scholarly journals Assessing Whether an Allele Can Account in Part for a Linkage Signal: The Genotype-IBD Sharing Test (GIST)

2004 ◽  
Vol 74 (3) ◽  
pp. 418-431 ◽  
Author(s):  
Chun Li ◽  
Laura J. Scott ◽  
Michael Boehnke
Keyword(s):  
BMC Genetics ◽  
2005 ◽  
Vol 6 (Suppl 1) ◽  
pp. S88 ◽  
Author(s):  
Ming-Huei Chen ◽  
Paul Van Eerdewegh ◽  
Josée Dupuis

2007 ◽  
Vol 31 (7) ◽  
pp. 727-740 ◽  
Author(s):  
Joanna M. Biernacka ◽  
Heather J. Cordell
Keyword(s):  

Blood ◽  
2000 ◽  
Vol 95 (9) ◽  
pp. 2780-2785 ◽  
Author(s):  
José Manuel Soria ◽  
Laura Almasy ◽  
Juan Carlos Souto ◽  
Isabel Tirado ◽  
Montserrat Borell ◽  
...  

Association studies suggest that the G20210A mutation (G to A substitution at nucleotide position 20210) in the prothrombin gene (PT) is associated with increased plasma prothrombin activity and with increased risk for venous thromboembolism. To test directly for linkage between this PT variant and plasma prothrombin activity we performed a family-based study. The G20210A genotypes and plasma prothrombin activity levels were determined in 435 individuals belonging to 22 extended Spanish families. The sample was composed of 388 homozygous (G/G) normal individuals and 43 heterozygote (G/A) and 4 homozygote (A/A) carriers for the G20210A mutation. The results of variance-component linkage analysis yielded a highly significant lod score of 3.6 (P = 2.4 × 10−5) between this mutation and a quantitative trait locus (QTL) that influences prothrombin activity. Importantly, a conditional linkage analysis that simultaneously accounted for association with the G20210A variant completely eliminated the linkage signal, which indicates that this mutation affects the function of the prothrombin gene. Additionally, a bivariate linkage analysis of plasma prothrombin activity and thrombosis significantly improved the linkage signal for prothrombin activity (lod score = 4.7;P = 1.5 × 10−6) and provided strong evidence that this QTL has a pleiotropic effect on the risk of thrombosis (lod score = 2.43; P = .0004). These results represent the first direct genetic evidence that a QTL in thePT gene influences prothrombin activity levels and susceptibility to thrombosis and strongly support the conclusion that G20210A is a functional polymorphism.


2006 ◽  
Vol 38 (8) ◽  
pp. 858-859 ◽  
Author(s):  
Enrico Petretto ◽  
Jonathan Mangion ◽  
Stuart A Cook ◽  
Timothy J Aitman ◽  
Michal Pravenec ◽  
...  

2006 ◽  
Vol 38 (8) ◽  
pp. 856-858 ◽  
Author(s):  
Elissa J Chesler ◽  
Leonid Bystrykh ◽  
Gerald de Haan ◽  
Michael P Cooke ◽  
Andrew Su ◽  
...  

2003 ◽  
Vol 53 (3) ◽  
pp. 239-243 ◽  
Author(s):  
Thomas G Schulze ◽  
Y.u-Sheng Chen ◽  
Judith A Badner ◽  
Melvin G McInnis ◽  
J.Raymond DePaulo ◽  
...  

2021 ◽  
Vol 46 (2) ◽  
Author(s):  
Claudio Toma ◽  
Alex D. Shaw ◽  
Anna Heath ◽  
Kerrie D. Pierce ◽  
Philip B. Mitchell ◽  
...  

Background: Bipolar disorder is a highly heritable psychiatric condition for which specific genetic factors remain largely unknown. In the present study, we used combined whole-exome sequencing and linkage analysis to identify risk loci and dissect the contribution of common and rare variants in families with a high density of illness. Methods: Overall, 117 participants from 15 Australian extended families with bipolar disorder (72 with affective disorder, including 50 with bipolar disorder type I or II, 13 with schizoaffective disorder–manic type and 9 with recurrent unipolar disorder) underwent whole-exome sequencing. We performed genome-wide linkage analysis using MERLIN and conditional linkage analysis using LAMP. We assessed the contribution of potentially functional rare variants using a genebased segregation test. Results: We identified a significant linkage peak on chromosome 10q11-q21 (maximal single nucleotide polymorphism = rs10761725; exponential logarithm of the odds [LODexp] = 3.03; empirical p = 0.046). The linkage interval spanned 36 protein-coding genes, including a gene associated with bipolar disorder, ankyrin 3 (ANK3). Conditional linkage analysis showed that common ANK3 risk variants previously identified in genome-wide association studies — or variants in linkage disequilibrium with those variants — did not explain the linkage signal (rs10994397 LOD = 0.63; rs9804190 LOD = 0.04). A family-based segregation test with 34 rare variants from 14 genes under the linkage interval suggested rare variant contributions of 3 brain-expressed genes: NRBF2 (p = 0.005), PCDH15 (p = 0.002) and ANK3 (p = 0.014). Limitations: We did not examine non-coding variants, but they may explain the remaining linkage signal. Conclusion: Combining family-based linkage analysis with next-generation sequencing data is effective for identifying putative disease genes and specific risk variants in complex disorders. We identified rare missense variants in ANK3, PCDH15 and NRBF2 that could confer disease risk, providing valuable targets for functional characterization.


2008 ◽  
Vol 17 (6) ◽  
pp. 699-700 ◽  
Author(s):  
Daniel B Campbell

2005 ◽  
Vol 76 (6) ◽  
pp. 934-949 ◽  
Author(s):  
Mingyao Li ◽  
Michael Boehnke ◽  
Gonçalo R. Abecasis

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