Family data on traits related to hypertension on over 300 individuals have been collected by Drs. O'Connor and Parmer at UCSD. The objective of the project is to investigate the variation in traits related to aspects of the sympatheic neuroeffector juction and ultimately in changes in blood pressure and hypertension, and to attempt to determine whether genetic components are responsible, at least in part, for this variation. Computer simulation studies have been done to determine the power of the sample to detect linkage. Genotyping for the project has been approved by the Center for Inherited Disease Research Access Committee. The collection of additional phenotyping information is conditional on obtaining additional NIH funding.