On Jan. 25, 2024, a study led by the University of Edinburgh, is the largest genetic study of dyslexia to date. Previous studies linking dyslexia to specific genes have been done on small numbers of families and the evidence was unclear, the research team says.

Dyslexia is known to run in families – partly because of genetic factors – but, until now, little was known about the specific genes that relate to the risk of it developing.

This latest study involved more than 50,000 adults who have been diagnosed with dyslexia and more than one million adults who have not. Researchers tested the association between millions of genetic variants with dyslexia status and found 42 significant variants.

Some of these are associated with other neurodevelopment conditions, such as language delay, and with thinking skills and academic achievement. Many, however, are novel and could represent genes that more specifically associate with processes essential for learning to read.

Many of the genes associated with dyslexia are also associated with attention deficit hyperactivity disorder. A much smaller overlap of the genes associated with dyslexia was found for psychiatric, lifestyle and health conditions.

Several of the associated genetic variants were also significant in a Chinese speaking sample suggesting that there are general cognitive processes in learning to read that are not dependent on the type of language.

Researchers say they were able to predict how well children and adults from four other research studies can read and spell using the genetic information from the study, but not with the accuracy needed for diagnostic use.