A little girl in Boston, for instance, inherited the sickle-cell disease gene mutation from both her parents, but is healthy. And that's because she has another mutation that is protecting her — her levels of fetal hemoglobin have remained high, according to Scientific American. That way, the fetal hemoglobin makes up for the deformed adult hemoglobin that bind each other, cause damage to cells, and lead to anemia.
Using tools like gene editing, companies are hoping to use these sorts of protective mutations to treat patients. For instance, Sangamo BioSciences and Biogen are exploring the use of zinc finger nucleases to disable the gene that typically regulates the shut-off of fetal hemoglobin production. Novartis is likewise pursuing that using a CRISPR-Cas9 approach.
"Gene-editing approaches have the potential to be game changing and really revolutionize the therapy," Novartis's Lloyd Klickstein tells Scientific American.
Other companies likes Bluebird Bio are investigating whether protective genes themselves can be added or, like Global Blood Therapeutics, whether the overly enthusiastic binding of hemoglobin that leads to sickle cell crises can be prevented.
But David Nathan, president emeritus of the Dana-Farber Cancer Institute, notes these treatments will likely only help those in the developed world with sickle cell. "It's the undeveloped world that has the burden [of this disease]," he adds.