By knocking out a single gene, researchers have reversed sickle-cell disease in mice.
This genetic disorder results from a mutation in the adult form of the oxygen-carrying haemoglobin protein found in red blood cells, making the cells defective and causing anaemia. The fetal form is not mutated, however, so Stuart Orkin at the Dana Farber/Children's Hospital Cancer Center in Boston, Massachusetts, and his colleagues tested the effect of deleting the gene Bcl11a, which suppresses the expression of fetal haemoglobin in adults, in a mouse model of the disease.
Knockout animals had haemoglobin and red-blood-cell levels close to those of normal mice. Red blood cells from the knockout animals (pictured, right panel) resembled those of normal controls (left) rather than those of sick mice (centre). The authors say that the BCL11A protein could be a potential, although challenging, drug target.