Schizophrenia candidate genes affect even healthy i...( Philadelphia PA September 26 2007 D...),Health

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.

John H. Krystal, M.D
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