ACE I/D polymorphism in Czech first-wave SARS-CoV-2-positive survivors

Insertion/deletion (I/D) polymorphisms of angiotensin-converting enzyme gene and their implications for susceptibility and severity of COVID-19: A systematic review and meta-analysis

The insertion or deletion polymorphisms of the angiotensin-converting enzyme gene (ACE I/D) have been the subject of significant research related to coronavirus disease 2019 (COVID-19). Despite this, the findings have remained uncertain and debatable. The aim of this study was to determine the associations between the ACE I/D polymorphisms and the susceptibility as well as the severity of COVID-19. A meta-analysis study (PROSPERO: CRD42022384562) was conducted by searching the articles published on PubMed, Scopus, and Embase as of May 15, 2023. Information regarding the impact of ACE I/D variant on the susceptibility to COVID-19 and its severity was collected and analyzed utilizing the Mantel-Haenszel method with a random effects model or fixed effects model, depending on the presence or absence of heterogeneity. Out of 3,335 articles, 21 articles were included, of which 13 investigated the association between ACE I/D and the risk of COVID-19 infection and 18 of them examined its influence on disease severity. The D allele of ACE increased risk of COVID-19 infection (OR: 1.41; 95%CI: 1.08-1.85; p-Egger: 0.0676; p-Heterogeneity: <0.001; p=0.0120), while ACE I allele (OR: 0.71; 95%CI: 0.54-0.93; p-Egger: 0.0676; p-Heterogeneity: <0.001; p=0.012) and II genotype (OR: 0.55; 95%CI: 0.34-0.87; p-Egger: 0.200; p-Heterogeneity: <0.001; p=0.011) decreased the risk of infection. Additionally, there was a notable association between the ACE ID genotype and an elevated likelihood of experiencing severe COVID-19 within the Asian population (OR: 1.46; 95%CI: 1.15-1.84; p-Egger: 0.092; p-Heterogeneity: 0.116; p=0.002). The presence of ACE I/D polymorphisms significantly influences the likelihood of being susceptible to and experiencing the severity of COVID-19.

Association of the polymorphism of the genes coding the renin-angiotensin system and the LZTFL1 gene with the severity and outcomes of SARS-CoV-2 infection

The aim of the study is to establish the association of variants of a number of genes involved in the reninangiotensin system with the severity of SARS-CoV-2 infection.

The study included 206 hospitalized patients with COVID-19: Group 1 – 99 patients with severe COVID-19; Group 2 ‒ 107 with moderate and mild forms of the disease.

Polymorphic variants of the ACE rs4646994, ACE2 rs2074192 rs2285666 and rs413031713 and LZTFL1 rs10490770 genes were analyzed using quantitative PCR with TaqMan probes (Primetech, Belarus) on a CFX96 thermocycler (Bio-Rad, USA). AGT rs699 and AGTR1 rs5186 gene variants were determined using a Rotor-Gene Q thermocycler (QIAGEN, Germany),  in accordance to the protocols of the manufacturer (Litekh, Russia).

We revealed that the genetic markers of the severe COVID-19 infection in the Belarusian patients are the heterozygous T/C genotype of the LZTFL1 rs10490770 variant, as well as the A-A haplotype of the ACE2 rs2074192 and rs2285666 loci, and the A-A-C allelic combination of the ACE2 rs2074192, rs2285666 and AGT rs699 genes. Genetic markers associated with mild/moderate severity of COVID-19 were also identified: heterozygous A/C genotype of the AGTR1 rs5186 variant,  G-G-T allelic combination at the ACE2 rs2074192 and rs2285666, AGT rs699 loci (among carriers of these gene variants,  the risk of severe disease is reduced).

The loci of the genes encoding the renin-angiotensin system – ACE2 rs2074192 and rs2285666, AGTR1 rs5186,  and the LZTFL1 rs10490770 genes, as well as allelic combinations between the ACE2 rs2074192, rs2285666 and AGT rs699 loci are informative markers for predicting the severity of COVID-19.

The Effect of Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism on the Severity and Death Rate of COVID-19 in Iranian Patients

The study was designed to assess the association of ACE I/D polymorphism with the severity and prognosis of COVID-19 in the Iranian population. Hence, 186 adult patients were categorized into three clinical groups based on the severity of COVID-19: 1) Outpatients or mildly symptomatic patients as control (n = 71); 2) Hospitalized patients or severe symptomatic cases (n = 53); 3) Inpatients led to ICU/death or critically ill patients needed mechanical ventilation (n = 62). The possible association of ACE I/D polymorphism with the risk of comorbidities and serum level of C-reactive protein was evaluated in two severe cases. The results showed that the frequency of D and I alleles are 69.35% and 30.65%, respectively, in the total population. The analysis of allelic frequencies via Fisher's exact test confirmed significantly higher frequency of D allele in both severe groups than that in the mild one, 78.31% in Hospitalized patients (OR = 2.56; 95% CI 1.46 to 4.46; p-value = 0.0011) and 74.19% in Inpatients led to ICU/death (OR = 2.04; 95% CI = 1.22 to 3.43; p-value = 0.0094) compared to 58.45% in Outpatients. The results of genotype proportions displayed an association between COVID-19 severity and DD genotype. Overall, our findings in Iranian patients supported the undeniable role of the DD genotype in the intensity of the disease, comparable to other populations. Furthermore, there is no definite evidence regarding the protective effect of the I allele in our inquiry.

Association of genetic polymorphisms with COVID-19 infection and outcomes: An updated meta-analysis based on 62 studies

Background

The relationship between genetic polymorphisms and coronavirus disease 2019 (COVID-19) remains to be inconsistent. This meta-analysis aimed to provide an updated evaluation of the role of genetic polymorphisms in the infection, severity and mortality of COVID-19 based on all available published studies.

Methods

A systematic search was performed using six databases: PubMed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and Wanfang. Summary odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) were used to calculate the genotypic comparison. All statistical analyses were conducted in Stata 12.0.

Results

A total of 62 studies with 19600 cases and 28899 controls was included in this meta-analysis. For COVID-19 infection, ACE Ins/Del polymorphism might be related with significantly decreased risk of COVID-19 infection under dominant, homozygote and allelic models. Meanwhile, the IFITM3 rs12252 and TMPRSS2 rs12329760 polymorphisms were significantly associated with the increased risk of COVID-19 infection under one or more models. Regarding COVID-19 severity, ACE2 rs2074192, ACE2 rs2106809, IFITM3 rs12252 and VDR rs1544410 polymorphisms might be related with significantly increased risk of COVID-19 severity in one or more models. Moreover, the analysis of TMPRSS2 rs2070788 indicated that a variant A allele decreased the risk of COVID-19 severity in recessive model. For COVID-19 mortality, the variant C allele of IFITM3 rs12252 polymorphism might be related with significantly increased risk of COVID-19 mortality under all genetic models.

