False-colored scanning electron micrograph of erythrocytes n9 H8 l7 W, H
(diameter ~7 micrometers). Sickle cell disease results from an 6 Z/ z" F8 O; o7 Y- linherited defect of adult hemoglobin, the oxygen-carrying9 z' C: V7 m$ y$ ?
metalloprotein constituent of erythrocytes. Common genetic variation1 N9 b3 ^* z) h3 O3 B; l$ w2 q8 G
associated with sickle cell disease severity modulates an adult-stage- ~( `4 {" f T+ U
erythroid enhancer element of the BCL11A gene. Disruption of this % a! k* r. |# Y D6 r* eelement could ameliorate the disease by reestablishing expression * w a( v0 W P! Q5 A: wof fetal hemoglobin. See pages 206 and 253.2 h; @2 w# N( ~" R- T