The new research examined DNA sequences within individuals’ genes, looking for what are called “mutations” — uncommon deletions or duplications that scientists wouldn’t ordinarily expect to find. We’ll let ScienceNOW summarize the findings from the journal article from Science:
One team [of researchers] found these rare so-called copy number variants in 15% of 150 schizophrenics they surveyed. Only 5% of 268 healthy controls carried the same variants. The other team [of researchers] examined DNA from 83 people with severe forms of the [schizophrenia] disease diagnosed before the age of 13 and compared them with 77 controls. Among this early-onset group, 20% had rare copy number variants — four times the rate in the controls.
So the news media is reporting on the obvious, nice takeaway from the study — that people with schizophrenia are 3 to 4 times more likely than people without schizophrenia to have this genetic mutation. Great stuff, that data.
But here’s the less-reported takeaway that I think is equally important to keep in mind — these gene mutations do not occur in the vast majority of people with schizophrenia (85% in the first study, and 80% in the second study).
That means that, even in an ideal world, if a genetic test or such were developed to look for this mutation, it would miss 80-85% of the people who took it — people who would still go on to develop schizophrenia.
But the gene mutation picture gets even cloudier:
Nor are [these mutations] unique to schizophrenia–they “probably will show in a variety of developmental disorders,” particularly mental retardation and autism, added Judith Rapoport, leader of the NIMH team. In fact, some of the authors of the current paper last year reported a similar pattern of rare and idiosyncratic mutations in people with autism
In other words, these kinds of mutations identified may be present in multiple disorders. We don’t know exactly how many yet. Might just be 3, but it could be 23. We don’t know.
Researchers’ optimism notwithstanding that they’ll eventually identify all such mutations (scientists are the penultimate optimists!), you only find the restrained acknowledgment of the limitations of this research at the very end of the ScienceNow story — one sentence — followed by additional future-looking statements about what might happen if any of this leads to anything, well, concrete to everyday practitioners and their patients.
Mainstream media reports have done little better, parroting the NIMH press conference on the findings and offering little in the way of a critical eye. The Washington Post, for instance, led with this zinger of a headline, “Schizophrenia Linked to Rare, Often Unique Genetic Glitches.” Indeed, so rare that they occur in only a small minority of people with schizophrenia, and so “unique” that they are found in other disorders like autism. Way to hit that one out of the ballpark, Post editors. But this is the best line in the article:
In the long run that could help doctors choose the best medications for individual schizophrenics and speed the development of drugs tailored to certain patients’ needs.
What is this “long run?” Ten years? Twenty? One hundred years? The reader is left to wonder.
Yes, researchers have only been talking about designer drugs tailored to specific patients’ needs for what, oh, a decade or two? And how many drugs have we even seen enter the pipeline during that time that can do anything approaching this? How many drug companies will create a drug tailored to a genetic mutation found in 1/10th (the throwaway number NIMH director Tom Insel suggested at the press conference) of 15% of people with schizophrenia (which affects approx. 1% of the population). So that’s about 3 million Americans and 15% with the genetic mutations is 450,000 and 1/10th of that is 45,000 people. Yeah, I don’t see drug companies clamoring for a market of 45,000 people anytime soon, sorry to say.
Don’t get me wrong — I’m all for breathless discoveries of scientific import. And I believe this actually is one of the few genetic discoveries that might hold some importance in the future, especially to researchers in this area.
But I gotta draw the line when mainstream media reports on this discovery as though it’s actually going to change the lives of anyone who suffers with schizophrenia right now, or heck, even in their lifetimes. We’re talking about an important step in the process of understanding, not a giant leap forward in having figured all of this genetic stuff out.
Just a little perspective from a skeptical eye.
Read the full news story at ScienceNow: Rare Mutations Hint at Multiple Schizophrenias