High-impact rare genetic variants in severe schizophrenia

2021 ◽  
Vol 118 (51) ◽  
pp. e2112560118
Author(s):  
Anthony W. Zoghbi ◽  
Ryan S. Dhindsa ◽  
Terry E. Goldberg ◽  
Aydan Mehralizade ◽  
Joshua E. Motelow ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Odds Ratio ◽  
High Impact ◽  
Psychiatric Genetics ◽  
Loss Of Function ◽  
Treatment Resistant ◽  
Complex Disorders ◽  
Extreme Phenotype ◽  
Case Selection ◽  
Rare Genetic Variants

Extreme phenotype sequencing has led to the identification of high-impact rare genetic variants for many complex disorders but has not been applied to studies of severe schizophrenia. We sequenced 112 individuals with severe, extremely treatment-resistant schizophrenia, 218 individuals with typical schizophrenia, and 4,929 controls. We compared the burden of rare, damaging missense and loss-of-function variants between severe, extremely treatment-resistant schizophrenia, typical schizophrenia, and controls across mutation intolerant genes. Individuals with severe, extremely treatment-resistant schizophrenia had a high burden of rare loss-of-function (odds ratio, 1.91; 95% CI, 1.39 to 2.63; P = 7.8 × 10−5) and damaging missense variants in intolerant genes (odds ratio, 2.90; 95% CI, 2.02 to 4.15; P = 3.2 × 10−9). A total of 48.2% of individuals with severe, extremely treatment-resistant schizophrenia carried at least one rare, damaging missense or loss-of-function variant in intolerant genes compared to 29.8% of typical schizophrenia individuals (odds ratio, 2.18; 95% CI, 1.33 to 3.60; P = 1.6 × 10−3) and 25.4% of controls (odds ratio, 2.74; 95% CI, 1.85 to 4.06; P = 2.9 × 10−7). Restricting to genes previously associated with schizophrenia risk strengthened the enrichment with 8.9% of individuals with severe, extremely treatment-resistant schizophrenia carrying a damaging missense or loss-of-function variant compared to 2.3% of typical schizophrenia (odds ratio, 5.48; 95% CI, 1.52 to 19.74; P = 0.02) and 1.6% of controls (odds ratio, 5.82; 95% CI, 3.00 to 11.28; P = 2.6 × 10−8). These results demonstrate the power of extreme phenotype case selection in psychiatric genetics and an approach to augment schizophrenia gene discovery efforts.

scholarly journals Exome sequencing identifies novel AD-associated genes.

2020 ◽  
Author(s):  
Henne Holstege ◽  
Marc Hulsman ◽  
Camille Charbonnier ◽  
Benjamin Grenier-Boley ◽  
Olivier Quenez ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Genetic Variants ◽  
Rare Variants ◽  
Mendelian Inheritance ◽  
Loss Of Function ◽  
App Processing ◽  
Complex Disorders ◽  
Pathogenic Variants ◽  
Increased Risk ◽  
The Impact

Background: With the development of next-generation sequencing technologies, it is possible to identify rare genetic variants that influence the risk of complex disorders. To date, whole exome sequencing (WES) strategies have shown that specific clusters of damaging rare variants in the TREM2, SORL1 and ABCA7 genes are associated with an increased risk of developing Alzheimers Disease (AD), reaching odds ratios comparable with the APOE-ε4 allele, the main common AD genetic risk factor. Here, we set out to identify additional AD-associated genes by an exome-wide investigation of the burden of rare damaging variants in the genomes of AD cases and cognitively healthy controls. Method: We integrated the data from 25,982 samples from the European ADES consortium and the American ADSP consortium. We developed new techniques to homogenise and analyse these data. Carriers of pathogenic variants in genes associated with Mendelian inheritance of dementia were excluded. After quality control, we used 12,652 AD cases and 8,693 controls for analysis. Genes were analysed using a burden analysis, including both non-synonymous and loss-of-function rare variants, the impact of which was prioritised using REVEL. Result: We confirmed that carrying rare protein-damaging genetic variants in TREM2, SORL1 or ABCA7 is associated with increased AD-risk. Moreover, we found that carrying rare damaging variants in the microglial ATP8B4 gene was significantly associated with AD, and we found suggestive evidence that rare variants in ADAM10, ABCA1, ORC6, B3GNT4 and SRC genes associated with increased AD risk. High-impact variants in these genes were mostly extremely rare and enriched in AD patients with earlier ages at onset. Additionally, we identified two suggestive protective associations in CBX3 and PRSS3. We are currently replicating these associations in independent datasets. Conclusion: With our newly developed homogenisation methods, we identified novel genetic determinants of AD which provide further evidence for a pivotal role of APP processing, lipid metabolism, and microglia and neuro-inflammatory processes in AD pathophysiology.

scholarly journals Two-Stage Extreme Phenotype Sequencing Design for Discovering and Testing Common and Rare Genetic Variants: Efficiency and Power

