26 January 2014
New research into the genetics of the common (and serious) psychiatric disorder schizophrenia underlines links with specific brain functions.
Schizophrenia affects around 1 in 100 of the population and is characterised by abnormal thought processes, including hallucinations and delusions. The disease is known to arise from polygenic (involving variants in multiple different genes) as well as environmental influences.
Most schizophrenia cases occur in patients with a family history of the disease, and are therefore presumed to involve a significant inherited component. However, around 5% of cases occur without any family history and the role of de novo (new, non-inherited) mutations is thought to be important in these cases.
A study examining these rarer de novo mutations in over 600 schizophrenia patients reported that they are particularly common in genes for components of specific functional brain networks, a finding that could eventually be important for developing potential new treatments. The genes also showed significant overlap with those linked with other neurodevelopmental disorders such as autism, reinforcing previous findings.
In a second study, researchers used exome sequencing to examine de novo mutations linked with schizophrenia, using more than 2,500 patients and the same number of control (healthy) subjects. They too found the mutations clustered in genes for specific proteins involved in key brain functions, and reported that the mutations could have an important role in initiating the pathological processes underlying schizophrenia.
Shaun Purcell of the Broad Institute, who was involved in both studies, said: "Despite the considerable sample sizes, no individual gene could be unambiguously implicated in either study…It suggests that many genes underlie risk for schizophrenia and so any two patients are unlikely to share the same profile of risk genes".