Genetic basis for dyslexia traced

Scientists have identified the location of a gene for dyslexia, creating the possibility of screening and the early treatment of the disorder. An international team in Norway, Belgium and the US has narrowed the new gene's location to a short stretch of DNA on chromosome 2 by studying a large Norwegian family in whom dyslexia is common.

The researchers hope to sieve through the 100-odd genes in the stretch of DNA to identify the specific gene. That, says Dr Toril Fagerheim of University Hospital of Tromsoe, Norway, who led the research, 'will provide us with insight into the nature and frequency of at least one gene that is involved in reading and spelling'.

The work is reported in the Journal of Medical Genetics. Dyslexia is thought to affect between four and eight per cent of children. The idea of screening children for dyslexia is promising because the condition may be found early enough for treatment. Children under two who suffer problems with the language areas of the left side of the brain can go on to develop normal language ability, say the authors of the report. But other dyslexia researchers have pointed out that the disorder is caused by both genetic and environmental factors. Studies have shown that only 60 per cent of the variance in reading ability is explained by inheritance.