Researchers studying the biological basis of mental illness, spent the first genomic analysis of schizophrenia of the people of Africa and identified multiple rare mutations that are more common in people with this disease. Mutations were mostly found in genes that are important for brain development and brain synapses — the tiny structures that coordinate the communication between neurons. Discovered genes correspond to genes identified in other similar studies of schizophrenia, however, almost all previous studies were conducted in European or Asian countries. The paper was published in the journal Science.
The results of the study consistent with the current hypotheses about the biological origin of schizophrenia, which can cause a number of symptoms such as hallucinations, delusions and disordered thinking. Researchers believe that each mutation can make a small contribution to the overall risk of developing the disease, and the disruption of synapses may be crucial for the development of the disease.
Since the last decade, studies of genome sequencing has flourished, making it possible to detect many diseases. However, the researchers often criticized for not have been able to select different groups of the population, mostly ignoring the Africans. About 80% of all participants in genetic research are of European origin, and less than 3% African. This shift means that diagnostic tests and therapies developed on the basis of narrow studies may not work in certain groups of the population. Thus, the study of 2016 showed that the genetic tests that calculate the risk of fatal cardiovascular disease, often led to misdiagnosis. This happened because the genes on which it was based, were identified in the studies that did not participate came from Africa, which, as a rule, many different gene variantsthat affect the risk of developing diseases.
Studies in different populations also allow scientists to gain a more complete picture of the disease. In particular, some inhabitants of Africa presents a more diverse genome than other populations. Moreover, it contains a large number of unique gene variants. The researchers attribute this to the fact that the greatest period of human evolution occurred in Africa, the origin of modern Homo sapiens. It is believed that humans left Africa 50 000-100 000 years ago and only a relatively small number of people migrated to Europe and Asia. As a result of genetic diversity in these regions is much more modest.
Does the severity of schizophrenia on the results of the study?
A recent study conducted by researchers in South Africa and the United States, was attended by approximately 900 people with schizophrenia and the same number of people who had this disorder. All participants identified themselves as Xhosa — large representatives of ethnic groups living in South Africa.