"Oh, yes! GTS is at 11q23! I know that for a fact!Yes, yes, very interesting stuff."
"So, what does it do?"
"Do?"
"Yes, what does the gene do?"
"Well, it causes Tourette syndrome doesn't it!"
"How?"
"What do you mean, how?"
"What does the gene do that causes Tourette syndrome?"
"Well, I..."
"I'll make it simple. All genes code for proteins, right? So we must know what protein GTS affects."
"Oh, that's easy...we don't know.
"You don't know? Surely you can work it out from the amino acid sequence!"
"Theoretically yes..."
"Look, I know a bit about this. Just give me the string of letters and I'll work it out myself."
"ah! We don't know the string of letters."
"At all?"
"No."
This is a theoretical conversation between me and a member of the team that sequenced the GTS gene. We know a huge amount about different proteins and amino acids and genes and their effects. But despite sequencing the human genome, we still don't have a clue what these genes are or what they do.
If you're curious about this, visit the Gene card Tourette syndrome page to see how little we know.
To copy off the site:
| Start: |
unknown bp |
| End: |
unknown bp |
| Size: |
unknown bases |
| Orientation: |
unknown strand |
Oh yes! There's lots of information there! So if you go to 11q23 and travel from some point in some direction for some distance you'll have
covered the GTS gene. Thanks a lot!
Gene therapy may one day be very effective against Tourette syndrome.
First, however, we need to find out what that therapy needs to do.
Recently my father was discussing Schizophrenia with a Dr. Dean. Now we
know heaps about Schizophrenia. Compare
the Schizophrenia gene card to the Tourette syndrome gene card.
My father is not a geneticist, but he managed to relay a large amount of quite
technical information to me without understanding any of it. It seems that
schizophrenia is a maternal linked dominant disorder mostly caused by
disruptions in the D2 receptors of the brain.
Why is this interesting to me? (or even relevant?)
A quick glance at the types of medications used in Tourette syndrome show that
the majority are primarily used to
treat schizophrenia. This is because of an unnerving similarity between
the two conditions.
In Schizophrenia it has been found that the brain possesses more dopamine
receptors than a normal brain. It also releases more dopamine than a
normal brain.
A Tourette brain releases the same amount of dopamine as a normal brain, but has more dopamine receptors.
While this effect happens in different parts of the brain for
Touretters and Schizophrenics, the gene that controls this abnormal development
is likely to be similar. Now we know a bit about how the gene works in
schizophrenia, so we may be able to apply this to Tourette syndrome.
So what can that tell us?
Firstly, it explains why drugs that are designed to treat
Schizophrenia work in Tourette syndrome. It also explains why we need a
lower dose of these medications than they do.
More importantly, however, it tells us about where the genes act in the brain.
In Schizophrenia, they have found that this surplus of Dopamine occurs mostly in
the Occipital Lobe and Parietal lobe where the sounds, sights and other
sensory experiences are processed.
In Tourette syndrome, however, the activity is mostly in the Frontal lobe
where actions and sounds are produced.
Because these are the areas in both conditions where there is
an excess of activity, this supports the hypothesis that an excess of dopamine
getting through creates an excess of action.
So if, in the future, there are any significant breakthroughs
in curing Schizophrenia, then the same will probably apply to Tourette Syndrome.
And since millions of dollars are spent every year on Schizophrenia research, a
cure is not unlikely.