Scientists use new gene therapy to treat hereditary blindness1 min read . Updated: 16 Jan 2014, 07:08 PM IST
The therapy is aimed to deliver the CHM gene into the cells of the retina, so that it starts to produce protein and stop the cells from dying off
New Delhi: Scientists in England have used gene therapy to treat patients with choroideremia (CHM) in a multi-centre clinical trial, according to a study published in Lancet on Wednesday.
Choroideremia is a hereditary disease that leads to blindness because of mutations in the CHM gene, leading to pigment cells in the retina of the eye to stop working and eventually die. Six months after the treatment, six of the patients showed improved perception of light in the eye, with two of the patients at advanced stages of choroidermia reading 21 letters instead of 11 letters on the eye chart.
The initial results of this retinal gene therapy trial reiterated that the virus can deliver its DNA load without causing significant damage to the retina. “These findings lend support to further assessment of gene therapy in the treatment of choroideremia and other diseases, such as age-related macular degeneration, for which interventions should ideally be applied before the onset of retinal thinning," the study concluded.
The gene therapy approach, developed by a team led by Robert Maclaren of the Nuffield Laboratory of Ophthalmology, carried out an operation in which the retina was detached and then a small virus was injected underneath the retina using a fine needle. The virus was used to deliver the missing CHM gene into the light-sensing cells called photoreceptors in the retina.
‘It is still too early to know if the gene therapy treatment will last indefinitely, but we can say that the vision improvements have been maintained for as long as we have been following up the patients, which is two years in one case," said Maclaren, author of the Lancet study. Maclaren said that as this was the first time that gene therapy was applied safely before the onset of vision loss, it had huge implications for anyone with a genetic retinal disease such as age-related macular degeneration or retinitis pigmentosa.
The therapy is aimed to deliver the CHM gene into the cells of the retina, so that it starts to produce protein and stop the cells from dying off.
“The results suggest that the approach has promise for treating people early on before too many cells in the retina have been lost," the Nuffield Laboratory of Ophthalmology said in a press statement on Thursday.