Hormone Replacement Therapy to Treat Turner Syndrome

This study will evaluate the effects of hormone replacement therapy on patients with Turner syndrome (TS)-a genetic disorder in females in which part or all of one X chromosome is missing. Most girls and women with TS have underdeveloped ovaries-the female reproductive organs that produce the female sex hormones estrogen and progesterone, and smaller amounts of the male sex hormone, testosterone. These hormones affect muscle and bone strength, sex drive, energy, and an overall sense of well being. Estrogen may also play a role in memory and mood and have a protective effect against heart disease. Women with TS have a much higher risk of developing osteoporosis (loss of bone density), high blood pressure, high cholesterol and diabetes than women without this disorder. Girls and women with Turner syndrome between the ages of 14 and 50 years may be eligible for this 2-year study. Three months before beginning treatment, all patients will wear an estrogen patch and take a progesterone tablet daily for 10 days each month. They will then be randomly assigned to one of two treatment groups to compare the effects of estrogen alone with estrogen plus testosterone on bone strength, muscle and fat mass and psychosocial well being. Both groups will wear an estrogen patch and take oral progesterone. One group will also wear a testosterone patch while the other group will wear a placebo patch (a patch that does not contain any testosterone). Neither study participants nor the doctors will know who is getting the testosterone until the study is complete. Patients will undergo the following procedures before beginning treatment and at 6, 12 and 24 months after starting treatment: * Physical examination. * DEXA scans (dual energy X-ray absorptiometry) to measure body composition and bone thickness. Low radiation X-rays scan the whole body to measure fat, muscle and bone mineral content.. * Magnetic resonance imaging (MRI) scan of the abdomen to measure the amount of fat around the