scholarly journals Evaluation of gene-based family-based methods to detect novel genes associated with familial late onset Alzheimer disease

2018 ◽  
Author(s):  
Maria Victoria Fernández ◽  
John Budde ◽  
Jorge Del-Aguila ◽  
Laura Ibañez ◽  
Yuetiva Deming ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Rare Variants ◽  
Late Onset ◽  
Methodological Approach ◽  
Case Control Studies ◽  
High Confidence ◽  
Novel Genes ◽  
Practical Examination ◽  
Family Based ◽  
Study Designs

AbstractGene-based tests to study the combined effect of rare variants towards a particular phenotype have been widely developed for case-control studies, but their evolution and adaptation for family-based studies, especially for complex incomplete families, has been slower. In this study, we have performed a practical examination of all the latest gene-based methods available for family-based study designs using both simulated and real datasets. We have examined the performance of several collapsing, variance-component and transmission disequilibrium tests across eight different software and twenty-two models utilizing a cohort of 285 families (N=1,235) with late-onset Alzheimer disease (LOAD). After a thorough examination of each of these tests, we propose a methodological approach to identify, with high confidence, genes associated with the studied phenotype with high confidence and we provide recommendations to select the best software and model for family-based gene-based analyses. Additionally, in our dataset, we identified PTK2B, a GWAS candidate gene for sporadic AD, along with six novel genes (CHRD, CLCN2, HDLBP, CPAMD8, NLRP9, MAS1L) as candidates genes for familial LOAD.

scholarly journals Evaluation of Gene-Based Family-Based Methods to Detect Novel Genes Associated With Familial Late Onset Alzheimer Disease

2018 ◽  
Vol 12 ◽  
Author(s):  
Maria V. Fernández ◽  
John Budde ◽  
Jorge L. Del-Aguila ◽  
Laura Ibañez ◽  
Yuetiva Deming ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Late Onset ◽  
Novel Genes ◽  
Family Based

scholarly journals Identification of sixteen novel candidate genes for late onset Parkinson’s disease

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Alessandro Gialluisi ◽  
Mafalda Giovanna Reccia ◽  
Nicola Modugno ◽  
Teresa Nutile ◽  
Alessia Lombardi ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Candidate Genes ◽  
Rare Variants ◽  
Late Onset ◽  
High Specificity ◽  
Diagnostic Tools ◽  
Multi Stage ◽  
Whole Exome ◽  
Family Based

Abstract Background Parkinson’s disease (PD) is a neurodegenerative movement disorder affecting 1–5% of the general population for which neither effective cure nor early diagnostic tools are available that could tackle the pathology in the early phase. Here we report a multi-stage procedure to identify candidate genes likely involved in the etiopathogenesis of PD. Methods The study includes a discovery stage based on the analysis of whole exome data from 26 dominant late onset PD families, a validation analysis performed on 1542 independent PD patients and 706 controls from different cohorts and the assessment of polygenic variants load in the Italian cohort (394 unrelated patients and 203 controls). Results Family-based approach identified 28 disrupting variants in 26 candidate genes for PD including PARK2, PINK1, DJ-1(PARK7), LRRK2, HTRA2, FBXO7, EIF4G1, DNAJC6, DNAJC13, SNCAIP, AIMP2, CHMP1A, GIPC1, HMOX2, HSPA8, IMMT, KIF21B, KIF24, MAN2C1, RHOT2, SLC25A39, SPTBN1, TMEM175, TOMM22, TVP23A and ZSCAN21. Sixteen of them have not been associated to PD before, were expressed in mesencephalon and were involved in pathways potentially deregulated in PD. Mutation analysis in independent cohorts disclosed a significant excess of highly deleterious variants in cases (p = 0.0001), supporting their role in PD. Moreover, we demonstrated that the co-inheritance of multiple rare variants (≥ 2) in the 26 genes may predict PD occurrence in about 20% of patients, both familial and sporadic cases, with high specificity (> 93%; p = 4.4 × 10− 5). Moreover, our data highlight the fact that the genetic landmarks of late onset PD does not systematically differ between sporadic and familial forms, especially in the case of small nuclear families and underline the importance of rare variants in the genetics of sporadic PD. Furthermore, patients carrying multiple rare variants showed higher risk of manifesting dyskinesia induced by levodopa treatment. Conclusions Besides confirming the extreme genetic heterogeneity of PD, these data provide novel insights into the genetic of the disease and may be relevant for its prediction, diagnosis and treatment.

