A gene which is likely to be one of the causes of dyslexia in children has been discovered by researchers at Cardiff University.
They believe the major finding will give researchers a better understanding of what causes the brain disorder which disrupts reading and writing skills.
It is now hoped that follow-up research will also lead to the discovery of treatments which could help children susceptible to dyslexia.
The discovery was made by a team from the Department of Psychological Medicine, Wales College of Medicine.
They carried out analysis of 300 families from Wales and the West of England where at least one child suffered from the disorder.
The research team led by Professor Julie Williams and Professor Michael O'Donovan will now continue their study in order to discover more about the gene called "KIAA0319".
The research will focus on discovering exactly how the gene works within the brain to disrupt reading and writing skills.
Professor Williams said: "This is a major breakthrough and the first study to identify one gene which contributes to susceptibility to the common form of dyslexia. We would like to thank all the parents and children who took part in the study and would extend a call to new volunteers to take part in this important research."
The researchers want to hear from more families with at least one child who has dyslexia.
Professor O'Donovan said: "The finding vindicates our optimism that a disorder as apparently complicated as impaired reading ability can be amenable to molecular genetic dissection." However, he added: "Much more remains to be done before the finding is translated into therapy. To tackle the genetic origins of disorders like dyslexia, both quality of assessment and sample size are crucial. We have the tools to take care of the latter, but we are entirely dependent on the altruism of the public in offering their time and DNA".
Cardiff University
Scientists Link Gene To Dyslexia
Slow Reading In Dyslexia Tied To Disorganized Brain Tracts
Dyslexia marked by poor reading fluency -- slow and choppy reading -- may be caused by disorganized, meandering tracts of nerve fibers in the brain, according to researchers at Children's Hospital Boston and Beth Israel Deaconess Medical Center (BIDMC). The study, using the latest imaging methods, gives researchers a glimpse of what may go wrong in the structure of some dyslexic readers' brains, making it difficult to integrate the information needed for rapid, "automatic" reading.
The study was led by Christopher Walsh, MD, PhD, chief of the Division of Genetics at Children's Hospital Boston, and Bernard Chang, MD, a neurologist at BIDMC.
"We looked at dyslexia caused by a particular genetic disorder, but what we found could have implications for understanding the causes of dyslexia in other populations as well," says Walsh, who is also a Howard Hughes Medical Institute investigator at BIDMC.
Dyslexia, which affects 5 to 15 percent of all children, has different forms. Subjects in the study had reading problems caused by a rare genetic disorder known as periventricular nodular heterotopia, or PNH. Although their intelligence is normal, people with PNH have trouble reading fluently, or smoothly, lacking the rapid processing necessary for this aspect of reading.
The genetic mutation that causes PNH disrupts brain structure. In a normal brain, much of the gray matter (consisting mostly of nerve cells) appears on the brain's surface, while white matter (consisting mostly of nerve fibers or "wiring" connecting areas of gray matter) runs deeper in the brain. In PNH, nodules of gray matter sit deep in the brain's core, in the white matter, having failed to migrate out to the surface as the brain was developing.
To learn more about how these developmental changes in the brain might lead to reading problems, the researchers tested cognitive skills needed for reading in 10 patients with PNH, 10 individuals with dyslexia without neurological problems, and 10 normal readers. They used a specialized form of MRI called diffusion tensor imaging to look at the structure of the white matter in the brain.
In PNH patients, unlike in normal readers, white matter fibers took circuitous routes around the misplaced gray matter, and in some cases, didn't organize into uniform bundles, which could leave regions of gray matter poorly connected. Importantly, the more disorganized the PNH patients' white matter, the less fluent their reading.
While other studies have found disorganized white matter in the general population of people with dyslexia, these individuals often struggle with several aspects of reading, making it "hard to know exactly what the role of white-matter integrity is in isolation," says Chang. By demonstrating white-matter problems in PNH patients, who have an isolated reading fluency problem, and correlating that with reading fluency scores, the researchers were able to conclude that white-matter integrity and organization may be the structural basis in the brain for reading fluency.
"This makes sense," says Chang. "When we read, we need to take in information visually, hook it up with our inner dictionary of what letters and words mean, and when we're reading aloud, connect that with the region that gives us our ability to speak." For smooth, automatic reading, "the white matter is there to connect different regions of gray matter and allow them to function seamlessly." When reading fluency is the primary problem, "it may be that the areas of the brain that are important for reading are not connected efficiently," says Chang.
Most people with dyslexia who have trouble reading fluently don't have misplaced gray matter or PNH. But Walsh and Chang believe that disorganized white matter could similarly alter brain function in both groups. Their next study will examine how faulty white-matter connections alter brain patterns, comparing brain activation during reading in PNH patients and in dyslexic readers with poor fluency, who do not have PNH.