Conclusions

This meta-analysis indicated that he infection, severity or mortality of COVID-19 were related to the above genetic polymorphisms, which might provide an important theoretical basis for understanding the clinical feature of COVID-19 disease.

Possible effect of OAS1 and TMPRSS6 but not DPP4 and ZNF335 polymorphisms on COVID-19 severity in the Czech population

OBJECTIVES

The acute respiratory syndrome, known as COVID-19, is characterised by high morbidity and increased mortality. Genetic factors may partially explain the differences in susceptibility to and severity of COVID-19.

METHODS

We have analysed common functional polymorphisms within the OAS1 (rs4767027), TMPRSS6 (rs855791), DPP4 (rs3788979), and ZNF335 (rs3848719) genes in SARS-CoV-2 positive subjects (n = 521, different disease severity) and in population controls (n = 2,559 subjects, COVID-19 status unknown).

RESULTS

Neither DPP4 nor ZNF335 were associated with disease susceptibility or severity in the Czech population in any of the models used for calculation. T allele carriers of the OAS1 polymorphism seem to be protective against symptomatic COVID-19 (p = 0.002 calculated for trend; asymptomatic, symptomatic, hospitalised). Similarly, within the TMPRSS6, minor TT homozygotes associated with lower plasma Fe concentrations were underrepresented in the overall patient group (p = 0.044; OR = 0.77, 95% CI: 0.59-0.99), and the difference was mainly driven by the severe COVID-19 subjects. In general, risky homozygotes of these two polymorphisms were less frequent than expected in the group of hospitalised COVID-19 survivors.

CONCLUSIONS

Common variants within OAS1 (rs4767027) and TMPRSS6 (rs855791) play some role in COVID-19 pathology in the Czech Caucasian population. Whether the depletion of minor allele carriers of these two variants is associated with increased COVID-19 mortality, needs to be analysed in an external confirmatory study.

Relationship between Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism and the Risk of COVID-19: A Meta-Analysis

INTRODUCTION

Research shows the correlation between angiotensin-converting enzyme (ACE) deletion and insertion (D/I) polymorphism and COVID-19 risk; yet, conclusive evidence is still lacking. Thus, a meta-analysis of relevant articles was performed to more accurately estimate the relationship of ACE I/D polymorphism with the risk of COVID-19. Material and Methods. Relevant literature from the PubMed database was systematically reviewed, and odds ratios (ORs) and associated 95% confidence intervals (CIs) were measured. Additionally, the metapackage from Stata version 15.0 was used for statistical analysis.

RESULTS

The meta-analysis eventually contained 8 studies, including 1362 COVID-19 cases and 4312 controls. Based on the data, the ACE I/D polymorphism did not show an association with COVID-19 risk (D vs. I: OR = 1.25, 95% CI = 0.96-1.64; DD vs. II: OR = 1.89, 95% CI = 0.95-3.74; DI vs. II: OR = 1.75, 95% CI = 0.92-3.31; dominant model: OR = 1.88, 95% CI = 0.99-3.53; and recessive model: OR = 1.24, 95% CI = 0.81-1.90). Further, subgroup analyses stratified based on case proved that the ACE D allele demonstrated an association with increasing risk of COVID-19 severity (D vs. I: OR = 1.64, 95% CI = 1.01-2.66; DD vs. II: OR = 4.62, 95% CI = 2.57-8.30; DI vs. II: OR = 3.07, 95% CI = 1.75-5.38; dominant model: OR = 3.74, 95% CI = 2.15-6.50; and recessive model: OR = 1.28, 95% CI = 0.46-3.51).

CONCLUSIONS

The ACE D allele was clearly related to an enhanced risk of COVID-19 severity. Hence, it is imperative to take into account the influence of genetic factors during the development of future vaccines.

Genetic polymorphisms of ACE1, ACE2, IFTM3, TMPRSS2 and TNFα genes associated with susceptibility and severity of SARS-CoV-2 infection: a systematic review and meta-analysis

BACKGROUND

Some human polymorphisms of ACE1, ACE2, IFITM3, TMPRSS2 and TNFα genes may have an effect on the susceptibility to SARS-CoV-2 infection and increase the risk to develop severe COVID-19. We conducted a systematic review of current evidence to investigate the association of genetic variants of these genes with the susceptibility to virus infection and patient prognosis.

METHODS

We systematically searched Medline, Embase and The Cochrane Library for articles published until May 2022, and included observational studies covering genetic association of ACE1, ACE2, IFITM3, TMPRSS2 and TNFα genes with COVID-19 susceptibility or prognosis. We evaluated the methodological quality of included studies, and pooled data as convenient in meta-analysis (MA). Odds ratio (OR) values and 95% confidence intervals were calculated.

RESULTS

We included 35 studies (20 on ACE, 5 each on IFITM3, TMPRSS2, TNFα), enrolling 21,452 participants, of them 9401 were COVID-19 confirmed cases. ACE1 rs4646994 and rs1799752, ACE2 rs2285666, TMPRSS2 rs12329760, IFITM3 rs12252 and TNFα rs1800629 were identifies as common polymorphisms. Our MA showed an association between genetic polymorphisms and susceptibility to SARS-CoV-2 infection for IFITM3 rs12252 CC (OR 5.67) and CT (OR 1.64) genotypes. Furthermore, MA uncovered that both ACE DD (OR 1.27) and IFITM3 CC (OR 2.26) genotypes carriers had a significantly increased risk of developing severe COVID-19.

DISCUSSION

These results provide a critical evaluation of genetic polymorphisms as predictors in SARS-CoV-2 infection. ACE1 DD and IFITM3 CC polymorphisms would lead to a genetic predisposition for severe lung injury in patients with COVID-19.

Genotype variation of ACE and ACE2 genes affects the severity of COVID-19 patients

OBJECTIVE

Genetic polymorphisms in ACE and ACE2 genes are involved in the RAS regulation of blood pressure and their activity may confer susceptibility to hypertension. In addition, they may play a role in SARS-CoV-2 pathogenesis and the severity of COVID-19. This study aims to determine the effect of genetic variations in the ACE (rs4331) and ACE2 (rs2074192) genes with hypertension comorbidity on the severity of COVID-19 in the Indonesian population.

