Childhood-Onset Essential Hypertension Natural History Study

Background: Childhood-onset essential hypertension (COEH) is high blood pressure that develops in children and teens. High blood pressure is a major risk factor for heart disease. COEH is more likely to be caused by changes in genes rather than by factors like stress or diet. Researchers want to learn more about how changes in genes relate to COEH. They hope to use that information to develop better treatments for children with high blood pressure. Objective: This natural history study will look for genes and gene changes that may lead to COEH. Eligibility: People aged 2 years and older with COEH or who had COEH when they were children. Healthy relatives of those with COEH are also needed. Design: Participants will have one clinic visit per year for up to 10 years. All participants will have a physical exam. They will provide samples of blood and urine. At their first visit, they will have a swab (like a Q-tip) rubbed between their gums and cheeks. They may agree to having a skin biopsy; a piece of skin about the size of a pencil eraser will be removed. Affected participants aged 2 to 17 years old will have additional tests: * They will have sensors placed on their skin to look at their blood vessels and see how blood is moving in their bodies. * They will lie or stand while a machine measures the amount of fat and muscle in their bodies. * They will have an ultrasound; a wand will be rubbed against their skin to take pictures of their kidneys. Other things are optional for all participants: * They may have photographs taken of their bodies. * They may have tests of their heart function. * They may have different types of imaging scans.