Increased aneuploidy in Alzheimer disease.

The purpose of this study was to determine if cytogenetic changes are present in Alzheimer disease, one of the presenile dementias. The chromosomes of three groups of people were studied: 1) sporadic cases of Alzheimer disease (eight cases), 2) familial cases of Alzheimer disease with affected individuals in at least two generations of their families (five cases), and 3) currently unaffected siblings of the affected individuals in these families (nine cases). One hundred cells per individual were examined using GTG banding to allow chromosome identification. A statistically significant increase in aneuploidy was found in five of eight patients in group 1 (P less than 0.05) and in each of five patients in group 2 (P less than 0.001) when compared with the rate of aneuploidy in age- and sex-matched controls. In addition, two individuals in group 3 exhibited a significant increase in aneuploidy over the control group, raising the possibility that finding increased aneuploidy may allow one to anticipate the clinical expression of the disease state.