RESULT

186 patients were enrolled and assigned into the COVID-19 group (n = 95) and non-COVID-19 group (n = 91) in this cross-sectional study. GG genotype frequency was dominant in ACE gene, but there were no significant differences between the groups (p = 0.163). The two groups had a significant difference (p = 0.000) for the CC genotype frequency (0,37 vs. 0.01) in the ACE2 gene. The proportion of women with COVID-19 is higher (51%), but men with hypertension had more severe symptoms (44%). Men with hypertension comorbidity, GG (ACE), and TT (ACE2) genotypes tended to have moderate-to-severe symptoms (25%). Similarly, women with hypertension as well as GG and CT genotypes tended to have moderate-to-severe symptoms (21%). We conclude that hypertension and mutations in the ACE (rs4331) and ACE2 (rs2074192) genes affect the severity of COVID-19.

A comprehensive review of ACE2, ACE1, TMPRSS2 and IFITM3 gene polymorphisms and their effect on the severity of COVID-19

Recent events have raised concerns about the outbreak of a pandemic by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An infection caused by a virus can provoke an inflammatory reaction, which can result in severe lung damage, failure of several organs, and death. The unique genetic makeup of each individual may be a component in the development of each of these responses. In this context, genetic variants of the genes linked to the invasion of the virus into the host's body can be analyzed. Various elements have a function in viral entry. ACE2 is used by SARS-CoV-2 as a receptor to enter the cell. TMPRSS2 is then responsible for cutting the virus into its components. In addition, lung damage occurs when there is an imbalance between ACE1 and ACE2. Another component that plays a significant role in virus penetration is called IFITM3, which is created as a reaction to interferon. This protein prevents viruses in the Coronaviridae family from entering cells. This study aimed to analyze DNA polymorphisms in the ACE2, ACE1, TMPRSS2, and IFITM3 genes. Findings showed certain polymorphisms appear to be associated with the severity of the disease, including respiratory, coronary, and neurological disorders. The results also indicated that certain polymorphisms were protective against this virus. Varying populations have a different frequency of high-risk polymorphisms, so different treatment and preventative techniques must be implemented. Additional population studies should be conducted in this region to reduce the incidence of COVID-19-related morbidity and mortality.

ABCA3 and LZTFL1 Polymorphisms and Risk of COVID-19 in the Czech Population

SARS-CoV-2 infection, which causes the respiratory disease COVID-19, has spread rapidly from Wuhan, China, since 2019, causing nearly 7 million deaths worldwide in three years. In addition to clinical risk factors such as diabetes, hypertension, and obesity, genetic variability is an important predictor of disease severity and susceptibility. We analyzed common polymorphisms within the LZTFL1 (rs11385942) and ABCA3 (rs13332514) genes in 519 SARS-CoV-2-positive subjects (164 asymptomatic, 246 symptomatic, and 109 hospitalized COVID-19 survivors) and a population-based control group (N?=?2,592; COVID-19 status unknown). Rare ABCA3 AA homozygotes (but not A allele carriers) may be at a significantly increased risk of SARS-CoV-2 infection [P?=?0.003; OR (95 % CI); 3.66 (1.47-9.15)]. We also observed a borderline significant difference in the genotype distribution of the LZTFL1 rs11385942 polymorphism (P?=?0.04) between the population sample and SARS-CoV-2-positive subjects. In agreement with previous studies, a nonsignificantly higher frequency of minor allele carriers was detected among hospitalized COVID-19 subjects. We conclude that a common polymorphism in the ABCA3 gene may be a significant predictor of susceptibility to SARS-CoV-2 infection.

Strong association between angiotensin-converting enzyme gene InDel polymorphism and COVID-19 diseases

Background and Objectives

The COVID-19 pandemic that emerged in China in late 2019 and spread rapidly around the world. There is evidence that COVID-19 infection can be influenced by genetic variations in the host. The aim of this study was to investigate the association between ACE InDel polymorphism and COVID-19 in Northern Cyprus.

Patients and methods

This study included 250 patients diagnosed with COVID-19 and 371 healthy controls. Genotyping for the ACE InDel gene polymorphism was performed by polymerase chain reaction.

Results

The frequency of ACE DD homozygotes was significantly increased in COVID-19 patients compared to the control group (p = 0.022). The difference in the presence of the D allele between the patient and control groups was statistically significant (57.2% and 50.67%, respectively, p < 0.05). Individuals with the genotype II were found to have a higher risk of symptomatic COVID-19 (p = 0.011). In addition, chest radiographic findings were observed more frequently in individuals with the genotype DD compared to individuals with the genotypes ID and II (p = 0.005). A statistically significant difference was found when the time of onset of symptoms for COVID-19 and duration of treatment were compared with participants' genotypes (p = 0.016 and p = 0.014, respectively). The time of onset of COVID-19 was shorter in individuals with the genotype DD than in individuals with the genotype II, while the duration of treatment was longer.

Conclusion

In conclusion, the ACE I/D polymorphism has the potential to predict the severity of COVID-19.

Single Nucleotide Variants (SNVs) of Angiotensin-Converting Enzymes (ACE1 and ACE2): A Plausible Explanation for the Global Variation in COVID-19 Prevalence

Background. Although it is common knowledge that the coronavirus disease of 2019 (COVID-19) and other viral infections have an uneven impact globally, the reasons for this are still indistinct. The absence of equivalent capacities worldwide in screening, testing, and reporting of cases is one of the ideas put forward to explain this discrepancy. The molecular developments are noteworthy, particularly the role played by single nucleotide polymorphisms (SNPs) in ACEs (ACE1 and ACE2). The virus can enter the host cell thanks to the transmembrane protein ACE2, which is a homolog of ACE1. Objectives. With a focus on the I/D genotype of ACE1 and the rs2285666 SNV of ACE2, we elucidated the prevalence of SNPs in ACE1 and ACE2 in various geographic locations. We examined the relationship between these SNPs and the global patterns of COVID-19 prevalence. Methods. 66 of the 127 articles obtained using PubMed, Google Scholar, and Google directly conformed to the search terms; geographical distribution of viral infections, the prevalence of COVID-19, ACE1, ACE2, SNPs, and prevalence of the DD genotype, and rs2285666. Results. The DD genotype of ACE1 and the rs2285666 SNV of ACE2 are vital in their gene expression and contribute greatly to viral disease susceptibility, development, and severity. There was generally a high prevalence of the DD genotype in Europe and America, where COVID-19 had a more devastating effect than in Asia and Africa. The prevalence of the SNV rs2285666 varied in the following order: East Asia> South Asia >America>Europe >Africa. However, there were conflicting agreements in the association of rs2285666 with COVID-19 susceptibility and prevalence. Conclusion. The ACE1 DD genotype and COVID-19 prevalence have been positively linked in a number of studies. The ACE2 rs2285666 SNV, however, has yielded no definitive results. To determine the relationship between these SNVs and COVID-19 incidence, more research is required.

