While scientists sift through human DNA to find genes that increase risk for psychiatric illnesses, they occasionally run across something that seems to protect a person from these illnesses. Just this kind of protective effect for schizophrenia has been reported in a study published November 12th in Molecular Psychiatry.

A research team led by 2012 Foundation Lieber Prizewinners for Outstanding Achievement in Schizophrenia Research, Michael Owen, M.D., Ph.D., and Michael O’Donovan, M.D., Ph.D., at Cardiff University in the United Kingdom surveyed the genomes of 47,005 people, looking for an extra piece of chromosome 22, called 22q11.2. This region contains at least 30 different genes, and previous research has found that when it is missing, it drastically increases a person’s chances of developing schizophrenia. The researchers wanted to know the effects of having an extra copy of this 22q11.2 region.

Extra copies of 22q11.2 were rare in both control subjects (0.085 percent) and in people with schizophrenia (0.014 percent), but were much rarer in schizophrenia, occurring one-sixth as often as in the controls. This suggests that having extra copies of genes within 22q11.2 protects from schizophrenia, whereas having too few copies promotes it.

“To our knowledge, 22q11.2dup is the first putative protective mutation for schizophrenia that has been described in the literature. Our study suggests the existence of one or more dosage-sensitive gene in the duplication with the capacity to reduce risk of schizophrenia with implications here for further studies aimed at identifying targets for treating the disorder,” report the researchers.

Future research will have to zero in on which gene or genes in particular, but the new finding holds promise for the development of new ways to treat schizophrenia as well as offers clues about enhancing resilience among those who are generally thought to be at elevated risk of developing the illness.

Read more about this research on the Schizophrenia Research Forum.

Read more about this research in Molecular Psychiatry.