For the first time, researchers have identified a large number of genes that are reliably linked to dyslexia.
Approximately one-third of the 42 discovered genetic variations have previously been associated with general cognitive ability and educational achievement.
The observations, which were published in the journal Nature Genetics, are said to assist in comprehending the genetics underlying why certain children struggle to read or spell.
Dyslexia is well-known to run in families, partly due to genetic factors, but until today, very little is understood about the particular genes associated with the likelihood of developing it.
The University of Edinburgh is leading the largest genetic research on dyslexia to date. Earlier research relating dyslexia to specific genes was conducted on a small number of families, and the data was inconclusive, according to the research team.
This most recent study included over 50,000 persons who had been diagnosed with dyslexia and over one million adults who had not.
Researchers looked into the link between millions of genetic variants and dyslexia status and discovered 42 relevant variants.
Some of them are linked to other neurodevelopmental problems, such as language delay, as well as cognitive abilities, and academic achievement. Many, on the other hand, are novel and may reflect genes that are especially associated with processes required for learning to read.
Several of the genes related to dyslexia have also been linked to attention deficit hyperactivity disorder. For psychiatric, lifestyle, and health issues, there was substantially less overlap among the genes related to dyslexia.
Several of the related genetic variants were also substantial in a Chinese speaking group, indicating that there are general cognitive mechanisms in learning to read that are not language dependent.
Utilizing genetic information from the investigation, researchers claim they were able to anticipate how well children and adults from four other research studies could read and spell, but not with the accuracy required for diagnostic use.
Other major contributors to the research were from the Netherlands’ Max Planck Institute for Psycholinguistics, Australia’s QIMR Berghofer Medical Research Institute, and the US company 23andMe, Inc.
The study, according to lead researcher Michelle Luciano of the University of Edinburgh’s School of Philosophy, Psychology, and Language Sciences throws light on many unresolved problems about dyslexia.
Our findings show that common genetic differences have very similar effects in boys and girls, and that there is a genetic link between dyslexia and ambidexterity. Previous work suggested some brain structures may be altered in people with dyslexia, but we did not find evidence that genes explain this. Our results also suggest that dyslexia is very closely genetically related to performance on reading and spelling tests reinforcing the importance of standardized testing in identifying dyslexia.”
Dr Michelle Luciano, Reader, School of Philosophy, Psychology and Language Sciences, University of Edinburgh
Doust, C., et al. (2022) Discovery of 42 genome-wide significant loci associated with dyslexia. Nature Genetics. doi.org/10.1038/s41588-022-01192-y.