Predisposition Genetic Testing for Late-Onset Disorders in Adults

Abstract
RAPID ADVANCES, such as those related to the Human Genome Project, have dramatically increased the number of available molecular genetic tests, and this number will only increase with future genetics research. Until recently, most such tests have been for rare monogenic conditions. Many of these single-gene disorders show signs or symptoms during childhood, while some, such as Huntington disease and adultonset polycystic kidney disease, have later onset. Molecular genetic tests have now become available for more common, complex conditions with onset later in life. Identification of cancer susceptibility genes1-6and of genes leading to several neurogenetic disorders, including Alzheimer disease7and some forms of ataxia,8represents the start of a cascade of genes to be identified that confer susceptibility to adult-onset diseases. Understanding of the genetic basis for other complex diseases, such as diabetes, heart disease, and psychiatric disorders, is advancing at a rapid pace.9-11These