Gene therapy allows a French teen to dodge sickle-cell disease

A French teen who was given gene therapy for sickle- cell disease more than two years ago has enough properly working red blood cells to dodge the effects of the disorder, researchers report.

The first-in-the-world case is detailed in Thursday's New England Journal of Medicine.

About 90,000 people in the U.S., mostly black, have sickle cell, the first disease for which a molecular cause was found. Worldwide, about 275,000 babies are born with it each year.

"Vexing questions of race and stigma have shadowed the history of its medical treatment," including a time when blacks who carry the bad gene were urged not to have children, spurring accusations of genocide, Keith Wailoo of Princeton University wrote in a separate article in the journal.

The disease is caused by a single typo in the DNA alphabet of the gene for hemoglobin, the stuff in red blood cells that carries oxygen. When it's defective, the cells sickle into a crescent shape, clogging tiny blood vessels and causing bouts of extreme pain and sometimes more serious problems such as strokes and organ damage. It keeps many people from playing sports and enjoying other activities of normal life.

A stem-cell transplant from a blood-matched sibling is a potential cure, but in the U.S., fewer than one in five people have a donor like that.

Pain crises are treated with blood transfusions and drugs, but they're a temporary fix.

Gene therapy offers hope of a lasting one.

The boy, now 15, was treated at Necker Children's Hospital in Paris in October 2014.

Researchers gave him a gene, taken up by his blood stem cells, to help prevent the sickling.

Now, about half his red blood cells have normal hemoglobin; he has not needed a transfusion since three months after his treatment and is off all medicines.