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Kuchenbaecker, K.

Publications and source records attributed to Kuchenbaecker, K..

5 recordsLinked to original sources

Transcriptome-wide association study and fly experiments uncover the role of CoA synthase in ageing across species.

While significant progress has been made in understanding the genetic architecture of ageing in model organisms, our understanding of human ageing remains limited. We performed a multi-tissue Transcriptome-wide association study (TWAS) on human lifespan, integrating GWAS data from >1 million parental lifespans with gene expression prediction models derived from reference transcriptomic datasets; followed by replication using healthspan and longevity phenotypes as additional readouts of ageing. The TWAS uncovered 563 significant gene associations, of which 139 replicated. TOMM40, encoding a component of the mitochondrial outer membrane translocase that is fundamental for mitochondrial function, had the strongest association with parental lifespan and longevity and was fine-mapped as a putatively causal lifespan gene at the APOE-TOMM40 region. Uniquely in our study, we identified fly orthologues of replicating genes and examined if modulating their expression impacts Drosophila longevity. The nine novel associations with all three ageing outcomes included COASY, encoding Coenzyme A synthase. Knocking down its fly orthologue, Ppat-dpck, resulted in significant lifespan extension in flies. Hence, in addition to discovering new genes associated with human ageing, by combining human TWAS with experimental Drosophila work, we provide evidence for the role of COASY (Ppat-dpck) in ageing across species. Significance statementExtensive research on ageing has been conducted in Drosophila and C.elegans due to their short lifespan and experimental tractability. However, in human genetic research, only a few loci have been consistently replicated. To bridge this gap, we conducted a transcriptome-wide association study (TWAS) followed by experimental validation in Drosophila. TWAS revealed 139 significant and replicating gene associations, including COASY. Knockdown of its fly orthologue (Ppat-dpck) significantly extended fly lifespan, validating its roles in ageing across species. Thus, integrating multiple ageing outcomes through TWAS in human genetic research can uncover robust associations and highlight genes involved in fundamental ageing mechanisms.

genetics↗

The transferability of lipid-associated loci across African, Asian and European cohorts

The under-representation of non-European samples in genome-wide association studies could ultimately restrict who benefits from medical advances through genomic science. Our aim was therefore to address the fundamental question whether causal variants for blood lipids are shared across populations.\n\nA polygenic score based on established LDL-cholesterol-associated loci from European discovery samples had consistent effects on serum levels in samples from the UK, Uganda and Greek population isolates (correlation coefficient r=0.23 to 0.28 per LDL standard deviation, p<1.9x10-14). Trans-ethnic genetic correlations between European ancestry, Chinese and Japanese cohorts did not differ significantly from 1 for HDL, LDL and triglycerides. In each study, >60% of major lipid loci displayed evidence of replication with one exception. There was evidence for an effect on serum levels in the Ugandan samples for only 10% of major triglyceride loci. The PRS was only weakly associated in this group (r=0.06, SE=0.013). We establish trans-ethnic colocalization as a method to distinguish shared from population-specific trait loci.\n\nOur results provide evidence for high levels of consistency of genetic associations for cholesterol biomarkers across populations. However, we also demonstrate that the degree of shared causal genetic architecture can be population-, trait- and locus-specific. Efforts to implement genetic risk prediction in clinical settings should account for this.

genetics↗

Shared heritability and functional enrichment across six solid cancers

Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (rg=0.57, p=4.6x10-8), breast and ovarian cancer (rg=0.24, p=7x10-5), breast and lung cancer (rg=0.18, p=1.5x10-6) and breast and colorectal cancer (rg=0.15, p=1.1x10-4). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.

genomics↗

Cohort-wide deep whole genome sequencing and the allelic architecture of complex traits

The role of rare variants in complex traits remains uncharted. Here, we conduct deep whole genome sequencing of 1,457 individuals from an isolated population, and test for rare variant burdens across six cardiometabolic traits. We identify a role for rare regulatory variation, which has hitherto been missed. We find evidence of rare variant burdens overlapping with, and mostly independent of established common variant signals (ADIPOQ and adiponectin, P=4.2x10-8; APOC3 and triglyceride levels, P=1.58x10-26; GGT1 and gamma-glutamyltransferase, P=2.3x10-6; UGT1A9 and bilirubin, P=1.9x10-8), and identify replicating evidence for a burden associated with triglyceride levels in FAM189A (P=2.26x10-8), indicating a role for this gene in lipid metabolism.

genetics↗

Very low depth whole genome sequencing in complex trait association studies

MotivationVery low depth sequencing has been proposed as a cost-effective approach to capture low-frequency and rare variation in complex trait association studies. However, a full characterisation of the genotype quality and association power for very low depth sequencing designs is still lacking.\n\nResultsWe perform cohort-wide whole genome sequencing (WGS) at low depth in 1,239 individuals (990 at 1x depth and 249 at 4x depth) from an isolated population, and establish a robust pipeline for calling and imputing very low depth WGS genotypes from standard bioinformatics tools. Using genotyping chip, whole-exome sequencing (WES, 75x depth) and high-depth (22x) WGS data in the same samples, we examine in detail the sensitivity of this approach, and show that imputed 1x WGS recapitulates 95.2% of variants found by imputed GWAS with an average minor allele concordance of 97% for common and low-frequency variants. In our study, 1x further allowed the discovery of 140,844 true low-frequency variants with 73% genotype concordance when compared to high-depth WGS data. Finally, using association results for 57 quantitative traits, we show that very low depth WGS is an efficient alternative to imputed GWAS chip designs, allowing the discovery of up to twice as many true association signals than the classical imputed GWAS design.\n\nSupplementary DataSupplementary Data are appended to this manuscript.

genetics↗