key: cord-0798204-b22yp79t
authors: Wooster, L.; Nicholson, C. J.; Sigurslid, H. H.; Lino Cardenas, C. L.; Malhotra, R.
title: Polymorphisms in the ACE2 Locus Associate with Severity of COVID-19 Infection
date: 2020-06-22
journal: nan
DOI: 10.1101/2020.06.18.20135152
sha: bf79e1f9106631f2793aa91121fcab7783cb284d
doc_id: 798204
cord_uid: b22yp79t

The mechanisms underlying risk of developing severe outcomes due to COVID-19 have not yet been fully elucidated. The SARS-CoV-2 virus has a marked affinity to the human angiotensin-converting enzyme 2 (ACE2) receptor. The ACE2 locus is highly polymorphic, and this genetic variability may affect COVID-19 disease severity. Here, we analyzed associations between polymorphisms in the ACE2 locus and COVID-19 severity in 62 patients found to be COVID-19 positive by polymerase chain reaction. Of these patients, 23 required hospitalization due to COVID-19 infection. Of 61 ACE2 single nucleotide polymorphisms (SNPs) genotyped in this patient cohort, 10 were significantly associated with tissue expression of ACE2. Logistic regression adjusted for age and sex identified six of these ten SNPs to be significantly associated with hospitalization. These results provide preliminary evidence of a link between the ACE2 genotype and COVID-19 disease severity and suggest that the ACE2 genotype may inform COVID-19 risk stratification and need for more intense therapy.

The mechanisms linked to severity of coronavirus disease 2019 (COVID-19), which has thus far taken the lives of more than 400,000 people worldwide, are not yet understood. Data from clinical studies suggests a strong association between underlying cardiometabolic disease and worse outcomes in COVID-19. 1 One potential explanation behind this phenomenon may involve the higher expression of angiotensin-converting enzyme 2 (ACE2) receptor in these patients. 2 COVID-19 infection is caused by binding of the SARS-CoV-2 virus through its spike (S) proteins to the ACE2 receptor, principally in Type II alveolar cells of the lung. 3 ACE2 is also highly expressed in cardiac tissue and vascular endothelial cells, which may therefore provide a mechanism by which SARS-CoV-2 promotes direct injury of these tissues. 4, 5 Since interactions between the virus and ACE2 receptor are critical for virus entry into host cells, genetic polymorphisms that regulate ACE2 expression and/or the strength of these interactions may affect COVID-19 severity. 6 Recent studies aimed to compare the prevalence of ACE2 functional coding variants in different populations with endemic COVID-19. [6] [7] [8] However, to date there are no data showing a relationship between ACE2 genetic variants and clinical outcomes with COVID-19. The present study aims to analyze novel associations between mRNA expressionaltering genetic variants of human ACE2 and clinical severity in patients with COVID-19.

Consecutive patients diagnosed with COVID-19 throughout the Partners Hospital System who were previously genotyped as part of the Partners Biobank repository were studied. All genotyping was performed using the Illumina Infinium MEGA Consortium v1 SNP array. The Genotype-Tissue Expression (GTEx) project dataset (v8 release) was used to determine SNPs . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted June 22, 2020. . https://doi.org/10.1101/2020.06.18.20135152 doi: medRxiv preprint with a significant association with ACE2 tissue mRNA expression (expression quantitative trait loci, eQTLs) with a minor allele frequency (MAF) of at least 5%. 9 No coding variants were included in analysis as none met the threshold of 5% MAF in this cohort. ACE2 is located on the X chromosome but has been shown to escape X inactivation. 10 Therefore, logistic regression analysis adjusted for age and sex (Plink v1.07) was performed using allelic count where males were 0 or 1 and females 0, 1, or 2. We analyzed the effects of ACE2 minor allele dosage on requirement for hospitalization due to COVID-19. This study was approved by the Partners institutional review board (IRB protocol #2020P000982).

Among 30,752 previously genotyped Caucasian patients in the Partners Biobank, 62 were found to be COVID-19 positive by polymerase chain reaction between 1 st March and 16 th May 2020. Hospitalization status was determined on 27 th May by review of the electronic medical records. The median (IQR) age of this cohort was 62 (52, 73) years and 44% were female ( Table   1) . Of these patients, 23 (37%) required hospitalization due to COVID-19 infection. Across this cohort, we performed a case/control genetic association analysis on ACE2 polymorphisms. 9 Of 61 ACE2 single nucleotide polymorphisms (SNPs) genotyped in this patient cohort, 10 were significant eQTLs for ACE2 in at least one tissue type (P<1E-4) with some exhibiting linkage disequilibrium ( Table 2) . Of the 10 SNPs, five polymorphisms (rs4240157, rs6632680, rs4830965, rs1476524, and rs2048683), with minor alleles that associated with higher tissue expression of ACE2, 9 were associated with increased need for hospitalization due to COVID-19 even after adjusting for age and sex (odds ratio 2.9-4.3, P<0.05 for all). Similarly, an ACE2 polymorphism (rs1548474) whose minor allele associated with lower tissue expression was . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 22, 2020. . https://doi.org/10.1101/2020.06.18.20135152 doi: medRxiv preprint associated with lesser COVID-19 severity not requiring hospitalization (odds ratio 0.27, 95% CI 0.08-0.85, P=0.025, Table 3 ).

Previous studies have investigated the potential for ACE2 polymorphisms to explain population-based differences in COVID-19 severity. Cao et al. found no direct evidence of population differences in coronavirus S-protein binding-resistant mutants. However, considerably higher allele frequencies for SNPs associated with higher ACE2 expression in tissues were observed in the East Asian populations. 6 Asselta et al. reported no significant differences in the burden of rare deleterious ACE2 variants when comparing an Italian population with Europeans and East Asians. 7 In contrast, using single cell sequencing, Zhao et al.

demonstrated that ACE2 was more abundantly expressed in type II alveolar cells from an Asian male donor, when compared to white and African American donors. 8 Whilst these studies shed light on the contribution of ACE2 genetic variation on population-based differences in coronavirus etiology, our analysis is the first to identify ACE2 polymorphisms that may influence disease severity. Importantly, genetic variants that have been associated with ACE2 mRNA expression levels associated with disease severity. Further studies that analyze the expression altering effects of these polymorphisms in lung and cardiovascular tissue will be informative to fully understand their role in COVID-19 infectivity and disease severity.

In summary, in a cohort of patients with COVID-19 and pre-existing genotypic data, we found that six out of ten eQTL variants in ACE2, that are associated with altered ACE2 tissue expression, were associated with the need for hospitalization due to COVID-19. These results, . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 22, 2020. . https://doi.org/10.1101/2020.06.18.20135152 doi: medRxiv preprint although requiring replication in a validation cohort and in non-Caucasian populations, provide preliminary evidence of a genetic link between the ACE2 genotype and COVID-19 disease severity and suggest that the ACE2 genotype may inform COVID-19 risk stratification and need for more intense therapy.

The authors have no conflicts of interest to disclose. Dr. Malhotra is supported by NHLBI R01 HL142809, American Heart Association grant 18TPA34230025, and the Wild Family Foundation.

. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 22, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted June 22, 2020. . . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted June 22, 2020. . https://doi.org/10.1101/2020.06.18.20135152 doi: medRxiv preprint

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