Scientists edit genome to cure sickle cell anemia

Researchers have proven that a new gene editing technique could pave the way towards a cure for sickle cell disease. The disease affects about 5 million people globally. About 75 percent of cases occur in Africa where at least 200,000 children are born with the disease every year.

BERKELEY, CALIFORNIA, UNITED STATES (REUTERS) – Using a gene editing technique called CRISPR-Cas9, researchers have corrected a genetic mutation that causes sickle cell disease, paving the way towards a potential cure.

“We know exactly the mutation that causes the disease and we know that if we correct that mutation we will cure the disease,” Mark Dewitt of the University of California, Berkeley told Reuters.

Sickle cell disease is a painful genetic blood disorder that causes red blood cells to be abnormally crescent-shaped. These cells get stuck in blood vessels, blocking blood flow which leads to severe pain and organ damage.

The scientists focused their efforts on genetically flawed bone marrow stems cells that produce the abnormally shaped cells.

Sickle-cell anaemia affects millions of people worldwide. About 75 percent of cases are found in Africa and most commonly among people of West African descent.

Experts say many children in Africa born with the condition hardly get any screening done and treatment is often delayed.

Parents are being encouraged to take their children for testing and also get tested themselves to find out whether they carry sickle cell genes that could be passed on to their children.

Researchers say they have been able to correct the genetic mutation using stem cell samples from people with sickle cell disease – they used CRISPR-Cas9 to edit out the mutation in the stem cells genome and replace it with a corrected version. They then implanted these edited cells into a mouse.

“We grafted the cells in the mouse for four months and after four months we took them out and we looked at the levels of editing and we were getting levels of editing consistent with achieving a clinical benefit for patients with sickle cell disease,” said Dewitt. He added that the corrected stem cells produced healthy red blood cells efficiently enough to potentially cure the disease in human patients.

It will be some years before this research translates into treatment. The researchers need to scale up the process significantly, as well as prove its safety in humans.

The ability to edit genes is new science and the researchers need to prove that their efforts to cure one disease don’t lead to others in the process. But if proven harmless, gene editing could well be the answer to eliminating a host of genetic disorders in the years to come.

The findings were published last month in the online journal Science Translational Medicine.