Evaluation of Non-invasive Endothelial Function in Children Sickle by Vascular Ultrasound

Inclusion Criteria: Sickle cell group : * Children with sickle cell syndrome (SS or SC) * Children hospitalized in the hematology unit (day hospital) * The girls set must have had a negative pregnancy test. * One of the two holders of parental authority must have signed consent form * Children affiliated to a social security scheme or equivalent Control group : Children recruited in a previous study : * Holders of parental authority affiliated to a social security scheme * Children recruited during the balance of a heart murmur or a vasovagal reaction * Children whose cardiological examination is normal * Children having no cardiovascular risk factor Exclusion Criteria: Sickle cell group : * Children with intercurrent diseases such as obesity, intra uterine growth retardation (IUGR), hypertension, renal failure, infectious diseases (including HIV, Hepatitis C) or chronic inflammatory * Children who have sickle cell crisis there is less than 1 month. Control group : Children with intercurrent diseases: obesity, IUGR, hypertension, renal failure, infectious diseases (including HIV, Hepatitis C) or chronic inflammatory