Genetics of Alzheimer Disease

Alzheimer disease (AD) is the most common cause of dementia, a progressive and irreversible impairment of cognitive function. Family aggregation studies, twin studies, and segregation analysis provide substantial evidence for genetic influences in this illness, and studies to find genes contributing to AD have successfully identified many candidates. Missense mutations of the APP , PSEN1 , and PSEN2 genes cause early-onset forms of AD (EOAD); however, persons with these autosomal dominant mutations constitute less than 2% of AD cases.