1. |
- Turcot, Valerie, et al.
(author)
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Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity
- 2018
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In: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 50:1, s. 26-41
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are similar to 10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed similar to 7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity.
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2. |
- Evangelou, Evangelos, et al.
(author)
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Genetic analysis of over 1 million people identifies 535 new loci associated with blood pressure traits.
- 2018
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:10, s. 1412-1425
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Journal article (peer-reviewed)abstract
- High blood pressure is a highly heritable and modifiable risk factor for cardiovascular disease. We report the largest genetic association study of blood pressure traits (systolic, diastolic and pulse pressure) to date in over 1 million people of European ancestry. We identify 535 novel blood pressure loci that not only offer new biological insights into blood pressure regulation but also highlight shared genetic architecture between blood pressure and lifestyle exposures. Our findings identify new biological pathways for blood pressure regulation with potential for improved cardiovascular disease prevention in the future.
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3. |
- Mahajan, Anubha, et al.
(author)
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Refining the accuracy of validated target identification through coding variant fine-mapping in type 2 diabetes
- 2018
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In: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 50:4, s. 559-571
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Journal article (peer-reviewed)abstract
- We aggregated coding variant data for 81,412 type 2 diabetes cases and 370,832 controls of diverse ancestry, identifying 40 coding variant association signals (P < 2.2 × 10−7); of these, 16 map outside known risk-associated loci. We make two important observations. First, only five of these signals are driven by low-frequency variants: even for these, effect sizes are modest (odds ratio ≤1.29). Second, when we used large-scale genome-wide association data to fine-map the associated variants in their regional context, accounting for the global enrichment of complex trait associations in coding sequence, compelling evidence for coding variant causality was obtained for only 16 signals. At 13 others, the associated coding variants clearly represent ‘false leads’ with potential to generate erroneous mechanistic inference. Coding variant associations offer a direct route to biological insight for complex diseases and identification of validated therapeutic targets; however, appropriate mechanistic inference requires careful specification of their causal contribution to disease predisposition.
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4. |
- Corbin, Laura J., et al.
(author)
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Formalising recall by genotype as an efficient approach to detailed phenotyping and causal inference
- 2018
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Journal article (peer-reviewed)abstract
- Detailed phenotyping is required to deepen our understanding of the biological mechanisms behind genetic associations. In addition, the impact of potentially modifiable risk factors on disease requires analytical frameworks that allow causal inference. Here, we discuss the characteristics of Recall-by-Genotype (RbG) as a study design aimed at addressing both these needs. We describe two broad scenarios for the application of RbG: studies using single variants and those using multiple variants. We consider the efficacy and practicality of the RbG approach, provide a catalogue of UK-based resources for such studies and present an online RbG study planner.
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5. |
- Larsson, Susanna C, et al.
(author)
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Serum 25-Hydroxyvitamin D Concentrations and Ischemic Stroke and Its Subtypes.
- 2018
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In: Stroke. - 0039-2499 .- 1524-4628. ; 49:10, s. 2508-2511
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Journal article (peer-reviewed)abstract
- Background and Purpose- Observational studies have reported increased risk of ischemic stroke among individuals with low serum 25-hydroxyvitamin D (S-25OHD) concentrations but uncertainty remains about the causality of this association. We sought to determine whether S-25OHD concentrations are causally associated with ischemic stroke and its subtypes using Mendelian randomization. Methods- We used summary-level data for ischemic stroke (34 217 cases and 404 630 noncases) from the MEGASTROKE consortium. As instruments, we used 6 single nucleotide polymorphisms, explaining 7.5% of the variance in S-25OHD, previously identified to be associated with S-25OHD concentrations in the Study of Underlying Genetic Determinants of Vitamin D and Highly Related Traits consortium (n=79 366). The analyses were conducted using the inverse-variance-weighted method and complemented with the weighted median, heterogeneity-penalized, and Mendelian randomization-Egger approaches. Results- Genetically higher S-25OHD concentration was not associated with ischemic stroke. The odds ratios (95% CI) per genetically predicted 1-SD (≈18 nmol/L) increase in S-25OHD concentrations, based on all 6 single nucleotide polymorphisms, were 1.01 (0.94-1.08; P=0.84) for all ischemic stroke, 0.94 (0.80-1.11; P=0.49) for large artery stroke, 0.95 (0.82-1.11; P=0.55) for small vessel stroke, and 1.02 (0.90-1.16; P=0.74) for cardioembolic stroke. The results were similar in sensitivity analyses. Conclusions- These findings provide no support that higher S-25OHD concentrations are causally associated with any ischemic stroke subtype. Thus, vitamin D supplementation will unlikely reduce the risk of ischemic stroke in the general population.
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