"LCA is usually a disease where protein function has been lost completely, but carriers of just one copy of the mutation, who will almost certainly have reduced protein levels, nevertheless function perfectly normally," explains Professor Inglehearn. "This being the case, restoration of even a tenth of the missing protein may be enough to restore vision. So our findings, together with the recently announced clinical trials, hold great promise."
Mutations in LCA5 are relatively rare. As it is a recessive gene, a child would need to be carrying two copies of the gene to develop LCA, one from each parent. However, the disorder is more common within populations where marriage to first or second cousins is common, such as the Pakistani community.
"If a parent is found to carry a mutation in the LCA5 gene, the risk of blindness in their children and grandchildren is still virtually zero as long as the other parent does not carry it," says Professor Inglehearn. "The odds of two parents both carrying the same or different mutations in the LCA5 gene is very low, but this increases where the parents are related."
Professor Inglehearn hopes that the findings will be useful to inform and counsel the families most at risk, particularly within the Pakistani communities both in the UK and Northern Pakistan.
The findings have been welcomed by Bruce Noble from Yorkshire Eye Research, which part-funded the research.
"Obviously we have to be careful how we interpret these results, as finding the genes doesn't automatically lead to a cure," says Mr Noble. "Nevertheless, this new result tells us something very important about what the eye is doing normally and about a new and common way in which it can go wrong. Given some exciting recent developments on testing possible c