Schizophrenia: 10 new genes identified

In what is defined as one of the largest DNA sequencing studies related to schizophrenia, a group of researchers led by Tarjinder Singh has discovered 10 new genes implicated in the development of this pathology with a method called “whole-exome sequencing.” The researchers used genetic data from more than 125,000 people to obtain various information regarding the genetic basis of schizophrenia itself. The results of the research were then presented at the annual meeting of the American Society of Human Genetics 2019 in Houston.

One of the reasons that led researchers to use DNA sequencing to obtain information on schizophrenia is that for this disease, in the last fifty years, there has been quite limited progress regarding the development of new drugs. However, the use of new genetic techniques is proving very useful, in recent years, in many fields and the same researchers believe that useful results can also be obtained to discover mechanisms underlying schizophrenia.

The latter is one of the psychiatric disorders not yet fully understood. It is believed, however, that its development can be accelerated by disorders concerning some genes that encode certain proteins. Because these are rare genetic changes, the researchers used a very large set of people. Of the 125,000 people analyzed, 25,000 of them had been diagnosed with schizophrenia. People came from all five continents.

Following the analyzes, the researchers identified 10 genes that, once they stopped their functions, caused an increased risk of schizophrenia, as Singh himself stated in the press release. Two of these 10 genes encoded glutamate receptors, indicating that these receptors could potentially be a target for future therapies against schizophrenia.

Westernization has profoundly changed our microbiome

Lifestyle can change the intestinal microbiome, a sort of ecosystem of bacteria existing in our intestine that can have various roles and that can also be a support for our immune system. This is confirmed by a new study, which appeared in Cell Host & Microbe and was conducted by researchers from the University of Trento and Eurac of Bolzano, who made up above all the analysis of the remains of Ötzi, human remains found in 1991 in the Alps belonging to a man lived between 3300 and 3100 BC.

By examining the intestine specimens of Ötzi’s remains, the researchers confirmed that there is a connection between the microbiome bacteria and the lifestyle change that today distinguishes the Western world above all. In particular, the connection exists between the bacteria and the increase of conditions such as obesity, autoimmune and gastrointestinal diseases, allergies and other complex conditions. In the press release that presents the study, they talk about a “Westernization process” that has brought about profound changes in our diet and that has meant that today foods are much richer in fat and poorer in fiber. This, combined with a more sedentary lifestyle and the development of new hygiene habits as well as medical products of various kinds, while making our lives safer has profoundly affected our microbiome.

In particular, the researchers analyzed the Prevotella copri, an intestinal bacterium. Nicola Segata, one of the main authors of the study together with Adrian Tett of the CIBio of the University of Trento, explains that they first discovered that it is not a single species. In fact, the bacterium is part of four different species. They later discovered that three of them had always been found in the microbiomes of non-westernized populations rather than in westernized ones. When the bacterium is found in the intestines of westernized populations, it is usually of a single species, which of course goes to the detriment of diversification.

The researchers, therefore, thought that the same phenomenon of “westernization” of our habits, above all food habits, caused the decrease of the diversification of this bacterium in our intestines, which probably happened also for other species of bacteria not analyzed by researchers. This same hypothesis, according to Segata, is supported by the analyzes that the same researchers carried out on ancient DNA, which was possible with a collaboration with the Institute for the study of mummies of Eurac Research. In particular, analyzing Ötzi’s intestines, the researchers noticed that three of the species of this bacterium were present in his intestine.

This multiple presence can also be identified in various fossilized stool samples dating back over a thousand years ago and found in Mexico. Now the only thing to understand is to what consequences this decrease in the diversification of our intestine bacteria and in general the changes of our intestinal biome that are taking place over the last few centuries can bring, considering also that the human body itself has never substantially changed to genetic level during the same period.