About five million Germans have serious learning difficulties when it comes to reading and writing. It is frequently the case that several members of the same family are affected. So hereditary disposition seems to play an important role in the occurrence of dyslexia.
Scientists at the universities of Marburg, Würzburg and Bonn have been working on this question together with Swedish colleagues from the Karolinska Institute in Stockholm. In examinations of German children with serious reading and writing difficulties they have now succeeded in demonstrating for the first time the contribution of a specific gene. Precisely how it contributes to the disorder remains unclear. It is thought that the genes may affect the migration of nerve cells in the brain as it evolves. The results will be published in the January edition of the American Journal of Human Genetics, but have already been made available online.
For several years child and youth psychologists at the universities of Marburg and Würzburg searched for families in which at least one child was considered dyslexic. "We then analysed blood samples taken from the families to identify candidate genes – and in the end we found the right one," explains the scientist who headed this part of the study from Marburg, Privatdozent Dr. Gerd Schulte-Körne.
The gene is located in the region of Chromosome 6, which had already been indicated by scientists from the USA and England in connection with reading and spelling disabilities. But the German-Swedish team has gone further and identified within this region a single gene which, as found among German children, is apparently an important factor in the emergence of dyslexia. "Known as the DCDC2 gene, it appears to affect the migration of nerve cells in the developing brain," says Professor Dr. Markus Nöthen from the Life and Brain Centre at Bonn University. Professor Nöthen and his team are in charge of the molecular work within the project.