About: Genetic linkage is a research topic. Over the lifetime, 8627 publications have been published within this topic receiving 471694 citations.
Papers published on a yearly basis
TL;DR: A locus segregating with familial Alzheimer's disease (AD) has been mapped to chromosome 21, close to the amyloid precursor protein (APP) gene as discussed by the authors, which suggests that some cases of AD could be caused by mutations in the APP gene.
Abstract: A locus segregating with familial Alzheimer's disease (AD) has been mapped to chromosome 21, close to the amyloid precursor protein (APP) gene. Recombinants between the APP gene and the AD locus have been reported which seemed to exclude it as the site of the mutation causing familial AD. But recent genetic analysis of a large number of AD families has demonstrated that the disease is heterogeneous. Families with late-onset AD do not show linkage to chromosome 21 markers. Some families with early-onset AD show linkage to chromosome 21 markers, but some do not. This has led to the suggestion that there is non-allelic genetic heterogeneity even within early onset familial AD. To avoid the problems that heterogeneity poses for genetic analysis, we have examined the cosegregation of AD and markers along the long arm of chromosome 21 in a single family with AD confirmed by autopsy. Here we demonstrate that in this kindred, which shows linkage to chromosome 21 markers, there is a point mutation in the APP gene. This mutation causes an amino-acid substitution (Val----Ile) close to the carboxy terminus of the beta-amyloid peptide. Screening other cases of familial AD revealed a second unrelated family in which this variant occurs. This suggests that some cases of AD could be caused by mutations in the APP gene.
TL;DR: A minimal cosegregating region containing the AD3 gene is defined, and at least 19 different transcripts encoded within this region corresponds to a novel gene whose product is predicted to contain multiple transmembrane domains and resembles an integral membrane protein.
Abstract: Some cases of Alzheimer's disease are inherited as an autosomal dominant trait. Genetic linkage studies have mapped a locus (AD3) associated with susceptibility to a very aggressive form of Alzheimer's disease to chromosome 14q24.3. We have defined a minimal cosegregating region containing the AD3 gene, and isolated at least 19 different transcripts encoded within this region. One of these transcripts (S182) corresponds to a novel gene whose product is predicted to contain multiple transmembrane domains and resembles an integral membrane protein. Five different missense mutations have been found that cosegregate with early-onset familial Alzheimer's disease. Because these changes occurred in conserved domains of this gene, and are not present in normal controls, they are likely to be causative of AD3.
TL;DR: The statistical basis for this "transmission test for linkage disequilibrium" (transmission/disequilibrium test] is described and the relationship of this test to tests of cosegregation that are based on the proportion of haplotypes or genes identical by descent in affected sibs is shown.
Abstract: A population association has consistently been observed between insulin-dependent diabetes mellitus (IDDM) and the "class 1" alleles of the region of tandem-repeat DNA (5' flanking polymorphism [5'FP]) adjacent to the insulin gene on chromosome 11p. This finding suggests that the insulin gene region contains a gene or genes contributing to IDDM susceptibility. However, several studies that have sought to show linkage with IDDM by testing for cosegregation in affected sib pairs have failed to find evidence for linkage. As means for identifying genes for complex diseases, both the association and the affected-sib-pairs approaches have limitations. It is well known that population association between a disease and a genetic marker can arise as an artifact of population structure, even in the absence of linkage. On the other hand, linkage studies with modest numbers of affected sib pairs may fail to detect linkage, especially if there is linkage heterogeneity. We consider an alternative method to test for linkage with a genetic marker when population association has been found. Using data from families with at least one affected child, we evaluate the transmission of the associated marker allele from a heterozygous parent to an affected offspring. This approach has been used by several investigators, but the statistical properties of the method as a test for linkage have not been investigated. In the present paper we describe the statistical basis for this "transmission test for linkage disequilibrium" (transmission/disequilibrium test [TDT]). We then show the relationship of this test to tests of cosegregation that are based on the proportion of haplotypes or genes identical by descent in affected sibs. The TDT provides strong evidence for linkage between the 5'FP and susceptibility to IDDM. The conclusions from this analysis apply in general to the study of disease associations, where genetic markers are usually closely linked to candidate genes. When a disease is found to be associated with such a marker, the TDT may detect linkage even when haplotype-sharing tests do not.
University of Kiel1, Cedars-Sinai Medical Center2, Wellcome Trust Sanger Institute3, University of Pennsylvania4, QIMR Berghofer Medical Research Institute5, Peninsula College of Medicine and Dentistry6, University of Edinburgh7, University of Cambridge8, University of Otago9, University of Washington10, University of Groningen11, University of Liège12, Harvard University13, Casa Sollievo della Sofferenza14, King's College London15, University of Chicago16, Yale University17, Johns Hopkins University18, Ludwig Maximilian University of Munich19, Charité20, McGill University21, Lille University of Science and Technology22, Cincinnati Children's Hospital Medical Center23, Ghent University24, Torbay Hospital25, Mater Health Services26, Université libre de Bruxelles27, RWTH Aachen University28, University of Utah29, Örebro University30, Leiden University31, University of Paris32, Technion – Israel Institute of Technology33, University of Western Australia34, Tel Aviv University35, University of Dundee36, University of Manchester37, University of Pittsburgh38, Royal Hospital for Sick Children39, Katholieke Universiteit Leuven40, Guy's and St Thomas' NHS Foundation Trust41, University of Bern42, University of Toronto43, University of Amsterdam44, Karolinska Institutet45, University of Zurich46, Université de Montréal47, Emory University48, Newcastle University49
TL;DR: A meta-analysis of six Crohn's disease genome-wide association studies and a series of in silico analyses highlighted particular genes within these loci implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP.
Abstract: We undertook a meta-analysis of six Crohn's disease genome-wide association studies (GWAS) comprising 6,333 affected individuals (cases) and 15,056 controls and followed up the top association signals in 15,694 cases, 14,026 controls and 414 parent-offspring trios. We identified 30 new susceptibility loci meeting genome-wide significance (P < 5 × 10⁻⁸). A series of in silico analyses highlighted particular genes within these loci and, together with manual curation, implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP. Combined with previously confirmed loci, these results identify 71 distinct loci with genome-wide significant evidence for association with Crohn's disease.
TL;DR: The chromosomal localization of the Huntington's disease gene is the first step in using recombinant DNA technology to identify the primary genetic defect in this disorder.
Abstract: Family studies show that the Huntington's disease gene is linked to a polymorphic DNA marker that maps to human chromosome 4. The chromosomal localization of the Huntington's disease gene is the first step in using recombinant DNA technology to identify the primary genetic defect in this disorder.
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