effect would probably not be present in Japanese FAD pedgrees with the 717 Val→Ile mutation.