Study: Kids with ADHD more likely to have missing or extra DNA in their brains
LONDON - Children with attention deficit hyperactivity disorder are twice as likely to have missing or extra chromosomes than other children — the first evidence that the disorder is genetic, a new study says.
British researchers compared the genomes of 366 white British children from 5 to 17 years old with attention deficit hyperactivity, or ADHD, to those of more than 1,000 similar children without the disorder. The scientists focused on a sequence of genes linked to brain development that has previously been connected to conditions like autism and schizophrenia.
In children without ADHD, about 7 percent of them had deleted or doubled chromosomes in the analyzed gene sequence. But among children with the disorder, researchers discovered about 14 percent had such genetic alterations. Scientists also found that 36 percent of children with learning disabilities in the study had the chromosomal abnormalities.
"This is the first time we've found that children with ADHD have chunks of DNA that are either duplicated or missing," said Anita Thapar, a professor at the MRC Centre in Neuropsychiatric Genetics and Genomics at Cardiff University who was one of the study's authors.
She said the findings are too early to affect diagnosis or treatment and are only applicable to people of European Caucasian descent because studies have not been done yet on other ethnicities.
The condition is estimated to affect millions of children around the world, and scientists have long thought the disorder has a genetic component.
U.S. experts estimate that ADHD affects from three to five percent of school-age children in the United States. There are no figures for developing nations.
The study was paid for by Action Research, Baily Thomas Charitable Trust, the Wellcome Trust, Britain's Medical Research Council and the European Union. It was published online Wednesday in the medical journal Lancet.
LONDON - Children with attention deficit hyperactivity disorder are twice as likely to have missing or extra chromosomes than other children — the first evidence that the disorder is genetic, a new study says.
British researchers compared the genomes of 366 white British children from 5 to 17 years old with attention deficit hyperactivity, or ADHD, to those of more than 1,000 similar children without the disorder. The scientists focused on a sequence of genes linked to brain development that has previously been connected to conditions like autism and schizophrenia.
In children without ADHD, about 7 percent of them had deleted or doubled chromosomes in the analyzed gene sequence. But among children with the disorder, researchers discovered about 14 percent had such genetic alterations. Scientists also found that 36 percent of children with learning disabilities in the study had the chromosomal abnormalities.
"This is the first time we've found that children with ADHD have chunks of DNA that are either duplicated or missing," said Anita Thapar, a professor at the MRC Centre in Neuropsychiatric Genetics and Genomics at Cardiff University who was one of the study's authors.
She said the findings are too early to affect diagnosis or treatment and are only applicable to people of European Caucasian descent because studies have not been done yet on other ethnicities.
The condition is estimated to affect millions of children around the world, and scientists have long thought the disorder has a genetic component.
U.S. experts estimate that ADHD affects from three to five percent of school-age children in the United States. There are no figures for developing nations.
The study was paid for by Action Research, Baily Thomas Charitable Trust, the Wellcome Trust, Britain's Medical Research Council and the European Union. It was published online Wednesday in the medical journal Lancet.
