Sickle cell disease is a group of blood disorders, the most common is the sickle cell anemia. It is a genetic mutation of the oxygen-carrying protein hemoglobin found in red blood cells. This leads to a rigid, sickle-like shape. This hemoglobin (HbS) is a variant of normal human hemoglobin (HbA). From a molecular point of view, the mutation induces polymerization of HbS, when the protein is in its deoxygenated state and very concentrated. Recently, the Henri-Mondor hospital developed a genetic cure for sickle cell anemia and successfully cured a first patient. After 15 months, a mixture of HbS and HbA composes the total amount of patient hemoglobin and no sickle cell anemia crises are observed. In this experiment, we want to characterise using SANS the structure of HbS and of the mixture of HbS and therapeutic HbA to verify at which concentration the polymerization is not taking place and, more important, to compare the structure of cured patient with the one of a sane patient. This is a crucial step in the understanding of the genetic cure. Different oxygen partial pressure will be investigated to simulate different body environment (lungs, heart, tissues).