title: Sickle-cell anemia: the known and the unknown.
mesh_terms: D000349:Africa; D000368:Aged; D000755:Anemia, Sickle Cell / Q000453:epidemiology / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D006306:Health Surveys; D006801:Humans; D008017:Life Expectancy; D008875:Middle Aged; D014481:United States