Yale University
researchers say they've identified a gene that may be responsible for dyslexia,
one of the most common neurobehavioral disorders.
Dyslexia, a
reading disorder, affects up to 17 percent of the population.
Yale researchers
identified an inherited component to reading disability, and some potentially
responsible chromosome regions.
The most widely
reported region is on chromosome 6, which contains about 19 genes, most
of which are expressed in the brain.
Jeffrey Gruen
of Yale's Child Health Research Center and colleagues genotyped 153 families
affected dyslexia and located the likely source of the susceptibility region:
a deletion in the DCDC2 gene.
While that gene's
function is unknown, it is similar to DCX, a gene that helps guide neuron
migration in the brain. Gruen's team decreased DCDC2 gene expression in
rats and observed that neurons migrated shorter distances.
DCDC2 was also
found to be activated in the same brain regions in both fluent and dyslexic
readers, suggesting dysfunction, and not disruption, of the gene occurs
in those with reading disability.
Therefore, the
evidence supports the identification of DCDC2 as a dyslexia gene.
The research
appears in the journal Proceedings of the National Academy of Sciences.
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