Sigrún H. Lund

Abstract High-throughput proteomics platforms measuring thousands of proteins in plasma combined with genomic and phenotypic information have the power to bridge the gap between the genome and diseases. Here we performed association studies of Olink Explore 3072 data generated by the UK Biobank Pharma Proteomics Project 1 on plasma samples from more than 50,000 UK Biobank participants with phenotypic and genotypic data, stratifying on British or Irish, African and South Asian ancestries. We compared the results with those of a SomaScan v4 study on plasma from 36,000 Icelandic people 2 , for 1,514 of whom Olink data were also available. We found modest correlation between the two platforms. Although cis protein quantitative trait loci were detected for a similar absolute number of assays on the two platforms (2,101 on Olink versus 2,120 on SomaScan), the proportion of assays with such supporting evidence for assay performance was higher on the Olink platform (72% versus 43%). A considerable number of proteins had genomic associations that differed between the platforms. We provide examples where differences between platforms may influence conclusions drawn from the integration of protein levels with the study of diseases. We demonstrate how leveraging the diverse ancestries of participants in the UK Biobank helps to detect novel associations and refine genomic location. Our results show the value of the information provided by the two most commonly used high-throughput proteomics platforms and demonstrate the differences between them that at times provides useful complementarity.

Osteoarthritis affects over 300 million people worldwide. Here, we conduct a genome-wide association study meta-analysis across 826,690 individuals (177,517 with osteoarthritis) and identify 100 independently associated risk variants across 11 osteoarthritis phenotypes, 52 of which have not been associated with the disease before. We report thumb and spine osteoarthritis risk variants and identify differences in genetic effects between weight-bearing and non-weight-bearing joints. We identify sex-specific and early age-at-onset osteoarthritis risk loci. We integrate functional genomics data from primary patient tissues (including articular cartilage, subchondral bone, and osteophytic cartilage) and identify high-confidence effector genes. We provide evidence for genetic correlation with phenotypes related to pain, the main disease symptom, and identify likely causal genes linked to neuronal processes. Our results provide insights into key molecular players in disease processes and highlight attractive drug targets to accelerate translation.

OBJECTIVES: Acute thoracic aortic dissection (ATAD) is a devastating condition associated with a high mortality rate. Recent reports suggest that its incidence is rising. Utilizing nationwide data comprising the whole Icelandic population, we aimed to determine the incidence, mortality rate and time-dependent mortality risk of ATAD. METHODS: Data were retrospectively collected using centralized hospital discharge registries, autopsy records and Cause of Death Registry in Iceland from 1992 to 2013. RESULTS: Age- and gender-adjusted incidence of ATAD was 2.53/100 000/year, and no significant change in incidence was observed during the study period. The mean age was 66.9 ± 13.6 years and 66.0% (101/153) were Stanford type A. Of the whole group, 17.6% (27/153) died prior to hospital arrival, whereas the risk of death for patients who arrived alive to a hospital was 21.4% (27/126) within 24 h and 45.2% (57/126) at 30 days. During the course of the study, patients with type A dissection were more likely to undergo an operation and the management of type B dissection changed from open to endovascular repair. The 30-day mortality rate declined every year and the 5-year survival rate improved in the last third of the study. CONCLUSIONS: The incidence of ATAD was 2.53/100 000/year and remained constant throughout the study, contradicting recent perceptions of a rising incidence. ATAD, type A in particular, remains a highly lethal condition: Over half of all patients die within 30 days of the index event. A reduced 30-day mortality rate and an increased long-term survival rate indicate improved overall outcomes in patients with this complex condition.

Nonalcoholic fatty liver (NAFL) and its sequelae are growing health problems. We performed a genome-wide association study of NAFL, cirrhosis and hepatocellular carcinoma, and integrated the findings with expression and proteomic data. For NAFL, we utilized 9,491 clinical cases and proton density fat fraction extracted from 36,116 liver magnetic resonance images. We identified 18 sequence variants associated with NAFL and 4 with cirrhosis, and found rare, protective, predicted loss-of-function variants in MTARC1 and GPAM, underscoring them as potential drug targets. We leveraged messenger RNA expression, splicing and predicted coding effects to identify 16 putative causal genes, of which many are implicated in lipid metabolism. We analyzed levels of 4,907 plasma proteins in 35,559 Icelanders and 1,459 proteins in 47,151 UK Biobank participants, identifying multiple proteins involved in disease pathogenesis. We show that proteomics can discriminate between NAFL and cirrhosis. The present study provides insights into the development of noninvasive evaluation of NAFL and new therapeutic options.