P2-105: NOMINATION OF NOVEL CANDIDATE GENES FOR FAMILIAL LATE ONSET ALZHEIMER DISEASE AFTER EVALUATION OF GENE-BASED FAMILY-BASED METHODS

2006 ◽  
Vol 14 (7S_Part_13) ◽  
pp. P709-P709
Author(s):  
Maria Victoria Fernandez ◽  
John P. Budde ◽  
Jorge L. Del-Aguila ◽  
Laura Ibanez ◽  
Yuetiva Deming ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Candidate Genes ◽  
Late Onset ◽  
Family Based

scholarly journals Rare ABCA7 variants in 2 German families with Alzheimer disease

2018 ◽  
Vol 4 (2) ◽  
pp. e224 ◽  
Author(s):  
Patrick May ◽  
Sabrina Pichler ◽  
Daniela Hartl ◽  
Dheeraj R. Bobbili ◽  
Manuel Mayhaus ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Rare Variants ◽  
Late Onset ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Whole Genome ◽  
Pathogenic Variants ◽  
Genome Wide

ObjectiveThe aim of this study was to identify variants associated with familial late-onset Alzheimer disease (AD) using whole-genome sequencing.MethodsSeveral families with an autosomal dominant inheritance pattern of AD were analyzed by whole-genome sequencing. Variants were prioritized for rare, likely pathogenic variants in genes already known to be associated with AD and confirmed by Sanger sequencing using standard protocols.ResultsWe identified 2 rare ABCA7 variants (rs143718918 and rs538591288) with varying penetrance in 2 independent German AD families, respectively. The single nucleotide variant (SNV) rs143718918 causes a missense mutation, and the deletion rs538591288 causes a frameshift mutation of ABCA7. Both variants have previously been reported in larger cohorts but with incomplete segregation information. ABCA7 is one of more than 20 AD risk loci that have so far been identified by genome-wide association studies, and both common and rare variants of ABCA7 have previously been described in different populations with higher frequencies in AD cases than in controls and varying penetrance. Furthermore, ABCA7 is known to be involved in several AD-relevant pathways.ConclusionsWe conclude that both SNVs might contribute to the development of AD in the examined family members. Together with previous findings, our data confirm ABCA7 as one of the most relevant AD risk genes.

scholarly journals SimRVSequences: an R package to simulate genetic sequence data for pedigrees

2019 ◽  
Author(s):  
Christina Nieuwoudt ◽  
Angela Brooks-Wilson ◽  
Jinko Graham
Keyword(s):  
Rare Variants ◽  
Sequence Data ◽  
Simulated Data ◽  
R Package ◽  
Single Nucleotide Variant ◽  
Ease Of Use ◽  
Case Control Studies ◽  
Single Nucleotide ◽  
Sequencing Errors ◽  
Family Based

1AbstractSummaryFamily-based studies have several advantages over case-control studies for finding causal rare variants for a disease; these include increased power, smaller sample size requirements, and improved detection of sequencing errors. However, collecting suitable families and compiling their data is time-consuming and expensive. To evaluate methodology to identify causal rare variants in family-based studies, one can use simulated data. For this purpose we present the R package SimRVSequences. Users supply a sample of pedigrees and single-nucleotide variant data from a sample of unrelated individuals representing the pedigree founders. Users may also model genetic heterogeneity among families. For ease of use, SimRVSequences offers methods to import and format single-nucleotide variant data and pedigrees from existing software.Availability and ImplementationSimRVSequences is available as a library for R≥ 3.5.0 on the comprehensive R archive network.

Association between ALDH2 Gene Polymorphism and Late-onset Alzheimer Disease: An Up-to-date Meta-analysis

2020 ◽  
Vol 17 (2) ◽  
pp. 105-111
Author(s):  
Haitao Liu ◽  
Wei Ge ◽  
Wei Chen ◽  
Xue Kong ◽  
Weiming Jian ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Large Scale ◽  
Late Onset ◽  
Meta Analysis ◽  
Case Control ◽  
Cochrane Library ◽  
Positive Trend ◽  
Case Control Studies ◽  
China National Knowledge Infrastructure ◽  
Aldh2 Gene

