ADHD Protein on "Speed"?

ADHD treatment options and resources

New mutation found on an "ADHD gene"

I was going to post some more information on the second ADHD gene on the list, but I recently came across a very interesting article on genetic mutations and ADHD, which can be found here.
The original study was recently published in the July 9, 2008 issue of the Journal of Neuroscience by the groups of Aurelio Galli and Randy Blakely. Several subtypes of ADHD are thought to be caused by an imbalance in the levels of of dopamine, an extremely important chemical found in the brain and nervous system that regulates proper neural functioning. There is an ideal balance between the amount of dopamine that is stored in neurons and the amount that is present in the "gaps" between different neuron cells.

It is here, that a critical protein comes into play. A special protein called the Dopamine Transporter (DAT) protein acts as a type of "shuttle" or "ferry" that helps balance dopamine levels inside and outside of the neuronal cells by aiding in the transport of dopamine in and out of the cells. This protein is actually "coded" for by the third ADHD gene on the list of a recent post.

It is strongly suggested that individuals diagnosed with ADHD have lower than normal levels of this dopamine in the gaps between neuron cells. As a result, a number of ADHD drugs focus on this DAT "shuttle" in an attempt to manipulate its ability to clear dopamine to the cells (think of the analogy of building a dam to trap and collect a stream of water in a region where it is scarce). In essence, this helps "fix" the problem of the low dopamine levels in this space, which is associated with ADHD.

Here is where it gets interesting. A rare mutation causes this shuttling DAT protein to essentially run in reverse at high speeds. Instead of "mopping up" dopamine and carrying it into the surrounding neurons, this mutated form of the protein essentially "squeezes" dopamine out of the cells and into the open space. This mutant protein actually functions in a very similar way to amphetamines such as the popular ADHD drug Adderall (which, incidentally, is chemically similar and has a similar, but much more benign, mode of function as the drug "Speed"). Here lies the paradox-- we would think that this mutated transporter protein, which behaves like a drug used to treat ADHD would be beneficial for ADHD individuals. However, the opposite is true. Individuals which possessed this mutation exhibited noticeable ADHD behavior.

Further complicating the issue is the fact that Adderall, while behaving much like this mutation by making the DAT shuttle run backwards, actually blocks some of the key negative effects of the mutation. Think of it as an almost homeopathic-like solution, treating "like" with "like". Ritalin, another ADHD medication which, in turn, can counteract the ability of Adderall to make this shuttle protein move backwards. For sake of brevity, I will save this discussion for a later post in the near future!

Finally, it is also interesting to note that this DAT mutation is very rare. Outside of this study, only one other case had been seen by the researchers, that of a bipolar girl. I found this interesting because it is sometimes difficult to distinguish differences between ADHD and pediatric bipolar disorders. The overlap of this mutation between the two disorders may lend some credence to underlying genetic mechanisms that both disorders seem to share.

ADHD treatment options and resources

ADHD gene #1 (DRD4)

The ADHD genes

ADHD treatment options

On my last post on ADHD treatment options I listed 7 different genes that have been found to be affiliated with ADHD. We will be focusing on the first listed ADHD gene in this post, the Dopamine D4 receptor gene (DRD4).

ADHD Gene #1: Dopamine D4 receptor gene (DRD4): exon III VNTR, 7-repeat

* A quick note: The"exon III VNTR, 7-repeat" bit listed above is a type of nomenclature used by geneticists to describe where on the gene the "ADHD allele" is found. Since genes can be fairly long (the "average" gene for humans is thought to be over 10,000 blocks of DNA strung together), this nomenclature is used to pinpoint both the location and what type of DNA the "ADHD form" of this gene contains. Genetic screeners will look to see if this form is present to assess your "genetic risk" for ADHD. For those of you who are interested or are familiar with genetics, I will include this information for these 7 ADHD genes, otherwise, feel free to ignore this extra info!

