Whether in the childhood stage or in the adult stage, Turner syndrome should be seen by a cardiologist. Turner syndrome is also known as congenital ovarian hypoplasia. Humans have 23 pairs of 46 chromosomes, one of which is a sex chromosome. The sex chromosomes for boys are the X chromosome and the Y chromosome, and both sex chromosomes for girls are the X chromosome. If a girl has only one X chromosome, or if part of the X chromosome (including the top part of its short arm) is lost, Turner syndrome can occur. Because the X chromosome contains many genes (about 1,000), the loss of the X chromosome can lead to many problems or even serious problems, with 99% of Turner syndrome fetuses aborted in utero and only 1% of fetuses viable and born. Cardiovascular disease is one of the serious problems. Epidemiological studies have shown that the mortality rate in Turner’s syndrome is three times higher than in the normal population, with circulatory diseases accounting for 41% of the mortality rate (11% ischemic heart disease, 11% cerebrovascular disease, 8% aortic aneurysm and 8% congenital heart disease). The mortality rate in young and middle-aged people with Turner’s syndrome is 4-5 times higher than in the normal population, and it is mainly due to complications of congenital heart disease and coronary artery disease in premature infants. Cardiac anomalies are also often a contraindication to assisted conception. What circulatory disorders are children and adults with Turner syndrome susceptible to? Congenital heart disease: Approximately 75% of fetuses and 25C45% of girls born alive with Turner syndrome have congenital heart disease. The most common anomalies are bilobed aortic valves (16%) and aortic constriction (11%); however, structural defects such as partial paradoxical pulmonary venous return and atrial and ventricular septal defects are also seen. In the diagnosis of Turner syndrome, imaging should then be considered in every patient, and in young girls, a transthoracic echocardiogram is sufficient if a clear image of the cardiac anatomy is available. Otherwise, or if there are other indications, cardiac MRI is recommended, with sedation if necessary. Adolescents and adults should have an MRI. Girls who have already been imaged in utero should be reviewed after birth. Aortic coarctation: A fatal event that occurs in 1C2% of the Turner’s syndrome population with preexisting lesions that are usually dilated in the aortic root and/or ascending aorta. Coarctation occurs relatively early with a median age of 35 years. Magnetic resonance can detect, but echocardiography cannot visualize, abnormal aortic arch elongation, right subclavian artery malformation, and partial ectopic pulmonary venous return syndrome. Therefore, longitudinal imaging every 5C10 years is recommended to assess changes in aortic diameter, even in those patients whose first cardiac examination is normal. Patients should be encouraged to carry a medical alert card and to request aortic coarctation evaluation when there is a sharp episode of chest pain. Therefore, an ECG should be done along with imaging. Hypertension: A major risk factor for cardiovascular events is hypertension, which affects 25% of adolescents and 40C60% of adults with Turner syndrome. Estradiol deficiency affects conditions related to glucose homeostasis, and early studies have reported changes in glucose homeostasis and the development of diabetes mellitus or impaired glucose tolerance in patients with Turner syndrome. Decreased glucose tolerance has been found in both girls and adult women with Turner syndrome, and the incidence of type 2 diabetes mellitus is four times higher in patients with Turner syndrome than in the normal population (relative risk: 4.4). Women with Turner syndrome are highly susceptible to the comorbidity of specific idiosyncratic autoimmune diseases, including type 1 diabetes. These are associated with endothelial cell dysfunction, reduced insulin production, abnormal fat metabolism, exacerbated centripetal obesity, and early onset of atherosclerosis. Therefore, blood pressure should be measured at every visit, and ambulatory blood pressure monitoring should be performed when necessary for a more accurate diagnosis of hypertension and assessment of its efficacy.