Sickle-cell anemia

glutamic acid valine A A base—pair substitution results in the abnormal beta globin chain of sickle hemo— globin (HbS). The sixth amino acid in such chains is valine, not glutamic acid. The dif— ference causes HbS molecules to form rod— shaped clumps that distort normally round blood cells into sickle shapes. sickled cell normal cell B The sickled cells clog small blood vessels, causing circulatory problems that result in damage to many organs. Destruction of the cells by the body’s immune system results in anemia. Tionne “T—Boz" Watkins of the music group TLC is a celebrity spokesperson for the Sickle Cell Disease Association of America. She was diagnosed with sickle—cell anemia as a child.