My research interests are in the genetic analysis of disease. Historically, we have worked on the genetic analysis of Alzheimer's disease and other dementias. More recently, we have worked on Parkinson's disease and other movement disorders and, most recently on motor neuron disease. Our early studies were on mendelian forms of disease and these studies continue, but an increasing focus has been on the genetic analysis of complex traits related to disease. Additionally, this latter analysis has made us increasingly interested in population genetics because the risk variants for human traits are likely to be different in different racial groups.