Progression Evaluation and Genetic Determinants of Hypertension in Chinese - A Follow-up Study of Taiwan SAPPHIRe

Blood pressure is a quantitative trait affected by both genetic and environmental factors. It is known that human essential hypertension does not follow a simple Mendelian mode of inheritance. Stanford-Asian Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe) is an international genetic study, which intends to map the major genetic loci underlying hypertension in sibpairs of Asian-Pacific Chinese and Japanese origin. Based on the data generated through year 1 to year 5, preliminary analysis has not shown positive results in the linkage analysis of genome wide scan data, although association studies of some candidate genes give promising results. Success in genetic studies may depend on many factors including the selection of the patient population, the identification of intermediate phenotypes, the disease subsets, and the genetic strategy and methodologies employed. According to our previous analysis, presented in SAPPHIRe Steering Committee meetings (twice a year), there is heterogeneity among Chinese and Japanese origins. In order to reduce heterogeneity of the genetic and environmental background, we will focus our investigation on the Chinese population. Furthermore, besides the variables associated with insulin resistance, which were collected and studied in year 1 through 5 of SAPPHIRe, some more variables will be collected and studied in order to identify most sensible intermediate phenotypes and more homogeneous disease subsets. Our general approach is to continue analyzing candidate genes as well as perform a complete genome search based on the exiting genome-wide scan data together with old and new phenotype variables.