Two targeted genes may be responsible for dyslexia.
CANADA -- Dyslexia, which affects nearly 5 percent of elementary school children, is characterized by hearing, spelling, and writing difficulties. Now four independent studies from around the world have implicated two genes responsible for the disorder.Both of the targeted genes produce proteins that assist neurons in the early stages of brain formation. In people with dyslexia, variants of a gene known as DCDC2 are present.
In a study published in the Proceedings of the National Academy of Sciences (November 2005), one group examined the deoxyribonucleic acid (DNA) sequence in the crucial chromosome-6 region. Differences in DNA specific to reading disabilities appeared only in DCDC2.
In laboratory tests, the research team observed high concentrations of DCDC2 protein in areas of the brain that were active during reading.
A pair of English studies connected dyslexia to variants of a second gene in the same chromosome region as DCDC2. This gene, known as KIAA0319, also influences neurons in the brain while the brain is being formed.
That Canadian study, published in the April 2005 issue of American Journal of Human Genetics, reported that variations of KIAA0319 often appeared in 223 children who had dyslexia but not in 273 children without the disorder. A study completed by the University of Oxford independently confirmed those results, according to Anthony P. Monaco, a geneticist at Oxford.
It is thought that both genes contribute to the development of dyslexia, but it is not clear how or whether they interact with each other in the body.
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| Title Annotation: | MEDICAL NEWS FROM AROUND THE WORLD |
|---|---|
| Publication: | Nutrition Health Review |
| Article Type: | Brief article |
| Geographic Code: | 1CANA |
| Date: | Mar 22, 2005 |
| Words: | 248 |
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