Scientists have identified alterations in 10 genes that significantly contribute to nearly 10 percent of all childhood blindness.

Of the 10 genes, three were linked to the activity of one molecule -- known as actin -- among patients with a disease known as ocular coloboma, which causes part of the eye to be missing at birth.Ocular coloboma can cause a distinctive keyhole-shaped pupil as it commonly results in a missing segment in the iris, the coloured part of the eye."Coloboma can have profound effects on visual ability, but it is very variable and therefore likely to be caused by a number of genes. Our work adds knowledge to our understanding of its onset as well as the importance of actin to eye development," said Joe Rainger from the University of Edinburgh.

Actin is important to a number of vital cell functions, including maintenance of the cytoskeleton, which defines cell shape and structure.Targeted gene sequencing showed that one of the mutations -- a specific alteration in the gene ACTG1 -- recurred across a number of those tested, the researchers said, in the paper published in the journal Human Mutation.The scientists edited this ACTG1 mutation into a line of mice using cutting-edge CRISPR/Cas9 gene-editing technology, and found that it had severe effects on the function of actin.

Further, these mutations were thought to affect how actin binds to other proteins and on actin stability, which could severely affect development of the eye in the womb, scientists explained.For the study, the team worked with 12 families, studying the DNA of children with coloboma and their unaffected parents.