Genetics of Dementia

Recognition that genes play an important role in determining risk for Alzheimer’s disease (AD) in the majority of cases is a recent phenomenon and is the direct result of molecular genetic studies during the last two decades. We now know that AD is a complex disease with multiple causes, although the underlying mechanism may be similar in all cases. Early-onset familial AD (FAD) is linked to specific rare, highly penetrant mutations (1). In contrast, risk for late-onset AD is likely the result of a combination of genetic and environmental risk factors. Interactions between AD genes and the environment are still poorly defined. However, studies from the past 10-15 years have given many insights into genes that play a role in AD and have produced models of the underlying molecular interactions that lead to disease.