Huntington's Disease (HD) is a progressive, neurodegenerative disorder inherited in an autosomal dominant mode. Clinical symptoms are generally not manifested until the third to fifth decade of life. The goal of this project is to develop a genetic linkage test for the presymptomatic and prenatal diagnosis of HD. Phase II will consist of a field trial for the presymptomatic testing of individuals at-risk for HD using genetic linkage analysis. Individuals at-risk for HD will be evaluated for inclusion in the study, and appropriate families haplotyped for the HD-linked markers. Procedures developed in Phase I to manage the logistics of serving as a central reference laboratory serving a number of institutions will be evaluated in Phase II, as will protocols addressing other critical elements associated with the administration of a genetic linkage addressing other critical elements associated with the administration of a genetic linkage test for HD (psychosocial counseling, institutional approval etc.).
