All in the Family? The Genetics of ADHD

Are scientists able to break the genetic code that causes ADHD? Can they eliminate it from the family tree? A brief explanation for ADD Genetic research…

Attention deficit hyperactivity disorder (ADD ADHD) is an illness of the brain that could be caused by a variety of causes. Family studies suggest that genetic factors are responsible for ADHD. It is believed that it may “run in families”, at the very least, in some families.

If children are diagnosed with ADHD it is a high chance that it could be present in blood relatives of other blood relatives as well. For instance, research has revealed that one-third of men with ADHD as children have children born with ADHD.

Numerous research studies are being conducted throughout both the U.S. and Europe to seek out genetic factors that cause susceptibility to ADHD.

Our team has two studies that fall within the norm of how genetic studies are conducted. The first research project involved obtaining clinical data as well as DNA from 18 massive, extended families from Colombia, South America. Together with our Colombian colleagues as well as Professor Dr. F. Xavier Castellanos from New York University, we are currently looking into the DNA of over 400 members of these families.

Another study is being conducted as well in the United States. We are seeking families with at least two kids; at the very least, one child within the family is likely to be diagnosed with ADD or ADHD. We are trying to recruit all families, including fathers, mothers as well as all children, even those who don’t have a diagnosis of ADD or ADHD.

Decoding the DNA of ADHD

Research into how genetics influence susceptibility to ADHD is ongoing. Two research groups, one located in California and the other located in the Netherlands, have found evidence of linkage across several human chromosomes. Linkage is the intermingling between two genes within the same area on a chromosome. A chromosome is a cellular structure within the nucleus of the cell that contains genetic information.

We suggest that a particular gene, a portion of DNA that contains “instructions” for forming a functional “product”(ADHD for instance) has been “linked” to another marker gene on a chromosome when they are located so close to each other that they always have the same gene in common. Our unpublished research suggests that two of the regions that the California and Dutch groups have discovered are relevant to us.

The main thing is to examine more families as the capacity to identify linkages is increased with increasing families. As we study larger and smaller families suffering from ADHD the research group from the National Institutes of Health in Bethesda, Maryland, and our colleagues from California, as well as The Netherlands, can begin to identify the causes of genetics that cause ADHD. The knowledge gained could help tailor treatment options for children or an adult who suffers from ADHD that are based on the root reason.

ADHD in the Family Tree?

For families interested in participating in our study call, send us an email or write us. They consent to an interview with an RN or social worker who is part of our team of researchers. The family members also consent that every family member will provide some tablespoons of their blood (drawn by their physician or local laboratory) to us to be able to use for genetic research.

The interviewer will spend about an hour talking to any of their parents,, asking questions regarding the family’s physical and mental health background. The interviewer utilizes the data to create an individual phenotype for every family member. A phenotype, in this case, refers to whether or not a person is suffering from ADHD.

The interviewer draws the pedigree, also known as a family tree, that shows each individual in the family as well as how they relate to one another. All information about a family’s history is kept in encrypted files so that only the research team is able to look at it.

When we have phenotype data on a family as well as a blood tube from every family member we can extract DNA in the blood. DNA codes the chemical language that identifies genes. While everyone, with the exception of identical twins, has their own unique combination of genes, or genotype, siblings, and brothers have DNA that is shared by their parents. We’re trying to find the same DNA pattern identical in those with ADHD as well as different from the people who do not suffer from ADHD.

Our work is somewhat easier since our colleagues at the Human Genome Project have sequenced our genetic code. However, we need to do a lot to complete it. The identification of genes that cause ADHD can help in making the diagnosis simpler. It could be a way to discover better treatment options for those who suffer from ADHD.