Genes common to dyslexia, ADHD discovered in study

New Delhi: Researchers have identified 174 genes shared between dyslexia and attention deficit hyperactivity disorder (ADHD), results that shed new light on their genetic origins.

The team, led by researchers at the University of Edinburgh, UK, said that of the 174 genes, 121 had not been previously identified. They also located 49 genetic regions shared between the neurodevelopmental disorders.

Dyslexia is marked by an impaired ability in reading and with spelling, while ADHD is a condition in which one faces difficulty concentrating, hyperactivity and impulsivity.

The findings, published in the journal Molecular Psychiatry, shed new light on the genetic origins of dyslexia and show how they overlap with those of ADHD, the authors said.

The results also help understand the biology behind dyslexia and ADHD, which can often occur together in people, but the genes underlying these conditions distinguish them from other mental diagnoses such as autism, bipolar disorder and schizophrenia, they said.

For the study, the researchers analysed genetic datasets from the Psychiatric Genomics Consortium (PGC). A global research community, the PGC brings together genetic data from people around the world to identify genes underlying psychiatric disorders and find variants that change risk of disease.

The researchers also used dyslexia genetic statistics from an analysis of around one million people in collaboration with 23andMe, a US-based genomics and biotechnology company.

The team used statistical tools to find clusters of genes underlying similar traits for dyslexia and 10 other neurodevelopmental and psychiatric traits, including ADHD, autism, bipolar disorder and schizophrenia.

“We further investigated genetic variants underlying both dyslexia and ADHD, which implicated 49 loci (40 not previously found in GWAS of the individual traits) mapping to 174 genes (121 not found in GWAS of individual traits) as potential pleiotropic variants,” the authors wrote.

GWAS refers to genome-wide association study, a research method which analyses genomes of several people to pin-point genes linked to a certain trait or disease. Pleiotropy is where the same variant of a gene is responsible for multiple traits simultaneously.

“This is the first time that genetic links to dyslexia have been studied in the context of psychiatric traits. In the future, other learning difficulties such as dyscalculia or dyspraxia should be included to allow for a more nuanced understanding of the relationships between them,” said lead researcher Austeja Ciulkinyte, a PhD student of translational neuroscience at the University of Edinburgh.