Association of ACE ID, MTHFR C677T, and MIF-173GC variants with the clinical course of COVID-19 patients

The course of coronavirus disease-2019 (COVID-19) differs from person to person. The relationship between the genetic variations of the host and the course of COVID-19 has been a matter of interest. In this study, we investigated whether Angiotensin-Converting Enzyme (ACE) ID, Methylenetetrahydrofolate Reductase (MTHFR) C677T, and Macrophage Migration Inhibitory Factor (MIF)-173GC variants are risk factors for the clinical course of COVID-19 disease in Turkish patients. One hundred COVID-19 patients were included in the study. The diagnosis of COVID-19 was made using Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Chest Computed Tomography (CT). The patients were evaluated in 3 groups: intensive care, service, and outpatient treatment. ACE ID, MTHFR C677T, and MIF-173GC variants were genotyped by PCR-Restriction Fragment Length Polymorphism (RFLP) methods. When the genotype distribution between the groups was examined, it was found that the frequency of the ACE DD genotype and the D allele was higher in the intensive care group compared to the hospitalized and outpatient groups. MTHFR C677T CT genotype T allele and MIF-173GC, CC genotype C allele were more prevalent in the intensive care group compared to other groups. Patients with PCR-positive results had a higher MTHFR C677T C/C genotype and C allele. In CT-positive patients, the MTHFR C677T CT genotype and the MIF-173GC, G allele were more common. It is predicted that genetic predisposition may contribute to COVID-19 morbidity and mortality. Our results show that ACE ID, MTHFR C677T, and MIF-173GC variants affect the course of COVID-19 disease in the Turkish population.

Reductionist methodology and the ambiguity of the categories of race and ethnicity in biomedical research: an exploratory study of recent evidence

In this article, we analyse how researchers use the categories of race and ethnicity with reference to genetics and genomics. We show that there is still considerable conceptual "messiness" (despite the wide-ranging and popular debate on the subject) when it comes to the use of ethnoracial categories in genetics and genomics that among other things makes it difficult to properly compare and interpret research using ethnoracial categories, as well as draw conclusions from them. Finally, we briefly reconstruct some of the biases of reductionism to which geneticists (as well as other researchers referring to genetic methods and explanations) are particularly exposed to, and we analyse the problem in the context of the biologization of ethnoracial categories. Our work constitutes a novel, in-depth contribution to the debate about reporting race and ethnicity in biomedical and health research. First, we reconstruct the theoretical background assumptions about racial ontology which researchers implicitly presume in their studies with the aid of a sample of recent papers published in medical journals about COVID-19. Secondly, we use the typology of the biases of reductionism to the problem of biologization of ethnoracial categories with reference to genetics and genomics.

CD14 Polymorphism Is Not Associated with SARS-CoV-2 Infection in Central European Population

A 2021 in silico study highlighted an association between the CD14 polymorphism rs2569190 and increased susceptibility to SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19). The aim of our study was to confirm this finding. We analysed the CD14 polymorphism (C→T; rs2569190) in 516 individuals who tested positive for SARS-CoV-2, with differing disease severity (164 asymptomatic, 245 symptomatic, and 107 hospitalized). We then compared these patients with a sample from the general population consisting of 3,037 individuals using a case-control study design. In comparison with carriers of the C allele, TT homozygotes accounted for 21.7 % of controls and 20.5 % in SARS-CoV-2-positive individuals (P = 0.48; OR; 95 % CI - 0.92; 0.73-1.16). No significant differences in the distribution of genotypes were found when considering co-dominant and recessive genetic models or various between-group comparisons. The CD14 polymorphism is unlikely to be an important predictor of COVID-19 in the Caucasian population in Central Europe.

A haemochromatosis-causing HFE mutation is associated with SARS-CoV-2 susceptibility in the Czech population

BACKGROUND

Coronavirus disease (COVID-19), which is caused by the SARS-CoV-2 virus, has become a global pandemic. While susceptibility to COVID-19 is subject to several external factors, including hypertension, BMI, and the presence of diabetes, it is also genetically determined to a significant extent. Infectious agents require iron (Fe) for proper functioning. Carriers of mutations resulting in increased iron concentrations are understood to be at increased risk of COVID-19.

METHODS

We examined HFE genotypes associated with hereditary haemochromatosis (rs1800562 and rs1799945 SNPs) in 617 COVID-19 patients (166 asymptomatic, 246 symptomatic and 205 hospitalised survivors) and 2 559 population-based controls.

RESULTS

We found a higher frequency of the minor allele (Tyr282) of the rs1800562 polymorphism (P < 0.002) in patients compared to controls (8.5 % vs 5.5 %). Non-carriers of the minor allele were protected against SARS-Cov-2 infection (OR, 95 %CI; 0.59, 0.42-0.82). The frequency of minor allele carriers was almost identical across asymptomatic, symptomatic, and hospitalised survivors. The rs1799945 variant did not affect disease severity and its occurrence was almost identical in patients and controls (P between 0.58 and 0.84).

CONCLUSIONS

In conclusion, our results indicate that presence of the rs1800562 minor allele, which is associated with hereditary haemochromatosis (thus increased levels of plasma Fe), increases susceptibility to SARS-CoV-2.

Angiotensin Converting Enzyme 1 Polymorphisms and Lipid Profile in Mexican Patients With COVID-19

BACKGROUND/AIM

Renin-angiotensin system (RAS) is present in a diverse type of cells and plays an important role in lung physiology and pathophysiology. Angiotensin converting enzymes (ACE) are part of the RAS system. There are still controversies about the association of I/D polymorphisms of ACE1 with COVID-19 severity. The goal of the study was to determine whether there is an association of the I/D polymorphism with severity of COVID-19 in Mexican patients.

PATIENTS AND METHODS

The study included voluntary participants: 53 healthy individuals negative to RT-PCR COVID-19 (control), and 165 patients positive to COVID-19. Severity was defined by the need of hospitalization, invasive ventilation, shock, or multiple organ failure. The patient group consisted of 28 asymptomatic, 82 with mild, and 55 with severe COVID-19. I/D polymorphism was determined by PCR. Rutinary laboratory tests were performed in all the participants.

RESULTS

DD polymorphism was significantly associated with severe COVID-19, independently of comorbidities, or any other variable. Receiver operator characteristic curves demonstrated association of low total cholesterol, low high-density lipoproteins, and high c-reactive protein with severity of COVID-19.

CONCLUSION

The DD polymorphism was associated with the course of the infection and severity of COVID-19 in a sample of Mexican patients.