"Our findings suggest that white matter integrity plays a critical role in reading fluency and that defects in white matter serve as the structural basis for the type of dyslexia we see in this brain malformation," said the study's lead author Bernard S. Chang, MD, with Harvard Medical School in Boston, and member of the American Academy of Neurology. "Our work highlights the importance of studying white matter structure in order to understand cognitive problems and learning disabilities more fully."
Pinpointing the brain structures responsible for fluent reading may eventually help researchers and educational specialists develop and use techniques that help improve the automatic nature of reading in children and adults with these kinds of difficulties, the researchers note.
Findings will appear in the journal Neurology on December 4. The study was funded by the National Institutes of Health and the Mind-Brain-Behavior program at Harvard University.
Children's Hospital Boston.
Pre-school Age Exercises Can Prevent Dyslexia, New Research Shows
Atypical characteristics of children’s linguistic development are early signs of the risk of developing reading and writing disabilities, or dyslexia. New research points to preventive exercises as an effective means to tackle the challenges children face when learning to read.
The results achieved at the Centre of Excellence in Learning and Motivation Research were presented at the Academy of Finland’s science breakfast on 21 August.
Headed by Professor Heikki Lyytinen at the University of Jyväskylä, the research has dug deep into how to predict and prevent difficulties in learning to read and write. The study involved a comparison between 107 children whose either parent is dyslexic and a control group of children without a hereditary predisposition to dyslexia. The researchers followed intensively the development of the predisposed children, from their birth through to school age.
“Half of the children whose parents had difficulties in reading and writing found learning to read more challenging than children in the control group. The atypical characteristics of these children’s linguistic development indicated the risk at a very early stage, and we were also able to draw a clearer picture of the typical progression of a development that indicates reading and writing difficulties,” says Lyytinen.
According to Lyytinen, the predictors of reading and writing difficulties are evident primarily in two contexts: on the one hand as a delayed ability to perceive and mentally process the subtleties of a person’s voice, on the other hand as a sluggishness in naming familiar, visually presented objects. When approaching the age when they acquire the ability to read, the children seem to have more difficulties than expected to store in their memory the names and corresponding sounds of letters.
“Acquiring the ability to read demands much more practice from these children than from their peers. The automatisation of reading poses an additional challenge. Also, a fluent ability to read is a prerequisite to be able to understand a demanding piece of text,” says Lyytinen. “A slow reader isn’t able to grasp a given text as a whole, and therefore has a hard time following the storyline. This is why we should pay special attention not only to the accuracy of reading and writing but also to the comprehension of texts even with quite long sentences.”
Computer game to aid learning
The difficulties children experience when learning to read can be significantly reduced through training – “and in a way that children find amusing, even if they do have difficulties in learning to read,” Lyytinen points out.
The CoE in Learning and Motivation Research has developed computer game-like learning environments to aid preventive training, and made them available on the internet free of charge. They are especially recommended for children with a perceived risk of developing reading and writing disabilities or who have had a hard time learning to read already in first grade.
“The best time to start these exercises is the latter part of the pre-school age, but it’s not too late even after the children have started school. The learning result, of course, improves with repeated training: more than once a day and in short sessions. The optimal time for a single playing session is however long the children find it enjoyable.”
Researchers at the CoE in Learning and Motivation Research have made good use of a wide range of scientific disciplines in creating the learning environment. Apart from psychology, the exercises include elements from phonetics, mathematics and information technology. This has allowed the researchers to make the learning environment more effective than traditional educational games.
With funding from the Ministry of Education and in collaboration with researchers of the Niilo Mäki Institute, the researchers at the CoE are also working to create constantly-developing, game-like exercises as well as tools with which to identify risks and detect learning disabilities. The exercises and tools are all available at the same address http://www.lukimat.fi.
To access the learning environment, go to http://www.lukimat.fi
Suomen Akatemia (Academy of Finland)
Dyslexia may be in your genes
German researchers say that dyslexia, a learning disability whose sufferers struggle Dyslexia may be in your genes with reading and writing, can occur due to genetic Dyslexia may be in your genes causes.
“We are trying to find out which genes cause the disease. A predisposition to dyslexia could be detected by a genetic test to support affected children appropriately at a very early age,” says Arndt Wilcke, scientist at the Fraunhofer Institute for Cell Therapy and Immunology (IZI) in Leipzig.
The researcher says that the migration of nerve cells to their designated positions during brain development at the embryonic stage is routed by specific genes, which, when defective, can be a cause for dyslexia.
Wilcke points out that evidence for responsible “dyslexia genes” is already existing, and the first steps towards a genetic test have been taken.
However, reckons the researcher, at least five more years will be needed to reach that aim.
