A five-country research team identified one of the causes of an eye disease known as Leber congenital amaurosis, one of the most common causes of inherited blindness in children.

The research team was led by the Casey Eye Institute Molecular Diagnostic Laboratory, the Beijing Genomics Institute and the No 1 Affiliated Hospital of the School of Medicine of Zhejiang University.

The study with the findings was published online in scientific journal Nature Genetics, reporting the genetic characteristics of some patients, and providing important evidence that support that mutations in a gene, known as NMNAT1, are a promising target for gene therapy.

LCA is an inherited retinal degenerative disease characterized by severe loss of vision at birth. It is estimated to occur in two to three out of 100,000 newborns.

Currently several studies are being done on the disease. Scientists found that it could result from mutations in at least 17 genes, all of which are necessary for normal vision and play important roles in the development and function of the retina.

More importantly, gene replacement therapy has been successful in animal models and in humans more studies are under way. However, the genetic characters for about 20 to 30 percent of the patients are still unknown.

In this study, the researchers sequenced the whole exome of an LCA patient with no previously identified mutations. They identified 2,460 previously unreported variants.

Qi Ming, chief scientist with the Beijing Genomics Institute, said that the study lays a solid foundation for understanding genetic characteristics of the disease and other related congenital blindness diseases and is an important step forward for developing new molecular diagnosis and gene therapy.