Gene linked to handedness offers clue for dyslexia

Researchers from the Wellcome Trust Centre for Human Genetics at The University of Oxford have identified a genetic link between handedness and reading difficulties.The researchers performed a genome-wide association (GWAS) analysis for a quantitative measure of relative hand skill in individuals with dyslexia and identified a region on the PCSK6 gene as the most highly associated marker. Children with dyslexia who have a particular variant of the gene were on average more skilled with their right hand compared to the left than those without the variant. The same result was also found in two additional groups of children with reading difficulties.
Professor Anthony Monaco, lead author of the study, said the results support the idea that 'there is a link between handedness and language-related disorders'. The gene studied, known as PCSK6, has not been linked to handedness before but is known to be involved in other biological functions.
Previously several genes have been linked to dyslexia but the results published by Professor Monaco and his colleagues are the first to provide molecular evidence that the well-known asymmetry between the two brain hemispheres related to handedness and dyslexia are linked. Although handedness is a heritable trait, its genetic basis is not well understood.
PCSK6 is known to influence early embryonic development. The scientists believe its genetic variants might play a role during the initial left-right patterning of the developing embryo which affects brain asymmetry and therefore handedness. Future functional studies of PCSK6 might reveal mechanisms underlying lateralisation within the brain and dyslexia. The findings were published in the journal Human Molecular Genetics.