A new gene has jumped into the mix of factors that might predispose people to schizophrenia. If additional work supports the finding, the study may provide researchers with potential new drug targets for the disease.
People with schizophrenia suffer hallucinations, delusions, and deteriorating social skills. Researchers believe the disease may be up to 80% genetic, with environmental or physiological factors accounting for the rest. As many as 10 different genes have been found that predispose people to schizophrenia to varying extents. But additional chunks of chromosomes also associate with the condition, including at least two to three large regions on chromosome 5.
To take a closer look at the role played by chromosome 5, molecular psychiatrist Hugh Gurling at University College London and colleagues examined 450 volunteers with schizophrenia and 450 volunteers with no family history of the disease. Different versions of genes can vary at single points in their sequence, and these variations are called SNPs. The team found that particular SNPs were more common in schizophrenics than in volunteers without the disease. Two of the SNPs lay within a gene called Epsin 4, the researchers report online 25 March in the American Journal of Human Genetics. Epsin 4 is responsible for making a protein involved in packaging and releasing the neurotransmitters that nerve cells use to communicate with one another, and obvious Epsin 4 mutations can now be sought in schizophrenics, the researchers say.
Scientists must replicate the findings in other ethnic groups to rule out nearby, as-yet-unidentified genes, says molecular geneticist Richard Straub of the National Institute of Mental Health in Bethesda, Maryland. Psychiatrist Doug Levinson cautions more strongly that it is far too early to say whether Epsin 4 contributes to susceptibility to schizophrenia. But with all the effort being put into researching the disease, he says, "maybe 5 to 10 years from now we will have some idea of how schizophrenia works."