Global Gene-Expression in Psychiatric Illnesses

Written by Ashima Seth and Edited by Myra Ali

With increasing awareness about psychiatric illnesses, it has come to light that the number of people suffering from such conditions is truly staggering. According to the National Alliance on Mental Illness (NAMI), one in five adults encounters a mental illness every year, and a majority of the symptoms appear between the ages of 14 and 24 [1]. With such a large amount of individuals facing crippling symptoms, it is not surprising to see a recent surge in research studies that are attempting to better understand and diagnose psychiatric illnesses, as well as their roots in one’s environment and genetics [2]. One study by UCLA (University of California, Los Angeles) explores the shared molecular pathology across some major psychiatric disorders [3]. It is well-known among the biomedical community that some individuals are at a higher risk of suffering from mental illnesses than others, due to a genetic predisposition. However, while studying the DNA of such individuals would help us better understand the genes that cause such predisposition, it would not help in understanding the expression of these genes. Hence, the UCLA research team chose to instead study the RNA expressed from these genes for a molecular profile of psychiatric illnesses [4].

The research team first collected brain tissue samples from several deceased individuals, 331 of which were samples from people who suffered from any of the five major psychiatric illnesses: Autism, Schizophrenia, Bipolar Disorder, Alcoholism and Depression. Additionally, 381 of these brain tissue samples were used to serve as a control group for comparison. In their study, all data were scrutinized using normalization and strict quality control to account for possible confounders and covariates. Through statistical analysis of the brain tissue samples, the study found a significant overlap in the expression of RNA from genes of Autism Spectrum Disorder (ASD), Schizophrenia and Major Depressive Disorder. The researchers then corrected the data for potential outliers, and validated that their results from this gene expression study could be reproduced in other studies by comparing their data to independent RNA sequences.

This research study was instrumental in determining that ASD, Schizophrenia, and Depression share patterns of gene expression. The results from this study has many implications for the biomedical community. First, by determining the genetic basis for the three psychiatric illnesses involved, this study helped to open up a pathway for potentially diagnosing patients based on their gene-expression patterns. Although this would be an expensive process initially, technological advancements would soon make it a viable option. Second, by determining that there is an overlap in molecular expression for ASD, Schizophrenia and Depression, this research has the potential to change how these diseases are understood, recognized, and possibly even treated by the medical community. Last, but not the least, this research paves the way for further studies because although it helped determine the consequences of this shared expressivity, the mechanism by which this expression is activated is yet to be understood. In the future, this understanding could prove to be crucial in modifying the activation mechanism behind these diseases as a way to cure psychiatric illnesses.

References:

1. “You Can’t Always See an Eating Disorder.” NAMI: National Alliance on Mental Illness, www.nami.org/Learn-More/Mental-Health-Conditions.
2. “Genetic Factors and Mental Disorders.” Encyclopedia of Mental Disorders, www.minddisorders.com/Flu-Inv/Genetic-factors-and-mental-disorders.html.
3. Gandal, M.J., Haney, J.R., Parikshak, N.N., Leppa V., Ramaswami, G., Hartl, C., Schork, A.J., Appadurai, V., Buil, A., Werge, T.M., Liu, C., White, K.P., CommonMind Consortium, PsychENCODE Consortium, iPSYCH-BROAD Working Group, Horvath, S., Geschwind, D.H. 2018. Shared molecular neuropathology across major psychiatric disorders parallels polygenic overlap. Science. 359: 693-697.
4. “Autism, Schizophrenia, Bipolar Disorder Share Molecular Traits, Study Finds.” ScienceDaily, ScienceDaily, 8 Feb. 2018, www.sciencedaily.com/releases/2018/02/180208141346.htm.