Exonic DNA sequencing of ERBB4 in bipolar disorder

Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.
PLoS ONE (Impact Factor: 3.23). 05/2011; 6(5):e20242. DOI: 10.1371/journal.pone.0020242
Source: PubMed


The Neuregulin-ErbB4 pathway plays a crucial role in brain development and constitutes one of the most biologically plausible signaling pathways implicated in schizophrenia and, to a lesser extent, in bipolar disorder (BP). However, recent genome-wide association analyses have not provided evidence for common variation in NRG1 or ERBB4 influencing schizophrenia or bipolar disorder susceptibility. In this study, we investigate the role of rare coding variants in ERBB4 in BP cases with mood-incongruent psychotic features, a form of BP with arguably the greatest phenotypic overlap with schizophrenia. We performed Sanger sequencing of all 28 exons in ERBB4, as well as part of the promoter and part of the 3'UTR sequence, hypothesizing that rare deleterious variants would be found in 188 cases with mood-incongruent psychosis from the GAIN BP study. We found 42 variants, of which 16 were novel, although none were non-synonymous or clearly deleterious. One of the novel variants, present in 11.2% of cases, is located next to an alternative stop codon, which is associated with a shortened transcript of ERBB4 that is not translated. We genotyped this variant in the GAIN BP case-control samples and found a marginally significant association with mood-incongruent psychotic BP compared with controls (additive model: OR = 1.64, P-value = 0.055; dominant model: OR = 1.73. P-value = 0.039). In conclusion, we found no rare variants of clear deleterious effect, but did uncover a modestly associated novel variant that could affect alternative splicing of ERBB4. However, the modest sample size in this study cannot definitively rule out a role for rare variants in bipolar disorder and studies with larger sample sizes are needed to confirm the observed association.

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Available from: Michael A Rongione, Oct 04, 2015
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    • "The latter is currently the least expensive and a highly reliable alternative to WGS in uncovering genetic defects associated with various complex traits, particularly when combined with sequencing exome flanking non-coding regions [8,9]. Sanger sequencing of these additional regions has also shown their significance [10]. Some genetic variants will be absent or underrepresented using this approach, since approximately 15% of patients with a genetically predisposed condition do not have coding sequence mutations [5]. "
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    ABSTRACT: Background Next Generation Sequencing (NGS) is expected to help find the elusive, causative genetic defects associated with Bipolar Disorder (BD). This article identifies the importance of NGS and further analyses the social and ethical implications of this approach when used in research projects studying BD, as well as other psychiatric ailments, with a view to ensuring the protection of research participants. Methods We performed a systematic review of studies through PubMed, followed by a manual search through the titles and abstracts of original articles, including the reviews, commentaries and letters published in the last five years and dealing with the ethical and social issues raised by NGS technologies and genomics studies of mental disorders, especially BD. A total of 217 studies contributed to identify the themes discussed herein. Results The amount of information generated by NGS renders individuals suffering from BD particularly vulnerable, and increases the need for educational support throughout the consent process, and, subsequently, of genetic counselling, when communicating individual research results and incidental findings to them. Our results highlight the importance and difficulty of respecting participants’ autonomy while avoiding any therapeutic misconception. We also analysed the need for specific regulations on the use and communication of incidental findings, as well as the increasing influence of NGS in health care. Conclusions Shared efforts on the part of researchers and their institutions, Research Ethics Boards as well as participants’ representatives are needed to delineate a tailored consent process so as to better protect research participants. However, health care professionals involved in BD care and treatment need to first determine the scientific validity and clinical utility of NGS-generated findings, and thereafter their prevention and treatment significance.
    BMC Medical Ethics 12/2012; 13(1):36. DOI:10.1186/1472-6939-13-36 · 1.50 Impact Factor
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    ABSTRACT: Neuregulins (NRGs) are signaling molecules involved in various cellular and developmental processes. Abnormal expression and (or) genomic variations of some of these molecules, such as NRG1, have been associated with disease conditions such as cancer and schizophrenia. To gain a comprehensive molecular insight into possible pathways/networks regulated by NRG1-alpha, we performed a global expression profiling analysis on lymphoblastoid cell lines exposed to NRG1-alpha. Our data show that this signaling molecule mainly regulates coordinated expression of genes involved in three processes: phosphorylation, acetylation, and alternative splicing. These processes have fundamental roles in proper development and function of various tissues including the central nervous system (CNS)-a fact that may explain conditions associated with NRG1 dysregulations such as schizophrenia. The data also suggest NRG1-alpha regulates genes (FBXO41) and miRNAs (miR-33) involved in cholesterol metabolism. Moreover, RPN2, a gene already shown to be dysregulated in breast cancer cells, is also differentially regulated by NRG1-alpha treatment.
    Genome 10/2013; 56(10):619-25. DOI:10.1139/gen-2013-0068 · 1.42 Impact Factor
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    ABSTRACT: Genetic variations in ERBB4 were associated with increased susceptibility for schizophrenia (SCZ) and bipolar disorders (BPD). Structural imaging studies showed cortical abnormalities in adolescents and adults with SCZ or BPD. However, less is known about subclinical cortical changes or the influence of ERBB4 on cortical development. 971 healthy children (ages 3-20 years old; 462 girls and 509 boys) were genotyped for the ERBB4-rs7598440 variants, had structural MRI, and cognitive evaluation (NIH Toolbox ®). We investigated the effects of ERBB4 variants and family history of SCZ and/or BPD (FH) on cortical measures and cognitive performances across ages 3-20 years using a general additive model. Variations in ERBB4 and FH impact differentially the age-related cortical changes in regions often affected by SCZ and BPD. The ERBB4-TT-risk genotype children with no FH had subtle cortical changes across the age span, primarily located in the left temporal lobe and superior parietal cortex. In contrast, the TT-risk genotype children with FH had more pronounced age-related changes, mainly in the frontal lobes compared to the non-risk genotype children. Interactive effects of age, FH and ERBB4 variations were also found on episodic memory and working memory, which are often impaired in SCZ and BPD. Healthy children carrying the risk-genotype in ERBB4 and/or with FH had cortical measures resembling those reported in SCZ or BPD. These subclinical cortical variations may provide early indicators for increased risk of psychiatric disorders and improve our understanding of the effect of the NRG1-ERBB4 pathway on brain development.
    Brain Imaging and Behavior 03/2015; 9(1). DOI:10.1007/s11682-015-9363-y · 4.60 Impact Factor