Objective: To perform a meta-analysis of all published genetic association studies of NRNX1 variants and psychotic spectrum disorders (PSD).
Methods: Potential studies were identified through PubMed/MEDLINE, EMBASE, HuGeNet, GeneCard and WoS up from 1980 until June 2015 (week 5). Published observational studies reporting NRXN1 variants in PSD cases and in non-PSD controls were all considered eligible for inclusion in this systematic review. Two reviewers selected studies for possible inclusion and extracted data independently following a standardized protocol. Different meta-analyses were performed for each NRXN1 variant and PSD and controls, with a random-effect model to calculate the pooled OR and its corresponding 95% CI. Forest plots and Cochran’s Q-Statistic and I2 index were calculated to check for heterogeneity. Subgroup analyses and chi-square test were carried out to analyze potential moderators. Publication bias and quality of reporting were also analyzed.
Results: 19 studies met our inclusion criteria, providing a total sample of 25208 patients with PSD and 56971 controls. Meta-analyses of NRXN1 deletions (OR = 3.36), exons (OR = 3.53) and introns (OR = 2.02) showed evidence of an association between NRXN1 gene and PSD. Only one study influed in a meta-analysis (NRXN1 deletions) and no quality criterion affected as moderating variable. There was evidence of potential publication bias in NRXN1 deletions, exonic and promoter meta-analyses.
Conclusions: We found association between some variants of the NRXN1 gene and PSD. It´s important to develop a greater effort for the study of the NRXN1 gene and bigger number of studies that will clarify it´s association.
The appendix is in Spanish.
Table of Contents
Abstract
Background
Methods
Search strategy
Inclusion and exclusion criteria
Data extraction
Quality of the studies
Statistical analysis
Results
Meta-analysis of association of the NRXN1 variants with PSD
Sensitivity analysis
Quality of studies
Publication bias
NRXN1 deletions
NRXN1 duplications
NRXN1 polimorphisms
NRXN1 coding region (exon)
NRXN1 no coding region (intron)
NRXN1 promoter region
Discussion
Conclusions
References
Supplementary Matherial
Supplementary Figures
Supplementary Tables
Appendix
I. Introducción
II. Variables
III. Análisis unitario
IV. Explicación de variables
V. Variables de sujeto
VI. Variables de la enfermedad
VII. Características del marcador genético
VIII. Variables metodológicas
IX. Variables resultado
Research Objectives and Themes
This study aims to perform a comprehensive meta-analysis of all published genetic association studies investigating the relationship between NRXN1 variants and psychotic spectrum disorders (PSD). By synthesizing data from existing observational research, the work seeks to clarify the role of various genetic alterations within the NRXN1 gene in the susceptibility to these psychiatric conditions.
- Systematic identification and evaluation of genetic association studies regarding NRXN1 variants and PSD.
- Assessment of specific genetic alteration types, including deletions, duplications, and polymorphisms.
- Analysis of the impact of different gene regions (coding, non-coding, and promoter) on PSD susceptibility.
- Evaluation of potential publication bias and methodological quality across included studies.
- Exploration of the "common disease / common variant" model in the context of NRXN1 and psychiatric disorders.
Excerpt from the Book
Discussion
To our knowledge, this is the first meta-analysis performed that analyzes the association between variants of the NRXN1 gene and PSD. We obtained global odds ratios ranging from 1.16 - 4.39 and the results suggest a statistically significant association for the deletions, the coding region (exon) and the non-coding region (intron). However, no association has been demonstrated for the remaining alterations or genetic areas (insertions, duplications, genetic polimorphisms and promoter area).
NRXN1 deletions were significantly associated with psychotic disorders with a OR = 3.36 (95% CI = 2.07, 5.46). The same happens with the coding or exon region of the gene (OR = 3.53, 95% CI = 1.58, 7.86) and the region that does not coding or intronic (OR = 2.02, 95% CI = 1.10, 3.69). It is important to note that individual studies with small sample sizes probably do not have sufficient statistical power to detect the effect that has been found in this meta-analysis.
Summary of Chapters
Abstract: Provides a high-level summary of the meta-analysis objectives, methodology, key findings regarding NRXN1 associations with PSD, and conclusions.
Background: Introduces the clinical context of schizophrenia and psychotic disorders, the role of synaptic connectivity, and the theoretical genetic models linking NRXN1 to neurocognitive disorders.
Methods: Details the search strategy, inclusion and exclusion criteria, protocols for data extraction, quality assessment of studies, and the statistical methods used for meta-analysis and bias detection.
Results: Presents the findings of the systematic search, flow chart of study selection, and the meta-analytical outcomes for various NRXN1 variants and gene regions.
Discussion: Interprets the findings in relation to current scientific literature, discusses limitations such as publication bias and sample size, and reflects on the complexity of psychiatric diagnostics.
Conclusions: Summarizes the evidence linking specific NRXN1 mutations to psychotic phenotypes and emphasizes the need for further basic and clinical research.
Keywords
NRXN1, neurexin 1, 2p16.3, meta-analysis, schizophrenia, psychotic disorder, schizoaffective disorder, psychosis, genetic association, CNV, deletions, exons, introns, gene variants, synaptic connectivity.
Frequently Asked Questions
What is the primary focus of this research?
The paper focuses on identifying the genetic association between variations in the NRXN1 gene and the risk of developing psychotic spectrum disorders (PSD).
What are the central themes discussed in the work?
The work covers the biological function of neurexin 1, the impact of various types of genetic mutations (deletions, duplications, etc.), and the methodology of conducting a systematic meta-analysis of clinical genetic data.
What is the primary research question?
The primary research question is whether specific structural and sequence variations within the NRXN1 gene are statistically associated with an increased risk of psychotic spectrum disorders.
Which scientific methodology is applied?
The researchers conducted a systematic review and meta-analysis, employing random-effects models, forest plots, and statistical tests like Cochran’s Q-statistic and Egger’s test to assess effect sizes and publication bias.
What is covered in the main body of the text?
The main body covers the identification of eligible observational studies, the extraction of genotype data, the quality evaluation of these studies, and the resulting meta-analytical calculations regarding OR (odds ratio) values for different NRXN1 alterations.
Which keywords characterize this meta-analysis?
Key terms include NRXN1, meta-analysis, schizophrenia, psychotic disorders, genetic association, and synaptic transmission.
How does the study address the publication bias?
The study utilizes the 'trim-and-fill' method and Egger's test to investigate and account for potential publication bias, especially where smaller studies might be missing from the literature.
Why are the exon and intron regions of the NRXN1 gene specifically analyzed?
These regions were analyzed because structural alterations in them, such as deletions, have been historically implicated in synaptic dysfunction and are frequent enough in the datasets to allow for meta-analytical comparison.
What conclusion does the author reach regarding the "common disease / common variant" model?
The author suggests that the "common disease / common variant" (CDCV) model is a suitable theoretical framework for understanding how common genetic variants in the general population might confer a relative risk for PSD in relation to NRXN1.
- Quote paper
- Pedro Gurillo Muñoz (Author), 2017, Meta-analysis of the association of NRXN1 variants and Psychotic Spectrum Disorders, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/439368
