A team, led by Trinity researchers, have discovered a shared genetic origin for Amyotrophic Lateral Sclerosis (ALS), also known as Motor Neurone Disease (MND), and schizophrenia. The study indicates for the first time that there is biological causative link between these two diverse conditions. Research into the genetic causes of schizophrenia and similar conditions in psychiatry has been problematic, due to the multiple contributing genetic and non-genetic factors. Published in the prestigious Nature Communications journal this week, the research paper announces that these new findings will have major implications regarding the ways in which diseases are classified.
Almost 13,000 cases of ALS/MND, and over 30,000 schizophrenia cases, were analysed in an extensive genome-wide association study of over 100,000 unique individuals conducted by Trinity researchers. This study came to the conclusion that many of the genes linked to the causation of these two very different syndromes are the same. The study showed, using linkage disequilibrium score regression, that there is an estimated genetic correlation between ALS and schizophrenia of 14.3%. This means that there is an overlap of 14% in genetic susceptibility to the adult onset neuro-degeneration condition ALS/MND and the developmental neuropsychiatric disorder schizophrenia.
This research builds on prior work investigating linkages between schizophrenia and other neuropsychiatric conditions including bipolar affective disorder and autism. However, this is the first time that a genetic overlap between the non-psychiatric ALS/MND and any psychiatric condition has been found.
Dr Russell McLaughlin, Ussher Assistant Professor in Genome Analysis at Trinity College Dublin, was the lead author of the paper. In a statement, he explained: “While neurological and psychiatric conditions may have very different characteristics and clinical presentations, our work has shown that the biological pathways that lead to these diverse conditions have much in common.”
Another Trinity professor, Orla Hardiman, was the senior author and lead investigator in the project and is currently Professor of Neurology and Consultant Neurologist at the National Neuroscience Centre. She stated: “Instead of thinking of ALS/MND as a degeneration of one cell at a time, we should think about ALS/MND in the same way that we think about schizophrenia, which is a problem of disruptions in connectivity between different regions of the brain.” The existing divide between neurology and psychiatry can be a barrier to understanding, a divide which the researchers claims to challenge. Professor Hardiman describes that “the other significant issue that this research brings up is that the divide between psychiatry and neurology is a false one,” and that “we need to recognise that brain disease has many different manifestations”.
The Trinity group, along with their partners in the University of Utrecht, will continue to study the links between ALS/MND and psychiatric conditions.
