The first genome-scale study looking for the genes that contribute to dyslexia has made a breakthrough that could lead to early diagnosis of this childhood learning difficulty.
Simon Fisher and colleagues at the Wellcome Trust Centre for Human Genetics in Oxford have identified three hotspots where the genes responsible are likely to be located.
Between 5 and 10 per cent of children are affected by dyslexia, defined as a reading disorder that cannot be accounted for through lack of opportunity, intelligence or motivation.
Studies of twins showed that a child's genetic make-up can have a strong influence on developing dyslexia.
The team analysed DNA from 208 British and American families with dyslexic children, collected in collaboration with research groups in Oxford and Colorado. They found that a previously overlooked region on chromosome 18 was linked to the condition and confirmed findings that linked regions on chromosomes two and six.
The group is examining the regions in more detail to identify individual genes that contribute to dyslexia.
The team's results are published in the journal Nature Genetics .