About this Research Topic
Recent large genome-wide association studies (GWAS) have highlighted both a) the polygenic architecture of each of psychiatric disorders, such as posttraumatic stress disorder (PTSD), schizophrenia (SCZ), major depression disorder (MDD), bipolar disorders (BD) and b) their overlapping genetic risk factors. Each of these disorders has also shown some degree of overlapping with autoimmune diseases (e.g. diabetes, asthma), with one of the most significant loci in the GWAS -SCZ found on chromosome 6 within the HLA locus, or other medical disorders and traits. Furthermore, genetic associations using Mendelian randomization models have revealed a causality of effects between genetically determined female body shape and the genetic risk for PTSD. The correlation among these disorders, including pleiotropy, causality, synergisms, temporality, or mediation is not completely understood.
A nosological characterization of major mental health syndromes, such as SCZ, BD, and MDD, arose based on their symptom patterns and course of illness. However, doubts remain about the degree of overlap of these disorders, and if they could really be categorized as entirely distinct entities. Family studies have also shown that some of these disorders, such as SCZ and BD, partially share common genetic risks, challenging their diagnostic classification. Identifying pleiotropic mechanisms, which may be responsible for these different symptom patterns, could facilitate the understanding of these psychiatric disorders.
In addition, it is imperative to distinguish unique genetic risk factors for specific disorders from those correlated to other traits/diseases. Indeed, the detection of pleiotropic effects may shed light on the underlying biology and allow a potential repurposing of the use of existing drugs; on the other hand, identifying unique genes associated with one trait may speed the development of targeted therapies. Furthermore, recent research has shown that a unique genetic signature may help identify distinct diagnosis category: specific genes uniquely implicated in suicidal behaviors (SB), rather than psychiatric diagnoses, have enabled to support a proposal of creating a comprehensive diagnostic category of SB, which can identify susceptible individuals regardless of coexisting psychiatric disorders.
In recent years, large genome-wide association studies have been extremely helpful to identify new genetic risks of psychiatric diseases (e.g. PTSD, SCZ, BP, MDD), and genetic overlapping risks among these disorders and other medical diseases, and traits. A more comprehensive understanding of the genetic overlapping among these disorders is needed to clarify common pathways among diseases, or specific genes uniquely implicated in each disorder. This issue will emphasize reports focusing on genetic psychiatric disorders and their overlapping risks with other traits. These articles could include genetic articles, statistical methodological reports who evaluate pleiotropy, synergism, etc, among psychiatric disorders and other traits, and reviews. The general purpose will be to identify common genes and pathways among different psychiatric disorders and medical diseases and traits, along with unique gene signatures. Areas to be covered in this Research Topic may include, but are not limited to:
• Psychiatric Diseases and their overlapping genetic risks
• Autoimmune diseases and their involvement in psychiatric disorders
• Pleiotropy of psychiatric disorders
• Infectious diseases and their association with psychiatric diseases
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