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Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.
However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”
Currently, genetic testing for dyslexia alone is not done.
“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.
There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained.
Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.
In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.
The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.
The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.
A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.
The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.
The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
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.
Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.
However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”
Currently, genetic testing for dyslexia alone is not done.
“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.
There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained.
Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.
In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.
The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.
The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.
A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.
The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.
The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
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.
Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.
However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”
Currently, genetic testing for dyslexia alone is not done.
“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.
There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained.
Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.
In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.
The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.
The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.
A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.
The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.
The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
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.
FROM NATURE GENETICS