2012 ◽  
Vol 73 (3) ◽  
pp. 139-147 ◽  
Author(s):  
Guolian Kang ◽  
Dongyu Lin ◽  
Hakon Hakonarson ◽  
Jinbo Chen
Keyword(s):  
Genetic Variants ◽  
Two Stage ◽  
Extreme Phenotype ◽  
Rare Genetic Variants

scholarly journals Rare Pathogenic Variants in Mitochondrial and Inflammation-Associated Genes May Lead to Inflammatory Cardiomyopathy in Chagas Disease

2021 ◽  
Author(s):  
Maryem Ouarhache ◽  
Sandrine Marquet ◽  
Amanda Farage Frade ◽  
Ariela Mota Ferreira ◽  
Barbara Ianni ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Chagas Disease ◽  
Genetic Variants ◽  
Interferon Γ ◽  
Loss Of Function ◽  
Inflammatory Cardiomyopathy ◽  
Pathogenic Variants ◽  
Rare Genetic Variants ◽  
Ifn Γ ◽  
Genetically Determined

Abstract Abstract Cardiomyopathies are an important cause of heart failure and sudden cardiac death. Little is known about the role of rare genetic variants in inflammatory cardiomyopathy. Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory cardiomyopathy prevalent in Latin America, developing in 30% of the 6 million patients chronically infected by the protozoan Trypanosoma cruzi, while 60% remain free of heart disease (asymptomatic (ASY)). The cytokine interferon-γ and mitochondrial dysfunction are known to play a major pathogenetic role. Chagas disease provides a unique model to probe for genetic variants involved in inflammatory cardiomyopathy. Methods We used whole exome sequencing to study nuclear families containing multiple cases of Chagas disease. We searched for rare pathogenic variants shared by all family members with CCC but absent in infected ASY siblings and in unrelated ASY. Results We identified heterozygous, pathogenic variants linked to CCC in all tested families on 22 distinct genes, from which 20 were mitochondrial or inflammation-related – most of the latter involved in proinflammatory cytokine production. Significantly, incubation with IFN-γ on a human cardiomyocyte line treated with an inhibitor of dihydroorotate dehydrogenase brequinar (enzyme showing a loss-of-function variant in one family) markedly reduced mitochondrial membrane potential (ΔψM), indicating mitochondrial dysfunction. Conclusion Mitochondrial dysfunction and inflammation may be genetically determined in CCC, driven by rare genetic variants. We hypothesize that CCC-linked genetic variants increase mitochondrial susceptibility to IFN-γ-induced damage in the myocardium, leading to the cardiomyopathy phenotype in Chagas disease. This mechanism may also be operative in other inflammatory cardiomyopathies.

scholarly journals Putative second hit rare genetic variants in families with seemingly GBA-associated Parkinson’s disease

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Muhammad Aslam ◽  
Nirosiya Kandasamy ◽  
Anwar Ullah ◽  
Nagarajan Paramasivam ◽  
Mehmet Ali Öztürk ◽  
...  
Keyword(s):  
Risk Factors ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Genetic Variants ◽  
Rare Variants ◽  
Alpha Synuclein ◽  
Younger Age ◽  
Targeted Treatments ◽  
Genes Encoding ◽  
Rare Genetic Variants

AbstractRare variants in the beta-glucocerebrosidase gene (GBA1) are common genetic risk factors for alpha synucleinopathy, which often manifests clinically as GBA-associated Parkinson’s disease (GBA-PD). Clinically, GBA-PD closely mimics idiopathic PD, but it may present at a younger age and often aggregates in families. Most carriers of GBA variants are, however, asymptomatic. Moreover, symptomatic PD patients without GBA variant have been reported in families with seemingly GBA-PD. These observations obscure the link between GBA variants and PD pathogenesis and point towards a role for unidentified additional genetic and/or environmental risk factors or second hits in GBA-PD. In this study, we explored whether rare genetic variants may be additional risk factors for PD in two families segregating the PD-associated GBA1 variants c.115+1G>A (ClinVar ID: 93445) and p.L444P (ClinVar ID: 4288). Our analysis identified rare genetic variants of the HSP70 co-chaperone DnaJ homolog subfamily B member 6 (DNAJB6) and lysosomal protein prosaposin (PSAP) as additional factors possibly influencing PD risk in the two families. In comparison to the wild-type proteins, variant DNAJB6 and PSAP proteins show altered functions in the context of cellular alpha-synuclein homeostasis when expressed in reporter cells. Furthermore, the segregation pattern of the rare variants in the genes encoding DNAJB6 and PSAP indicated a possible association with PD in the respective families. The occurrence of second hits or additional PD cosegregating rare variants has important implications for genetic counseling in PD families with GBA1 variant carriers and for the selection of PD patients for GBA targeted treatments.

