Dyslexia Gene Located - Strongest Evidence Yet for Genetic Link to Reading Disorder

3 January 2002

In the largest study of its type to date, researchers based at the Wellcome Trust Centre for Human Genetics in Oxford have identified a region of chromosome 18 that is linked to dyslexia, a reading disorder that affects 5-10 per cent of children worldwide.

A total of 208 families from the UK and Colorado, in which at least one child was dyslexic, were studied.

1

Making use of the publicly available Human Genome Project data, the researchers went on to confirm a link between the chromosome 18 region and dyslexia in an independent group of 84 UK families.

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Professor Tony Monaco, Director of the Wellcome Trust Centre for Human Genetics, said: “It is rare to find such a strong link between a genetic region and complex disorder. This is the first time the whole genome has been scanned in a large number of families with dyslexia from different parts of the world, which is why the results are so interesting.”

The researchers measured the severity of dyslexia in a large number of affected families, and how differences in the severity of the disorder correlated with its inheritance. All previous studies had either looked for a link between specific chromosome regions and dyslexia, or investigated a small number of specific families.

The research, which was carried out by Drs Simon Fisher and Clyde Francks at the Wellcome Trust Centre in Oxford, showed that the chromosome 18 region contains a general risk factor for dyslexia. The findings are to be published in the January issue of Nature Genetics.

Professor Monaco added: “So far we have only mapped the gene to a chromosome region, we have yet to find the gene and determine what it does. "Over the next few years, we will be looking at the genes most likely to be associated with the disorder. This is not the only region involved in dyslexia but it is the strongest evidence to date for a link between the disorder and a specific gene region.”

Professor Monaco, whose group recently identified a gene involved in the acquisition of speech and language, said that there may be up to 30 genes in this region of chromosome 18. In addition, the study confirmed previous findings that regions of chromosomes 2 and 6 are also involved in dyslexia.

Professor Monaco added: “Once we have identified the gene, that knowledge could play a role in early diagnosis. As the regions of the brain involved in language development are relatively plastic during early childhood, we are hopeful that interventions might minimise the effects of the disorder, but this could take many years to bear fruit.”

Footnotes:

1. Eighty-nine families from a clinic in Reading, Berkshire, were recruited by Professor John Stein, and 119 from Colorado recruited by Professor John DeFries and colleagues.

2. The chromosome region is known as 18p11.2.

Notes to Editors:
The web-site for the project, which also contains further information about dyslexia, is available at: www.well.ox.ac.uk/monaco/dyslexiasimon.shtml

Media contact:
Miriam De Lacy
Wellcome Trust Media Office
Tel: +44 (0)20 7611 8866
E-mail: m.delacy@wellcome.ac.uk, media.office@wellcome.ac.uk