When parents discover that their child is one of the thousands out there who have attention-deficit hyperactive disorder, their first reaction is to find something to blame. Whether it is their playmates, their school, or even themselves, unnecessary stress goes into blaming. But new research puts things into perspective, and the culprit? A person's DNA.

According a study led by Hakon Hakonarson, MD, PhD, director of the Center for Applied Genomics at The Children's Hospital of Philadelphia, genetics has something to do with ADHD.

ADHD's symptoms vary from short attention span, to impulsive behavior and excessive activity. Having this in mind, the researchers estimated that this disorder affects as many as 7% of school-age children, and in smaller percentages in adults.

In the study, Hakonarson along with a research team analyzed the genomes of a thousand children with the disorder and compared it with 4,100 children without ADHD. Looking for copy number variations, which are deletions or duplications of DNA sequences, the researchers evaluated their initial findings in multiple independent groups that included around 2,500 cases with ADHD and 9,200 control subjects.

Through this, the researchers were able to identify four genes with a significantly higher number of copy number variations in children with ADHD. Researchers explained that these genes that they were able to identify belonged to a gene family that affects nerve transmission, the formation of neurons, and interconnections in the brain.

Josephine Elia, the study's co-first author, and a child psychiatrist and an ADHD expert, noted that though there may be thousands of genes that contribute to the risk of ADHD, indentifying a gene family responsible for m10% of cases is a significant step for treating the disorder.

Also sighting DNA as the one to blame, Maria Cheng of MSNBC reported back in 2010 that children with the disorder are twice as likely to have missing or extra chromosomes than those who do not have ADHD.

Meanwhile, in a different study about ADHD, American researchers found that this DNA-linked disorder has its effects on the brains of those who have it.

According to fMRI scans, those with ADHD have abnormal functional activity in several regions of the brain which are involved in visual attention information, as well as discovering that communication among the regions of the brain within the visual-processing pathway was disrupted.