scholarly journals Clinical and genetic spectrum of glycogen storage disease in Iranian population using targeted gene sequencing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zahra Beyzaei ◽  
Fatih Ezgu ◽  
Bita Geramizadeh ◽  
Mohammad Hadi Imanieh ◽  
Mahmood Haghighat ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Molecular Genetic ◽  
Gene Sequencing ◽  
Glycogen Storage ◽  
Loss Of Function ◽  
Retrospective Case ◽  
Complex Disorders ◽  
Glycogen Storage Diseases ◽  
Targeted Gene Sequencing ◽  
Retrospective Case Study

AbstractGlycogen storage diseases (GSDs) are known as complex disorders with overlapping manifestations. These features also preclude a specific clinical diagnosis, requiring more accurate paraclinical tests. To evaluate the patients with particular diagnosis features characterizing GSD, an observational retrospective case study was designed by performing a targeted gene sequencing (TGS) for accurate subtyping. A total of the 15 pediatric patients were admitted to our hospital and referred for molecular genetic testing using TGS. Eight genes namely SLC37A4, AGL, GBE1, PYGL, PHKB, PGAM2, and PRKAG2 were detected to be responsible for the onset of the clinical symptoms. A total number of 15 variants were identified i.e. mostly loss-of-function (LoF) variants, of which 10 variants were novel. Finally, diagnosis of GSD types Ib, III, IV, VI, IXb, IXc, X, and GSD of the heart, lethal congenital was made in 13 out of the 14 patients. Notably, GSD-IX and GSD of the heart-lethal congenital (i.e. PRKAG2 deficiency) patients have been reported in Iran for the first time which shown the development of liver cirrhosis with novel variants. These results showed that TGS, in combination with clinical, biochemical, and pathological hallmarks, could provide accurate and high-throughput results for diagnosing and sub-typing GSD and related diseases.

Has the time come to integrate genetic risk scores into clinical practice?

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F.V Moniz Mendonca ◽  
M.I Mendonca ◽  
A Pereira ◽  
J Monteiro ◽  
J Sousa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Clinical Practice ◽  
Genetic Variants ◽  
Genetic Risk ◽  
Odds Ratio ◽  
Risk Scores ◽  
Cumulative Number ◽  
Genetic Risk Scores ◽  
Risk Alleles ◽  
Cad Risk

Abstract Background The risk for Coronary Artery Disease (CAD) is determined by both genetic and environmental factors, as well as by the interaction between them. It is estimated that genetic factors could account for 40% to 55% of the existing variability among the population (inheritability). Therefore, some authors have advised that it is time we integrated genetic risk scores into clinical practice. Aim The aim of this study was to evaluate the magnitude of the association between an additive genetic risk score (aGRS) and CAD based on the cumulative number of risk alleles in these variants, and to estimate whether their use is valuable in clinical practice. Methods A case-control study was performed in a Portuguese population. We enrolled 3120 participants, of whom 1687 were CAD patients and 1433 were normal controls. Controls were paired to cases with respect to gender and age. 33 genetic variants known to be associated with CAD were selected, and an aGRS was calculated for each individual. The aGRS was further subdivided into deciles groups, in order to estimate the CAD risk in each decile, defined by the number of risk alleles. The magnitude of the risk (odds ratio) was calculated for each group by multiple logistic regression using the 5th decile as the reference group (median). In order to evaluate the ability of the aGRS to discriminate susceptibility to CAD, two genetic models were performed, the first with traditional risk factors (TRF) and second with TRF plus aGRS. The AUC of the two ROC curves was calculated. Results A higher prevalence of cases over controls became apparent from the 6th decile of the aGRS, reflecting the higher number of risk alleles present (see figure). The difference in CAD risk was only significant from the 6th decile, increasing gradually until the 10th decile. The odds ratio (OR) for the last decile related to 5th decile (median) was 1.87 (95% CI:1.36–2.56; p<0.0001). The first model yielded an AUC=0.738 (95% CI:0.720–0.755) and the second model was slightly more discriminative for CAD risk (AUC=0.748; 95% CI:0.730–0.765). The DeLong test was significant (p=0.0002). Conclusion Adding an aGRS to the non-genetic risk factors resulted in a modest improvement in the ability to discriminate the risk of CAD. Such improvement, even if statistically significant, does not appear to be of real value in clinical practice yet. We anticipate that with the development of further knowledge about different SNPs and their complex interactions, and with the inclusion of rare genetic variants, genetic risk scores will be better suited for use in a clinical setting. Funding Acknowledgement Type of funding source: None

Contribution of rare genetic variants to drug response in absence epilepsy

2021 ◽  
Vol 170 ◽  
pp. 106537
Author(s):  
Kenneth A. Myers ◽  
Mark F. Bennett ◽  
Bronwyn E. Grinton ◽  
Gabriel Dabscheck ◽  
Eunice K. Chan ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Drug Response ◽  
Absence Epilepsy ◽  
Rare Genetic Variants
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