Association investigations between ACE1 and ACE2 polymorphisms and severity of COVID-19 disease

Due to the unique affinity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to the angiotensin-converting enzyme 2 (ACE2) receptor in patients, the foremost recent evidence indicated that ACE1 and ACE2 polymorphisms could affect the susceptibility of individuals to SARS-CoV-2 infection and also the disease outcome. Here, we aimed to assess the possible association between two polymorphisms and the severity of disease in patients. In the present study, 146 patients with COVID-19 who were admitted to the Mazandaran University of Medical Sciences hospitals between March 2020 and July 2020 were enrolled in this case-control study. The patients were divided into four groups based on clinical symptoms and severity of the diseases (mild, moderate, severe, and critical). After DNA extraction, the ACE gene I/D polymorphism (rs4646994) and ACE2 gene polymorphism (rs2285666) were genotyped using Gap-PCR and PCR-RFLP techniques, respectively. Then, five samples from each obtained genotype were confirmed by Sanger sequencing technique. Data were analyzed with SAS software version 9.1 using appropriate statistical procedures. The ACE gene I/D polymorphism (rs4646994) genotypes were classified into three types: I/I, I/D, and D/D. Our finding indicated that the prevalence of ACE1 D/D genotype was significantly higher in severe and critical COVID-19 patients (P = 0.0016). Additionally, the analysis revealed a remarkable association between rs4646994 SNP and the HB and ESRI levels in patients (P < 0.05). Although the ACE2 rs2285666 SNP was not related to the severity of disease, this variant was significantly associated with ALT, ESRI, and P. These results provide preliminary evidence of a genetic association between the ACE-D/D genotype and the D allele of ACE1 genotype and the disease severity. Therefore, our findings might be useful for identifying the susceptible population groups for COVID-19 therapy.

Polymorphisms in ACE1, TMPRSS2, IFIH1, IFNAR2, and TYK2 Genes Are Associated with Worse Clinical Outcomes in COVID-19

Although advanced age, male sex, and some comorbidities impact the clinical course of COVID-19, these factors only partially explain the inter-individual variability in disease severity. Some studies have shown that genetic polymorphisms contribute to COVID-19 severity; however, the results are inconclusive. Thus, we investigated the association between polymorphisms in ACE1, ACE2, DPP9, IFIH1, IFNAR2, IFNL4, TLR3, TMPRSS2, and TYK2 and the clinical course of COVID-19. A total of 694 patients with COVID-19 were categorized as: (1) ward inpatients (moderate symptoms) or patients admitted at the intensive care unit (ICU; severe symptoms); and (2) survivors or non-survivors. In females, the rs1990760/IFIH1 T/T genotype was associated with risk of ICU admission and death. Moreover, the rs1799752/ACE1 Ins and rs12329760/TMPRSS2 T alleles were associated with risk of ICU admission. In non-white patients, the rs2236757/IFNAR2 A/A genotype was associated with risk of ICU admission, while the rs1799752/ACE1 Ins/Ins genotype, rs2236757/IFNAR2 A/A genotype, and rs12329760/TMPRSS2 T allele were associated with risk of death. Moreover, some of the analyzed polymorphisms interact in the risk of worse COVID-19 outcomes. In conclusion, this study shows an association of rs1799752/ACE1, rs1990760/IFIH1, rs2236757/IFNAR2, rs12329760/TMPRSS2, and rs2304256/TYK2 polymorphisms with worse COVID-19 outcomes, especially among female and non-white patients.

The association of ACE I/D polymorphism with the severity of COVID-19 in Iranian patients: A case-control study

BACKGROUND

Since the beginning of the COVID-19 pandemic, researchers have tried to find the reason behind the variety of the symptoms and disease severity among patients. It seems that genetic background may contribute in severity of this infection. The renin-angiotensin system (RAS) is involved in the pathogenesis of COVID-19. An Insertion/Deletion (I/D) polymorphism in the ACE1 gene may explain the genetic risk for disease severity.

METHODS

We genotyped 251 COVID-19 patients: 151 patients with mild or asymptomatic disease compared with 100 patients with severe to critical illness (without any comorbidities for the disease severity).

RESULTS

There was a significant association between the ACE1 DD genotype and disease severity (p-value = 1 × 10-2; OR = 2.004, 95%CI = 1.147-3.499) and our results showed that it was inherited under recessive or codominant inheritance patterns. Also, the I allele showed a protective role against the severe form of COVID-19 disease (p-value = 1 × 10-4).

CONCLUSION

We concluded that ACE1 DD genotype can predict the risk of severe form of COVID-19 infection in the absence of known comorbidities as disease severity risk factors. Further studies with larger sample sizes in other populations are still needed to clarify the role of ACE I/D polymorphism in SARS-CoV-2 infection severity.

Systematic review and meta-analysis of human genetic variants contributing to COVID-19 susceptibility and severity

The COVID-19 pandemic has spawned global health crisis of unprecedented magnitude, claiming millions of lives and pushing healthcare systems in many countries to the brink. Among several factors that contribute to an increased risk of COVID-19 and progression to exacerbated manifestations, host genetic landscape is increasingly being recognized as a critical determinant of susceptibility/resistance to infection and a prognosticator of clinical outcomes in infected individuals. Recently, several case-control association studies investigated the influence of human gene variants on COVID-19 susceptibility and severity to identify the culpable mutations. However, a comprehensive synthesis of the recent advances in COVID-19 host genetics research was lacking, and the inconsistent findings of the association studies required reliable evaluation of the strength of association with greater statistical power. In this study, we embarked on a systematic search of all possible reports of genetic association with COVID-19 till April 07, 2022, and performed meta-analyses of all the genetic polymorphisms that were examined in at least three studies. After identifying a total of 84 studies that investigated the association of 130 polymorphisms in 61 genes, we performed meta-analyses of all the eligible studies. Seven genetic polymorphisms involving 15,550 cases and 444,007 controls were explored for association with COVID-19 susceptibility, of which, ACE1 I/D rs4646994/rs1799752, APOE rs429358, CCR5 rs333, and IFITM3 rs12252 showed increased risk of infection. Meta-analyses of 11 gene variants involving 6702 patients with severe COVID-19 and 8640 infected individuals with non-severe manifestations revealed statistically significant association of ACE2 rs2285666, ACE2 rs2106809, ACE2 rs2074192, AGTR1 rs5186, and TNFA rs1800629 with COVID-19 severity. Overall, our study presents a synthesis of evidence on all the genetic determinants implicated in COVID-19 to date, and provides evidence of correlation between the above polymorphisms with COVID-19 susceptibility and severity.