Objectives: Previous case-control studies have focused on the relationship between ALDH2 gene polymorphism and late-onset Alzheimer's Disease (LOAD), but no definite unified conclusion has been reached. Therefore, the correlation between ALDH2 Glu504Lys polymorphism and LOAD remains controversial. To analyze the correlation between ALDH2 polymorphism and the risk of LOAD, we implemented this up-to-date meta-analysis to assess the probable association. Methods: Studies were searched through China National Knowledge Infrastructure (CNKI), VIP Database for Chinese Technical Periodicals, China Biology Medicine, PubMed, Cochrane Library, Clinical- Trials.gov, Embase, and MEDLINE from January 1, 1994 to December 31, 2018, without any restrictions on language and ethnicity. Results: Five studies of 1057 LOAD patients and 1136 healthy controls met our criteria for the analysis. Statistically, the ALDH2 GA/AA genotype was not linked with raising LOAD risk (odds ratio (OR) = 1.48, 95% confidence interval (CI) = 0.96-2.28, p = 0.07). In subgroup analysis, the phenomenon that men with ALDH2*2 had higher risk for LOAD (OR = 1.72, 95%CI = 1.10-2.67, p = 0.02) was observed. Conclusions: This study comprehends only five existing case-control studies and the result is negative. The positive trend might appear when the sample size is enlarged. In the future, more large-scale casecontrol or cohort studies should be done to enhance the association between ALDH2 polymorphism and AD or other neurodegenerative diseases.

scholarly journals Case–Parent Trio Studies in Cleft Lip and Palate

2020 ◽  
Vol 07 (03) ◽  
pp. 075-079
Author(s):  
Mahamad Irfanulla Khan ◽  
Prashanth CS
Keyword(s):  
Genetic Variants ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Association Studies ◽  
Geographical Location ◽  
Genetic Association Studies ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Family Based ◽  
Study Designs

AbstractCleft lip with or without cleft palate (CL/P) is one of the most common congenital malformations in humans involving various genetic and environmental risk factors. The prevalence of CL/P varies according to geographical location, ethnicity, race, gender, and socioeconomic status, affecting approximately 1 in 800 live births worldwide. Genetic studies aim to understand the mechanisms contributory to a phenotype by measuring the association between genetic variants and also between genetic variants and phenotype population. Genome-wide association studies are standard tools used to discover genetic loci related to a trait of interest. Genetic association studies are generally divided into two main design types: population-based studies and family-based studies. The epidemiological population-based studies comprise unrelated individuals that directly compare the frequency of genetic variants between (usually independent) cases and controls. The alternative to population-based studies (case–control designs) includes various family-based study designs that comprise related individuals. An example of such a study is a case–parent trio design study, which is commonly employed in genetics to identify the variants underlying complex human disease where transmission of alleles from parents to offspring is studied. This article describes the fundamentals of case–parent trio study, trio design and its significances, statistical methods, and limitations of the trio studies.

scholarly journals Association between early bronchiolitis and the development of childhood asthma: a meta-analysis

BMJ Open ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. e043956
Author(s):  
Guizuo Wang ◽  
Dong Han ◽  
Zhengdong Jiang ◽  
Manxiang Li ◽  
Shumei Yang ◽  
...  
Keyword(s):  
Early Life ◽  
Fixed Effects ◽  
Late Onset ◽  
Meta Analysis ◽  
Later Life ◽  
Analysis Data ◽  
Fixed Effects Model ◽  
Case Control Studies ◽  
Increased Risk ◽  
Registration Number

ObjectiveEarly life bronchiolitis has been hypothesised to be associated with the subsequent risk of persistent wheezing or asthma. However, the link remains controversial. The objective of our study was to evaluate the association between bronchiolitis before 2 years of age and the late-onset wheezing/asthma.DesignSystematic review and meta-analysis.MethodsPubMed, Embase and Web of Science databases were systematically searched for studies published between 1955 and January 2020. Meanwhile, we also checked through the reference lists of relevant articles to see whether these references included reports of other studies that might be eligible for the review. Cohort and case–control studies assessing the association between early-life bronchiolitis and late-onset wheezing/asthma were included in this meta-analysis. Data were extracted by two independent reviewers. Results were pooled using a random-effects model or fixed-effects model according to the heterogeneity among studies.Results32 original articles with 292 844 participants, which met the criteria, were included in this meta-analysis. Bronchiolitis before 2 years of age was associated with an increased risk of subsequent wheezing/asthma (relative risk=2.46, 95% CI 2.14 to 2.82, p<0.001). After categorising studies into different groups based on age at the end of follow-up, geographical region and study quality, the association still remained significant.ConclusionsThe meta-analysis indicates an association between bronchiolitis before 2 years of age and the wheezing/asthma in later life. Well-designed and highly standardised prospective studies that better address bias due to potential confounding factors are needed to validate the risk identified in our meta-analysis.PROSPERO registration numberCRD42018089453.

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