Yet more genetic clues to dyslexia discovered

A year after scientists discovered a gene whose flaw contributes to dyslexia, scientists have identified two more such genes.

The findings strongly support the idea that many people deemed lazy or stupid because of severe reading problems may have a genetic disorder that interfered with the connections in their brains before birth.

Dr Albert Galaburda of the Harvard Medical School, an authority on developmental disorders who was not involved in the latest discoveries, said the combined findings meant that, for the first time, „we have a link between genes, brain development and a complex behavioural syndrome“.

A genetic test for dyslexia should be available within a year or less, researchers into the condition said. Children in families that have a history of the disorder could be tested before they started learning to read. If children were carrying a genetic risk of dyslexia they could be put in early intervention programs.

One of the genes newly linked to dyslexia is called DCDC2. It was active in reading centres in the human brain, said Dr Jeffrey Gruen, a Yale geneticist who announced the discovery.

The second gene, called Robo1, was discovered by Dr Juha Kere, a professor of molecular genetics at the Karolinska Institute in Stockholm. It is a developmental gene that guides connections, called axons, between the brain’s two hemispheres. When the gene’s activity is reduced, there are fewer finer connections in the area of the brain used for reading.

„You get the right signals going, but they do less well in terms of rapid processing,“ Dr Kere said.

Many dyslexia experts believe that reading problems arise from an inability to process the fast sounds of spoken words.

The New York Times