Genetics of COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome: a systematic review

COVID‐19 and ME/CFS present with some similar symptoms, especially physical and mental fatigue. In order to understand the basis of these similarities and the possibility of underlying common genetic components, we performed a systematic review of all published genetic association and cohort studies regarding COVID‐19 and ME/CFS and extracted the genes along with the genetic variants investigated. We then performed gene ontology and pathway analysis of those genes that gave significant results in the individual studies to yield functional annotations of the studied genes using protein analysis through evolutionary relationships (PANTHER) VERSION 17.0 software. Finally, we identified the common genetic components of these two conditions. Seventy‐one studies for COVID‐19 and 26 studies for ME/CFS were included in the systematic review in which the expression of 97 genes for COVID‐19 and 429 genes for ME/CFS were significantly affected. We found that ACE, HLA‐A, HLA‐C, HLA‐DQA1, HLA‐DRB1, and TYK2 are the common genes that gave significant results. The findings of the pathway analysis highlight the contribution of inflammation mediated by chemokine and cytokine signaling pathways, and the T cell activation and Toll receptor signaling pathways. Protein class analysis revealed the contribution of defense/immunity proteins, as well as protein‐modifying enzymes. Our results suggest that the pathogenesis of both syndromes could involve some immune dysfunction.

Association of ACE1 I/D rs1799752 and ACE2 rs2285666 polymorphisms with the infection and severity of COVID-19: A meta-analysis

BACKGROUND

ACE1 I/D rs1799752 and ACE2 rs2285666 genetic polymorphisms could play a critical role in altering the clinical outcomes of SARS-CoV-2. The findings of previous studies remained inconclusive. This meta-analysis was performed to evaluate the association and provide a more reliable outcome.

METHODS

This study was completed following the updated recommendations of PRISMA using RevMan 5.4.1 statistical software.

RESULTS

A total of 11 studies with 950 severe cases and 1573 non-severe cases with COVID-19 infection were included. Pooled analysis showed that ACE1 I/D polymorphism was correlated with the severity of SARS-CoV-2 in the DD genotype and D allele for the fixed-effects model (OR:1.27 and OR:1.17). Besides, codominant 3, recessive, and allele models were associated with the severity of the fixed-effects model (OR:1.35, OR:1.37, and OR:1.20) in Caucasian ethnicity. ACE2 rs2285666 was linked with the severity in codominant 3 (OR:2.63, for both random- and fixed effects-models), overdominant (OR:1.97, for random-effects model and OR:1.97, for fixed effects-model), and recessive model (OR:0.41 for fixed- and random-effects model). Allele model of rs2285666 showed a significant association in the fixed-effects model (OR:1.61).

CONCLUSION

Our present meta-analysis suggests that ACE1 I/D rs1799752 and ACE2 rs2285666 variants may enhance the severity in SARS-CoV-2 infected patients. Future studies are warranted to verify our findings.

Global distribution of ACE1 (rs4646994) and ACE2 (rs2285666) polymorphisms associated with COVID-19: A systematic review and meta-analysis

BACKGROUND

Recent studies emphasize the significant impact of the renin-angiotensin aldosterone system (RAAS) as a risk factor associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, according to the literature, the effect of rs4646994 and rs2285666 polymorphisms on susceptibility and progression to severe clinical outcomes is still controversial. Our aim was to investigate the effect of polymorphisms such as rs4646994 and rs2285666 on susceptibility to coronavirus disease-2019 (COVID-19).

METHODS

We conducted a comprehensive literature search using databases such as ISI Web of Science, PubMed, Scopus, and Google Scholar to retrieve studies on the effect of two polymorphisms (rs4646994 and rs2285666) of the angiotensin-converting enzyme (ACE) gene on COVID-19. Finally, the effect of each polymorphism on SARS-CoV-2 infection was measured based on the odds ratio with 95% confidence intervals.

RESULTS

Analysis of the rs4646994 polymorphism showed that the frequency of the D allele in patients infected with COVID-19 was higher than that the I allele. Moreover, the authors found that the DD genotype increased the risk of severe disease by 1.7-fold in Asian population, whereas, this was not the case in the Western population. However, the rs4646994 II genotype plays a protective role against COVID-19 in Western countries. In the case of the rs2285666 polymorphism based on patient ethnicity, the C allele had the highest frequency. Interestingly, in people harboring the GG and TT genotypes, the risk of progression to severe disease significantly increased, while people with genotypes such as GA, AA and CC seem to be more resistant to severe Covid-19.

CONCLUSIONS

Based on geographical region, the rs4646994 DD genotype may be considered as a predictive biomarker to identify the susceptibility of human to SARS-CoV-2 infection and severe COVID-19 outcomes. We also concluded that individuals with GG and TT genotypes are significantly more susceptible to severe outcomes of disease, while conversely, individuals with GA, AA, and CC genotypes are less susceptible to severe COVID-19.

The role of ACE1 I/D and ACE2 polymorphism in the outcome of Iranian COVID-19 patients: A case-control study

Background: Since the beginning of the pandemic of coronavirus disease 2019 (COVID-19), many countries have experienced a considerable number of COVID-19 cases and deaths. The etiology of a broad spectrum of symptoms is still debated. Host genetic variants might also significantly influence the outcome of the disease. This study aimed to evaluate the association of angiotensin-converting enzyme (ACE1) gene Insertion/Deletion (I/D) polymorphism (rs1799752) and ACE2 gene rs1978124 single nucleotide polymorphism with the COVID-19 severity.

Methods: This study was conducted on 470 COVID-19 patients and a control group of 56 healthy individuals across several major cities in Iran. The blood sample and clinical data were collected from the participants, and their ACE1 I/D and ACE2 rs1978124 polymorphisms were determined using polymerase chain reaction and PCR-RFLP, respectively. Serum levels of C-reactive protein (CRP), interleukin 6 (IL-6), and ACE1 were measured in the blood samples.

Results: We found that the ACE1 DD genotype frequency was inversely correlated with the risk of intubation (p = 0.017) and mortality in COVID-19 patients (p = 0.049). Even after adjustment, logistic regression demonstrated that this significant inverse association remained constant for the above variables at odds ratios of (OR) = 0.35 and Odds Ratio = 0.49, respectively. Also, in the expired (p = 0.042) and intubated (p = 0.048) groups with II + ID genotypes, the mean level of CRP was significantly higher than in the DD genotype group. Furthermore, in both intubated and expired groups, the mean serum level of ACE1 was higher compared with non-intubated and survived groups with II or II + ID genotypes. The results also indicated that ACE2 rs1978124 TT + CT genotypes in females have a significant positive role in susceptibility to COVID-19; however, in females, the TT + CT genotypes had a protective effect (OR = 0.098) against the severity of COVID-19.

Conclusion: These findings suggest that ACE1 I/D and ACE2 rs1978124 polymorphism could potentially influence the outcome of COVID-19 in the Iranian population.

