The Framingham Study: Examining DNA Markers and Links to Diseases

Many studies have shown that hematocrit (HCT) levels are associated with cerebrovascular disease, cardiovascular disease (CVD), peripheral vascular disease, as well as all-cause mortality. Twin studies have shown that HCT variation is largely determined by genetic factors with heritability estimated as 40% - 65%. So far, no linkage analysis in humans between HCT and DNA markers have been reported. The purpose of this protocol is to identify chromosome regions that contain quantitative trait loci (QTL) involved in controlling HCT levels. In the Framingham Study, a 10cM genome scan (about 400 markers) has been conducted in 330 families. HCT was measured in the original cohort and Framingham offspring. These data provide us the opportunity to undertake linkage analyses using variance component method to map quantitative trait loci (QTL) of HCT.