September 27, 2007
Schizophrenia Risk Gene Carriers Show Mild Cognitive Differences

Schizophrenia risk genes cause cognitive differences even among people who do not develop full blown schizophrenia.

Philadelphia, PA, September 26, 2007 – Do gene variants that convey risk for schizophrenia affect apparently healthy individuals" Although these genes are present in every human, individuals may have different versions of these genes, called alleles. While many people who possess these “risk alleles” do not end up with schizophrenia, this does not mean they are unaffected by the presence of the risk allele. In the largest study of its kind to date, scheduled for publication in the October 1st issue of Biological Psychiatry, researchers sought to examine the impact of a few particular genes, known to be associated with a diagnosis of schizophrenia, on a healthy population.

Stefanis and colleagues recruited more than 2000 young men and measured dimensions of their cognitive abilities that tend to be impaired in individuals diagnosed with schizophrenia. The authors also measured schizotypal personality traits, which represent behaviors that are associated with schizophrenia, such as atypical behaviors and beliefs, suspiciousness or paranoia, and discomfort in social situations. They then genotyped these volunteers in relation to the four most prominent schizophrenia candidate genes: Neuregulin1 (NRG1), Dysbindin (DTNBP1), D-amino-acid oxidase activator (DAOA), and D-amino-acid oxidase (DAAO). According to Nicholas Stefanis, the lead author on the paper, their study showed “that apparently normal individuals who posses several risk alleles within these susceptibility schizophrenia genes, have indeed minute decrements in cognitive ability such as decreased attentional capacity and worse performance on memory tasks, and alterations in schizotypal beliefs and experiences.” In other words, they found that the healthy individuals who possessed the risk variants within the DNTBP1, NRG1, and DAAO genes exhibited small reductions in their cognitive performance and had atypical experiences that might be associated with schizophrenia.

How many people have atypical beliefs because they are smart enough to think their way outside the box of the conventional consensus? How many have atypical beliefs because they carry genetic variations that alter the way they view evidence?

Do we as a total society benefit from some people carrying alleles that make them think atypical thoughts? Are smart people with schizophrenia risk genes who do not get schizophrenia more creative, on average, than smart people without these schizophrenia risk genes? Is there some optimal small dose schizophrenia risk alleles that, when combined with high IQ, produces great scientists, inventors, and innovators? Whatever genes made the unusual mind of Vincent Van Gogh might get clipped out of future generations of humanity.

One of my concerns with mental illness risk genes going forward comes from the ability we are gaining to screen and choose amongst our genes to decide what to pass on to our offspring. Will prospective parents take such a risk minimizing approach to offspring genetic allele selection that future generations will have brains that make them more likely to accept the conventional wisdom and to go along with the consensus of elites and masses? Will future societies become more sheepish and less free as a result?

Share |      Randall Parker, 2007 September 27 06:31 PM  Brain Genetics

james said at September 28, 2007 7:02 PM:

I personally believe that smart people with schizophrenia risk genes do as result of these genes have enhanced creativity and atypical thoughts. It seems highly likely that there will be selective pressure to eradicate these schizophrenia risk genes, as they could be viewed as defects. People with normal IQ’s and schizophrenia risk genes are usually looked at as dysfunctional; however, if there is a high IQ or in some cases a genius IQ, society may accept the quarks, as these people may be adding something to society. In the future, however, there will likely be more people with high and genius IQ’s without the schizophrenia risk genes and these people will likely put pressure on the people with schizophrenia risk genes to undergo genetic engineering to remove the undesirable traits. The understanding of how schizophrenia risk genes could benefit someone (by enough of the majority) will likely occur after the pressure to engineer this trait out of someone. Wisdom will likely be the last the thing to understand and or manipulate in someone, as it is much more complex than general cognitive ability.

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