Traço falciforme: heterozigose para hemoglobina S

Hemoglobin S (HbS) is one of the most common hereditary hematological alterations. In Brazil, the frequency of the sickle cell trait (HbAS) varies from 2% to 8%. Thus, there is an estimate of more than two million carriers of the HbAS sickle cell trait in Brazil. Different to homozygous carriers for Hb S (Hb SS), individuals with the sickle cell trait do not present with vaso-occlusive symptoms under physiologic conditions. Some clinical signals associated to the sickle cell trait only occur under conditions that favor the sickling process, including hypoxia, acidosis and dehydration. Life expectancy is similar to the general population. Hence, the condition of asymptomatic carrier should not affect the style and quality of life.