The team worked on embryonic stem cells carrying the human sickle cell mutation. They inserted a healthy copy of the haemoglobin gene, which then replaced the mutated version.

This inserted gene then generated stem cells which carried the sickle cell trait, but not sickle shaped cells.

Individuals with sickle cell trait are generally healthy.

The researchers eventually hope to be able to genetically alter human embryonic stem cells from a patient's own DNA and transplant them back into the patient, correcting their sickle cell anaemia.

They said that in theory the same stem cell gene therapy could be used to cure another genetic blood disorder, thalassaemia.

Read More at the BBC - Stem cells treat sickle cell anemia