Scientists identify new genetic links to dyslexia

Potential implications for reading and spelling

“We were surprised that none of the previous dyslexia candidate genes were genomewide significant in our study; all of our discoveries were in new genes that had not been previously implicated in dyslexia,” Dr. Luciano said in an interview. “Some of these genes have been found to be associated with general cognitive ability, but most were novel and may represent genes specifically related to cognitive processes dominant in reading and spelling.

“We were also surprised that there was little genetic correlation (or overlap) with brain MRI variables, given that brain regions have been linked to reading skill. This suggests that the link is environmental in origin,” she added.

“Our results do not directly feed into clinical practice,” said Dr. Luciano. However, “the moderate genetic overlap with ADHD suggests that broader assessments of behavior are important when a child presents with dyslexia, as co-occurrence with other conditions might influence the intervention chosen. Asking about family history of dyslexia might also help in identification.

With more research, genetic studies may find a place in the clinical setting, said Dr. Luciano.  

“As genomewide association studies become larger and the findings more stable, genetic information might be used as an adjunct to what is known about the child’s environment and their performance on standardized tests of reading. The key advantage of genetic information is that it could allow much earlier identification of children who would benefit from extra learning support,” she said.

More research is needed to understand the interaction between genes and the environment, Dr. Luciano said. “It is essential that we understand what environmental learning support can minimize genetic predisposition to dyslexia.”
 

Too soon for clinical utility

The study findings are an important foundation for additional research, but not yet clinically useful, Dr. Lessin said in an interview.

“Dyslexia is a tough diagnosis,” that requires assessment by a developmental pediatrician or a pediatric neurologist and these specialists are often not accessible to many parents, Dr. Lessin noted.

In the current study, the researchers found a number of genes potentially associated with dyslexia, but the study does not prove causality, he emphasized. The findings simply mean that some of these genes may have something to do with dyslexia, and further research might identify a genetic cause.

“No one is going to make a diagnosis of dyslexia based on genes just yet,” said Dr. Lessin. In the meantime, clinicians should be aware that good research is being conducted, and that the genetic foundations for dyslexia are being explored.

Lead author Dr. Doust and corresponding author Dr. Luciano had no financial conflicts to disclose. Several coauthors disclosed support from the Max Planck Society (Germany), the National Natural Science Foundation of China, Funds for Humanities and Social Sciences Research of the Ministry of Education, and General Project of Shaanxi Natural Science Basic Research Program. Two coauthors are employed by and hold stock or stock options in 23andMe. Dr. Lessin had no financial conflicts to disclose, but serves on the editorial advisory board of Pediatric News.