Iatrogenic, Congenic, and Transgenic Models of Hypertension

Human essential hypertension is a multifactorial and complex disease involving several genes that have, thus far, defied complete characterization. Congenic models such as the spontaneously hypertensive stroke-prone rats are genetically homogeneous and thus aid the search for causative genes. The identification of quantitative trait loci (QTL) responsible for blood pressure regulation by genome-wide scanning is most commonly employed;1 however, the identification of a QTL is just the first step to identify the gene(s) of interest. Congenic strains must be produced to verify the QTL and identify the chromosomal region that must then be reduced to an appropriate size for positional cloning of the gene(s). So-called “speed congenic strategies” have been used to confirm blood pressure QTLs on rat chromosome 2.2