Genetic polymorphisms associated with susceptibility to COVID-19 disease and severity: A systematic review and meta-analysis

Although advanced age and presence of comorbidities significantly impact the variation observed in the clinical symptoms of COVID-19, it has been suggested that genetic variants may also be involved in the disease. Thus, the aim of this study was to perform a systematic review with meta-analysis of the literature to identify genetic polymorphisms that are likely to contribute to COVID-19 pathogenesis. Pubmed, Embase and GWAS Catalog repositories were systematically searched to retrieve articles that investigated associations between polymorphisms and COVID-19. For polymorphisms analyzed in 3 or more studies, pooled OR with 95% CI were calculated using random or fixed effect models in the Stata Software. Sixty-four eligible articles were included in this review. In total, 8 polymorphisms in 7 candidate genes and 74 alleles of the HLA loci were analyzed in 3 or more studies. The HLA-A*30 and CCR5 rs333Del alleles were associated with protection against COVID-19 infection, while the APOE rs429358C allele was associated with risk for this disease. Regarding COVID-19 severity, the HLA-A*33, ACE1 Ins, and TMPRSS2 rs12329760T alleles were associated with protection against severe forms, while the HLA-B*38, HLA-C*6, and ApoE rs429358C alleles were associated with risk for severe forms of COVID-19. In conclusion, polymorphisms in the ApoE, ACE1, TMPRSS2, CCR5, and HLA loci appear to be involved in the susceptibility to and/or severity of COVID-19.

Genetic polymorphisms of ACE1, ACE2, and TMPRSS2 associated with COVID-19 severity: A systematic review with meta-analysis

Novel coronavirus disease 2019 (COVID-19) poses a global threat, due to its fluctuating frequency and lethality. Published data revealed associations of COVID-19 susceptibility and severity with host genetic polymorphisms in renin-angiotensin-aldosterone system (RAAS)-related genes including angiotensin-converting enzyme (ACE)1, ACE2, and transmembrane protease (TMPRSS)2. However, the findings remain inconclusive. Accordingly, we aimed to clarify associations of genetic variants in those genes with COVID-19 susceptibility and severity using a systematic review with meta-analysis. From inception through 1 July 2021, a literature search was performed using PubMed, Scopus, Web of Science, and Cochrane Library databases. Allelic distributions for each polymorphism were calculated as pooled odds ratios (OR) with 95% confidence intervals (CI) to assess the strength of association. A total of 3333 COVID-19 patients and 5547 controls from 11 eligible studies were included. From a systematic review, ACE1 rs1799752, ACE1 rs4646994, ACE2 rs2285666, and TMPRSS2 rs12329760 were identified as common polymorphisms of RAAS-related genes. Meta-analysis showed a significant association between TMPRSS2 rs12329760 C-allele and an increased risk of developing severe COVID-19 (OR = 1.32, 95% CI: 1.01, 1.73). Likewise, additional meta-analyses uncovered that both ACE1 rs4646994 DD-genotype and ACE2 rs2285666 GG-genotype carriers had a significantly increased risk of developing severe COVID-19 (OR = 2.06, 95% CI: 1.45, 2.93; OR = 2.14, 95% CI: 1.26, 3.66; respectively). Genetic polymorphisms of ACE1 rs4646994 DD-genotype, ACE2 rs2285666 GG-genotype, and TMPRSS2 rs12329760 CC-genotype and C-allele may serve as predictive models of COVID-19 severity.

The association of ACE1, ACE2, TMPRSS2, IFITM3 and VDR polymorphisms with COVID-19 severity: A systematic review and meta-analysis

Genes involved in the regulation of viral recognition and its entry into a host cell have been identified as candidates for genetic association studies on COVID-19 severity. Published findings on the effects of polymorphisms within ACE1, ACE2, TMPRSS2, IFITM3 and VDR genes remained inconclusive, so we conducted a systematic review and meta-analysis in order to elucidate their potential involvement in the genetic basis underlying the severity of COVID-19 and/or an outcome of SARS-CoV-2 infection. Identification of potentially eligible studies was based on PubMed, Scopus and Web of Science database search. Relevant studies (n=29) with a total number of 8247 SARS-CoV-2-positive participants were included in qualitative synthesis, while results of 21 studies involving 5939 were pooled in meta-analysis. Minor allele I of rs1799752 located within ACE1 was identified as a protective variant against severe COVID-19, while its effect on mortality rate was opposite. Similarly, minor allele A of ACE2 polymorphism, rs2285666, was found to associate with a decreased risk of severe COVID-19 (P = 0.003, OR = 0.512, 95 % CI = 0.331-0.793). Statistical significance was also seen for the association between COVID-19 severity and rs12329760 located within TMPRSS2. Our results did not support the supposed association of rs12252 in IFITM3 and polymorphisms within VDR with disease severity. We conclude that genetic variants within ACE1, ACE2 and TMPRSS2 may be potential biomarkers of COVID-19 severity, which needs to be further confirmed in a larger set of studies.

IFITM3, FURIN, ACE1, and TNF-α Genetic Association With COVID-19 Outcomes: Systematic Review and Meta-Analysis

Human polymorphisms may contribute to SARS-CoV-2 infection susceptibility and COVID-19 outcomes (asymptomatic presentation, severe COVID-19, death). We aimed to evaluate the association of IFITM3, FURIN, ACE1, and TNF-α genetic variants with both phenotypes using meta-analysis. The bibliographic search was conducted on the PubMed and Scielo databases covering reports published until February 8, 2022. Two independent researchers examined the study quality using the Q-Genie tool. Using the Mantel–Haenszel weighted means method, odds ratios were combined under both fixed- and random-effect models. Twenty-seven studies were included in the systematic review (five with IFITM3, two with Furin, three with TNF-α, and 17 with ACE1) and 22 in the meta-analysis (IFITM3 n = 3, TNF-α, and ACE1 n = 16). Meta-analysis indicated no association of 1) ACE1 rs4646994 and susceptibility, 2) ACE1 rs4646994 and asymptomatic COVID-19, 3) IFITM3 rs12252 and ICU hospitalization, and 4) TNF-α rs1800629 and death. On the other hand, significant results were found for ACE1 rs4646994 association with COVID-19 severity (11 studies, 692 severe cases, and 1,433 nonsevere controls). The ACE1 rs4646994 deletion allele showed increased odds for severe manifestation (OR: 1.45; 95% CI: 1.26–1.66). The homozygous deletion was a risk factor (OR: 1.49, 95% CI: 1.22–1.83), while homozygous insertion presented a protective effect (OR: 0.57, 95% CI: 0.45–0.74). Further reports are needed to verify this effect on populations with different ethnic backgrounds.

