Background Patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease 2019 (COVID-19), exhibit a wide spectrum of disease behaviour. Since DNA methylation has been implicated in the regulation of viral infections and the immune system, we performed an epigenome-wide association study (EWAS) to identify candidate loci regulated by this epigenetic mark that could be involved in the onset of COVID-19 in patients without comorbidities. Methods Peripheral blood samples were obtained from 407 confirmed COVID-19 patients ≤ 61 years of age and without comorbidities, 194 (47.7%) of whom had mild symptomatology that did not involve hospitalization and 213 (52.3%) had a severe clinical course that required respiratory support. The set of cases was divided into discovery ( n = 207) and validation ( n = 200) cohorts, balanced for age and sex of individuals. We analysed the DNA methylation status of 850,000 CpG sites in these patients. Findings The DNA methylation status of 44 CpG sites was associated with the clinical severity of COVID-19. Of these loci, 23 (52.3%) were located in 20 annotated coding genes. These genes, such as the inflammasome component Absent in Melanoma 2 (AIM2) and the Major Histocompatibility Complex, class I C (HLA-C) candidates, were mainly involved in the response of interferon to viral infection. We used the EWAS-identified sites to establish a DNA methylation signature (EPICOVID) that is associated with the severity of the disease. Interpretation We identified DNA methylation sites as epigenetic susceptibility loci for respiratory failure in COVID-19 patients. These candidate biomarkers, combined with other clinical, cellular and genetic factors, could be useful in the clinical stratification and management of patients infected with the SARS-CoV-2. Funding The Unstoppable campaign of the Josep Carreras Leukaemia Foundation, the Cellex Foundation and the CERCA Programme/Generalitat de Catalunya.

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.

Data availabilitySummary statistics generated by COVID-19 Host Genetics Initiative are available online (https://www.covid19hg.org/results/r6/). The analyses described here use the freeze 6 data. The COVID-19 Host Genetics Initiative continues to regularly release new data freezes. Summary statistics for samples from individuals of non-European ancestry are not currently available owing to the small individual sample sizes of these groups, but the results for 23 loci lead variants are reported in Supplementary Table 3. Individual-level data can be requested directly from the authors of the contributing studies, listed in Supplementary Table 1.

Hemorrhagic transformation is a complication of recombinant tissue-plasminogen activator (rtPA) treatment. The most severe form, parenchymal hematoma, can result in neurological deterioration, disability, and death. Our objective is to identify single nucleotide variations associated with a risk of parenchymal hematoma following thrombolytic therapy in acute ischemic stroke patients. A fixed-effect genome-wide metanalysis was performed combining two-stage Genome Wide Association studies (GWAs) (n = 1,904). The Discovery Stage (3 cohorts) comprised 1,324 ischemic stroke individuals, of whom 5.4% had a parenchymal hematoma. Genetic variants yielding a p-value &lt;1x10−5 were analyzed in the Validation Stage (6 cohorts), formed by 580 ischemic stroke patients with 12.1% hemorrhagic events. All the participants received rtPA; cases were parenchymal hematoma type 1 or 2 as defined by the ECASS criteria. Genome-wide significant findings (p &lt; 5x10−8) were characterized by in-silico functional annotation, gene expression, and DNA regulatory elements. We analyzed 7,989,272 single nucleotide polymorphisms (SNPs) and identified a Genome-wide association locus on chromosome 20 in the Discovery Cohort; functional annotation indicated that the ZBTB46 gene was driving the association for Chrosome 20. The top SNP was rs76484331 in the ZBTB46 gene (p = 2.49x10−8; odds ratio (OR): 11.21; 95% confidence interval (CI): 4.82–26.55). In the Replication Cohort (n = 580), the rs76484331 polymorphism was associated with parenchymal hematoma (p = 0.01), and the overall association after meta-analysis increased (p = 1.61x10−8; OR: 5.84; 95%CI: 3.16–10.76). ZBTB46 codes the Zinc Finger and BTB domain-containing protein 46 that acts as a transcription factor. In-silico studies indicated that ZBTB46 is expressed in brain tissue by neurons and endothelial cells. Moreover, rs76484331 interacts with the promoter sites located at 20q13. In conculsion, we identified single nucleotide variants in the ZBTB46 gene associated with a higher risk of parenchymal hematoma following rtPA treatment.

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