This gene is located on the 11th chromosome of the human genome. It is perhaps the gene most commonly affiliated with ADHD, and some studies suggest that the "ADHD allele" mentioned above is tied to nearly doubling the likelihood of an individual having ADHD. Based on research up to this point, the DRD4 gene has, potentially, the strongest correlation to ADHD for the aforementioned ADHD genes. This gene is highly associated with the frontal region of the brain (frontal subcortex), and is more affiliated with the inattentive component of ADHD than the hyperactive one, which suggests that this gene may be more tied to ADD than most of the other 6 ADHD genes listed previously.

ADHD genes and treatments

7 ADHD Genes

ADHD treatments

Is ADHD genetic?

As genetic screening and genomic sequencing continue to roll along, we have made a number of interesting discoveries about ADHD and potential ADHD treatment options. A 2006 article in the Journal of Clinical Psychiatry called "Candidate Gene Studies of Attention-Deficit/Hyperactivity Disorder" by Stephen V. Faraone and Sajjad A. Khan examined some of the studies on some of the specific genes that are affiliated with ADHD. A number of these genes relate to the manufacturing, transport and modification of two key compounds involved in the brain: serotonin and dopamine. Both of these play a critical role in regulating the attention span, imbalances of one or both of these are associated with different forms of ADHD.

***These next 2 paragraphs give a basic explanation of human genetics relevant to our discussion. If you are already familiar with the terminology, these two paragraphs may be omitted. If you would like additional background information on terms such as genes, alleles, DNA and chromosomes, and how they relate to our topic of ADHD, please click here.

Before we go any further, I just want to make sure that we are on the same page as far as discussing genes related to ADHD and its potential treatment options are concerned. If you are not familiar with genetics, a gene is simply a segment of DNA that acts as a "blueprint" to the body to manufacture specific proteins that ultimately determine hair color, eye color, and even built-in-resistances to certain diseases. For humans, there are about 30,000 different genes (this number, however, is widely debatable), which are scattered throughout 23 pairs (46 total) of chromosomes. This averages out to roughly 1000 different genes per chromosome.

It is important to note that while a specific gene is extremely similar amongst different people(down to a fraction of a percent difference), there are slightly different forms of the same gene, which vary from person to person. These different forms are called alleles of the gene. These alleles can result in some huge differences among different individuals and play a major role in the great diversity of our species. If an individual has a particular form (allele) of one or more of the seven genes listed above, he or she has a higher likelihood of exhibiting ADHD behaviors. For those interested, genetic screening is available to see if an individual possesses one or more of the "ADHD alleles" for seven different genes listed below.

Seven genes that are thought to be tied to ADHD are as follows:

ADHD gene #1. Dopamine D4 receptor gene (DRD4)

ADHD gene #2. Dopamine D5 receptor gene (DRD5)

ADHD gene #3. Dopamine transporter gene (DAT)

ADHD gene #4. Dopamine beta-hydroxylase gene (DBH)

ADHD gene #5. Serotonin transporter gene (5-HTT)

ADHD gene #6. Serotonin receptor 1B gene (HTR1B)

ADHD gene#7. Synaptosomal-associated protein 25 gene (SNAP 25)

I will discuss each of these "ADHD genes" and how some of them are related to the various ADHD treatment options in more detail in my upcoming posts, so stay tuned!

ADHD genes

Welcome Page

Welcome to my Blog on ADHD treatment options. It is my goal to present you will information and unbiased insight into the various ADD and ADHD treatment options that are out there. The information presented in this blog has been collected from a number of published studies in the field of attention deficit disorders and the effectiveness of a number of ADHD treatment options. I will be reporting on a number of journal articles and attempt to give an earnest evaluation of their results, citing relevant sources when necessary. My main goal is to present to you the most comprehensive, accurate and honest evaluations of the many ADHD treatment options available to you or your loved ones. I welcome your comments and encourage you to subscribe to my blog. You will receive constantly-updated information as my personal research in the field continues.

ADHD treatment options

This will discuss the root causes of ADD and ADHD as well as ADD and ADHD treatment options. We will evaluate some of the more well-known ADHD treatment options out there today, but will also explore some of the less well-known ADHD treatment options and their potential use as viable alternatives.