Systematic Review Registration: https://www.crd.york.ac.uk/prosperodisplay_record.php?ID=CRD42021268578, identifier CRD42021268578

Severity of coronavirus disease 19: Profile of inflammatory markers and ACE (rs4646994) and ACE2 (rs2285666) gene polymorphisms in Iraqi patients

Susceptibility to coronavirus disease 2019 (COVID-19) and disease severity has recently been associated with inflammatory markers and genetic polymorphisms of ACE (angiotensin-converting enzyme) and ACE2 genes, but the evidence has been inconclusive. This case-control study (99 COVID-19 patients and 96 controls) sought to assess the significance of age, C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) and SARS-CoV-2 RT-PCR cycle threshold (Ct) in severity of COVID-19. Besides, two variants of ACE and ACE2 genes (rs4646994 and rs2285666, respectively) were analyzed to determine their role in COVID-19 susceptibility and/or disease severity. Results revealed that age, CRP and NLR were significantly elevated in severe cases compared to moderate cases, while RT-PCR Ct value was significantly decreased. Allele and genotypes of both variants were not associated with COVID-19 risk, with the exception of rs2285666 A allele. It showed a significantly higher frequency in female patients than in female controls (probability = 0.041). In conclusion, the study indicated the role of age, CRP, NLR and SARS-CoV-2 RT-PCR Ct in susceptibility to COVID-19 severity. However, analysis of the ACE and ACE2 gene variants (rs4646994 and rs2285666, respectively) showed that the two variants were not associated with the risk of developing COVID-19.

Viral and Host Genetic and Epigenetic Biomarkers Related to SARS-CoV-2 Cell Entry, Infection Rate, and Disease Severity

The rapid spread of COVID-19 outbreak lead to a global pandemic declared in March 2020. The common features of corona virus family helped to resolve structural characteristics and entry mechanism of SARS-CoV-2. However, rapid mutagenesis leads to the emergence of new strains that may have different reproduction rates or infectivity and may impact the course and severity of the disease. Host related factors may also play a role in the susceptibility for infection as well as the severity and outcomes of the COVID-19. We have performed a literature and database search to summarize potential viral and host-related genomic and epigenomic biomarkers, such as genetic variability, miRNA, and DNA methylation in the molecular pathway of SARS-CoV-2 entry into the host cell, that may be related to COVID-19 susceptibility and severity. Bioinformatics tools may help to predict the effect of mutations in the spike protein on the binding to the ACE2 receptor and the infectivity of the strain. SARS-CoV-2 may also target several transcription factors and tumour suppressor genes, thus influencing the expression of different host genes and affecting cell signalling. In addition, the virus may interfere with RNA expression in host cells by exploiting endogenous miRNA and its viral RNA. Our analysis showed that numerous human miRNA may form duplexes with different coding and non-coding regions of viral RNA. Polymorphisms in human genes responsible for viral entry and replication, as well as in molecular damage response and inflammatory pathways may also contribute to disease prognosis and outcome. Gene ontology analysis shows that proteins encoded by such polymorphic genes are highly interconnected in regulation of defense response. Thus, virus and host related genetic and epigenetic biomarkers may help to predict the course of the disease and the response to treatment.

Effects of selected inherited factors on susceptibility to SARS-CoV-2 infection and COVID-19 progression

Genetic predispositions may influence geographical and interethnic differences in COVID-19 prevalence and mortality in affected populations. Of the many genes implicated in COVID-19 progression, a substantial number have no direct functional link on virus transfer/viability or on the host immune system. To address this knowledge deficit, a large number of in silico studies have recently been published. However, the results of these studies often contradict the findings of studies involving real patients. For example, the ACE2 has been shown to play an important role in regulating coronavirus entry into cells, but none of its variations have been directly associated with COVID-19 susceptibility or severity. Consistently was reported that increased risk of COVID-19 is associated with blood group A and with the APOE4 allele. Among other genes with potential impacts are the genes for CCR5, IL-10, CD14, TMPRSS2 and angiotensin-converting enzyme. Variants within the protein-coding genes OAS1 and LZTFL1 (transferred to the human genome from Neanderthals) are understood to be among the strongest predictors of disease severity. The intensive research efforts have helped to identify the genes and polymorphisms that contribute to SARS-CoV-2 infection and COVID-19 severity.

Angiotensin-Converting Enzyme (ACE) 1 Gene Polymorphism and Phenotypic Expression of COVID-19 Symptoms

The renin–angiotensin–aldosterone system (RAAS) appears to play an important role in SARS-CoV-2 infection. Polymorphisms within the genes that control this enzymatic system are candidates for elucidating the pathogenesis of COVID-19, since COVID-19 is not only a pulmonary disease but also affects many organs and systems throughout the body in multiple ways. Most striking is the fact that ACE2, one of the major components of the RAAS, is a prerequisite for SARS-COV-2 infection. Recently, we and other groups reported an association between a polymorphism of the ACE1 gene (a homolog of ACE2) and the phenotypic expression of COVID-19, particularly in its severity. The ethnic difference in ACE1 insertion (I)/deletion (D) polymorphism seems to explain the apparent difference in mortality between the West and East Asia. The purpose of this review was to further evaluate the evidence linking ACE1 polymorphisms to COVID-19. We searched the Medline database (2019–2021) for reference citations of relevant articles and selected studies on the clinical outcome of COVID-19 related to ACE1 I/D polymorphism. Although the numbers of patients are not large enough yet, most available evidence supports the notion that the DD genotype adversely influences COVID-19 symptoms. Surprisingly, small studies conducted in several countries yielded opposite results, suggesting that the ACE1 II genotype is a risk factor. This contradictory result may be the case in certain geographic areas, especially in subgroups of patients. It may also be due to interactions with other genes or to yet unexplained biochemical mechanisms. According to our hypothesis, such candidates are genes that are functionally involved in the pathophysiology of COVID-19, can act in concert with the ACE1 DD genotype, and that show differences in their frequency between the West and East Asia. For this, we conducted research focusing on Alu-related genes. The current study on the ACE1 genotype will provide potentially new clues to the pathogenesis, treatment, and diagnosis of SARS-CoV-2 infections.

Host genetic factors determining COVID-19 susceptibility and severity

The COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) poses an unprecedented challenge to humanity. SARS-CoV-2 infections range from asymptomatic to severe courses of COVID-19 with acute respiratory distress syndrome (ARDS), multiorgan involvement and death. Risk factors for disease severity include older age, male sex, increased BMI and pre-existing comorbidities. Ethnicity is also relevant to COVID-19 susceptibility and severity. Host genetic predisposition to COVID-19 is now increasingly recognized and whole genome and candidate gene association studies regarding COVID-19 susceptibility have been performed. Several common and rare variants in genes related to inflammation or immune responses have been identified. We summarize research on COVID-19 host genetics and compile genetic variants associated with susceptibility to COVID-19 and disease severity. We discuss candidate genes that should be investigated further to understand such associations and provide insights relevant to pathogenesis, risk classification, therapy response, precision medicine, and drug repurposing.