| Hemoglobin S
An abnormal Hb with substitution of a valyl residue for a glutamyl residue at the sixth position of the ß chain; the formula is a2Aß2S, or, more specifically, a2Aß26Glu?Val. Heterozygous state: sickle cell trait, no anemia, Hb S 20–45% of total, the rest Hb A. Homozygous state: sickle cell anemia, Hb S 75–100% of total, the rest Hb F or Hb A2. | |