| 1. |
- Mayes, Maureen D, et al.
(författare)
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Immunochip analysis identifies multiple susceptibility Loci for systemic sclerosis.
- 2014
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 94:1, s. 47-61
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Tidskriftsartikel (refereegranskat)abstract
- In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci.
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| 2. |
- Hagenblad, Jenny, 1974-, et al.
(författare)
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Haplotype Structure and Phenotypic Associations in the Chromosomal Regions Surrounding Two Arabidopsis thaliana Flowering Time Loci
- 2004
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Ingår i: Genetics. - : Genetics Society of America. - 0016-6731 .- 1943-2631. ; 168:3, s. 1627-1638
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Tidskriftsartikel (refereegranskat)abstract
- The feasibility of using linkage disequilbrium (LD) to fine-map loci underlying natural variation in Arabidopsis thaliana was investigated by looking for associations between flowering time and marker polymorphism in the genomic regions containing two candidate genes, FRI and FLC, both of which are known to contribute to natural variation in flowering. A sample of 196 accessions was used, and polymorphism was assessed by sequencing a total of 17 roughly 500-bp fragments. Using a novel Bayesian algorithm based on haplotype similarity, we demonstrate that LD could have been used to fine-map the FRI gene to a roughly 30-kb region and to identify two common loss-of-function alleles. Interestingly, because of genetic heterogeneity, simple single-marker associations would not have been able to map FRI with nearly the same precision. No clear evidence for previously unknown alleles at either locus was found, but the effect of population structure in causing false positives was evident.
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| 3. |
- Sovio, Ulla, et al.
(författare)
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Association between Common Variation at the FTO Locus and Changes in Body Mass Index from Infancy to Late Childhood : The Complex Nature of Genetic Association through Growth and Development
- 2011
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 7:2, s. e1001307-
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Tidskriftsartikel (refereegranskat)abstract
- An age-dependent association between variation at the FTO locus and BMI in children has been suggested. We meta-analyzed associations between the FTO locus (rs9939609) and BMI in samples, aged from early infancy to 13 years, from 8 cohorts of European ancestry. We found a positive association between additional minor (A) alleles and BMI from 5.5 years onwards, but an inverse association below age 2.5 years. Modelling median BMI curves for each genotype using the LMS method, we found that carriers of minor alleles showed lower BMI in infancy, earlier adiposity rebound (AR), and higher BMI later in childhood. Differences by allele were consistent with two independent processes: earlier AR equivalent to accelerating developmental age by 2.37% (95% CI 1.87, 2.87, p = 10−20) per A allele and a positive age by genotype interaction such that BMI increased faster with age (p = 10−23). We also fitted a linear mixed effects model to relate genotype to the BMI curve inflection points adiposity peak (AP) in infancy and AR. Carriage of two minor alleles at rs9939609 was associated with lower BMI at AP (−0.40% (95% CI: −0.74, −0.06), p = 0.02), higher BMI at AR (0.93% (95% CI: 0.22, 1.64), p = 0.01), and earlier AR (−4.72% (−5.81, −3.63), p = 10−17), supporting cross-sectional results. Overall, we confirm the expected association between variation at rs9939609 and BMI in childhood, but only after an inverse association between the same variant and BMI in infancy. Patterns are consistent with a shift on the developmental scale, which is reflected in association with the timing of AR rather than just a global increase in BMI. Results provide important information about longitudinal gene effects and about the role of FTO in adiposity. The associated shifts in developmental timing have clinical importance with respect to known relationships between AR and both later-life BMI and metabolic disease risk.
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