In the present study, there was a progressive increase in systolic BP in both CsX male SD and CsX-Tfm rats; however, there was a delay in the onset of HT in the CsX-Tfm rats, followed by a more rapid increase in the HT which matched that of CsX-SD male rats by week 10, and a more rapid anti-hypertensive response to TES therapy. The gene discussed is NKX2-5; the disease is hematocrit.