Scientists fix genetic defect in human cells

A team of scientists led by Professor Juan Carlos Izpisua Belmonte, from the Salk Institute in La Jolla, California has combined stem cell technology and gene therapy to fix a genetic mutation in human cells grown in the laboratory. The researchers, who published their achievement in Nature, hope that this technique could one day be used to treat a number of inherited conditions in humans.

The scientists took skin cells from six patients with Fanconi anaemia (FA), a rare genetic condition that is caused by mutations in any one of 13 different FA genes. FA can progress to bone marrow failure, leukaemia and other cancers. Current treatment relies on a bone marrow transplant from a perfectly matched donor, but patients remain at high risk of developing cancer.

Professor Belmonte's team produced iPS (induced pluripotent stem) cells, which are embryonic-like cells that have the potential to become any cell type, by re-programming the skin cells taken from the patient. They then fixed the mutation using a virus to insert a working copy of the gene into the iPS cells' genetic code. The resultant iPS cells can produce a limitless supply of healthy 'daughter' cells that could potentially be injected back into the patient to treat the disease. As the cells originate from the patient, this removes the risk of them being rejected.

Professor Belmonte told Genetic Engineering and Biotechnology News 'The hope in the field has always been that we'll be able to correct a disease genetically and then make iPS cells that differentiate into the type of tissue where the disease is manifested and bring it to the clinic'.

The use of a virus to integrate the corrected gene into the genetic code of the patient's cells could promote cancer and it is not known how safe this would be in humans. However, recently developed methods that do not use viruses could provide an alternative, if they are suitable for human cells. 'We haven't cured a human being, but we have cured a cell. In theory we could transplant it into a human and cure disease,' said Professor Belmonte.

The technology could be also be used to treat genetic diseases such as Parkinson's, motor neuron disease and diabetes. 'There is no doubt that this paper will be the first of many to offer hope for conditions where today there is no real therapy, yet alone a cure,' Professor Chris Mason, a stem cell scientist at University College London told the Nursing Times.