Identifying the missing heritability of complex diseases leveraging biobanks, registries and novel analytical tools in psychiatric disorders

Through international collaboration, leading researchers in the field of psychiatry have studied thousands of DNA sequences. In a recent study published in the prestigious journal Nature Genetics, researchers identified twice as many risk variants for bipolar disorder as have been reported so far. In the largest genetic study to date of bipolar disorder, researchers from around the world have identified 64 areas of the human genome with DNA variations that increase the risk of bipolar disorder. This is more than twice as many regions as previously identified. The research group also found a genetic overlap between bipolar disorder and other psychiatric disorders. The results of the research were published on May 17 in the journal Nature Genetics. The study was carried out by a large research team in the international collaborative project "Psychiatric Genomics Consortium", where several researchers in Norway contribute and are led from the NORMENT center. To study the underlying biology of bipolar disorder, the researchers analyzed the entire human genetic material through a so-called 'genomic association study'. This involves mapping the gene variants of a large number of people and looking for genetic variants that occur more frequently in disease. In total, the researchers examined more than 7.5 million gene variants in almost 415,000 people, of which 40,000 had bipolar disorder. The study revealed 64 regions with DNA variations that increase the risk of bipolar disorder. It is well known that genes and heredity play an important role in bipolar disorder. By identifying DNA variations that increase the risk of disease, we can gain insight into the underlying biology of bipolar disorder. We found, among other things, that gene variants that are involved in communication between nerve cells, and especially signal transmission depending on calcium, increase the risk of developing bipolar disorder. This may indicate that drugs that block calcium channels in the brain, and which are already used to treat, among other things, high blood pressure, may have a potential treatment effect in bipolar disorder. The researchers also demonstrated an overlap between gene variants for bipolar disorder and other psychiatric disorders. In addition, the results indicated different genetic subgroups of bipolar disorder. The researchers found a large genetic similarity between bipolar disorder type 1 and schizophrenia, while bipolar disorder type 2 was more genetically similar to major depression. The study also found a genetic link between bipolar disorder and sleep habits, and with the use of alcohol and drugs. Bipolar disorder is a complex psychiatric disorder that is characterized by recurrent periods of mania / hypomania and depression. With bipolar disorder type 1 you have mania, with type 2 hypomania. The disorder affects up to 50 million people worldwide, usually occurs in early adulthood, often has a chronic course and carries an increased risk of suicide. Bipolar disorder is therefore a major public health problem and a major cause of disability worldwide. This study of hundreds of thousands of DNA sequences would not have been possible without extensive collaboration between researchers from around the world. Through this work, we identified some specific genes and DNA variations that can now be followed up in laboratory experiments, so that we can better understand the biological mechanisms involved in bipolar disorder.

Ny kunnskap om arvelige faktorer ved psykiske lidelser. Ny kompetanse på statistiske metoder og stor-data analyser.

Psychiatric disorders are recognized as leading causes of morbidity globally, and are among the most costly disorders to affect humans. Identifying the underlying pathophysiology is imperative and can lead to major health benefits, through better treatment and prevention strategies. The heritabiilty is high, but most of the genetic factors are unknown. The current project combines analytical results from Norwegian human biobank material and data from health registries, surveys and services to develop knowledge about genetic risk factors and causes, to identify the underlying disease mechanisms of psychiatric disorders, which are complex human diseases. We have genotypes from n=80 000 Norwegians, which will be used for discovery of rare variants together with Nordic partners, and collaborate with international samples including genotype analysis of 2.4 mill people. The project is based on multidisciplinary collaboration between Norwegian universities, hospitals and the Institute of Public Health. Further, it builds on strong biostatistical and bioinformatics competence and will increase the capacity in this field in Norway, in line with the research strategy. The project is made possible through a tight collaboration between strong research groups, which are leaders in bioinformatics and biostatistics fields in Norway. They have complementary expertise leading to synergy, and the team is closely integrated with large, international networks. The project will facilitate the development of excellent research environments, with a long-term potential for future studies based on Norwegian advantages, the human biobank material and registry datasets. Although the project focuses on psychiatric disorders, the methods and infrastructure can be used for other complex human diseases, and for more samples from additional studies. The expertise will be disseminated by training and courses, and infrastructure and data will be made available to other researchers.