Single gene key to schizophrenia
Researchers studying a gene called DISC1, previously implicated in schizophrenia, have seen evidence that it is essential for normal brain development. Their study showed that when this gene is mutated, the growth of brain cells is disrupted, leading to the development of schizophrenic symptoms.
Studies of mouse embryos showed large amounts of DISC1 in brain stem cells and normal brain growth. Further investigations on adult mice brain stems also showed high levels of the gene. However, when the scientists simulated presence of the mutated gene, the cells failed to grow and divide. The mice were observed in their cages and did a swim test (commonly used to test the effectiveness of antidepressants). The DISC1-deficient mice did not swim for long and were ‘skittish’ in their cages, behaviour associated with mental illness, and schizophrenia.
Interestingly, the team discovered that protein produced by the gene inhibits the same enzyme, GSK3beta, as lithium. Lithium is commonly prescribed to patients with mental illness as a mood stabiliser. In DISC1-deficient mice treated with a molecule that inhibits the enzyme, brain stem cells return to normal, producing new neurons, and restoring normal behaviour.
The identification of the part of the DISC1 protein that affects the enzyme may provide new ways of treating schizophrenia. The next stage is to identify additional variations in the DISC1 gene.