ABSTRACT
Background/Objectives: The severity of the symptoms of coronavirus disease 2019 (COVID-19) has been associated to age, comorbidity, and male sex. Besides virus characteristics, host genetic factors influence the infection outcome. Different genome-wide association studies and meta-analyses investigated the contribution of common variants, whereas the role of rare variants just started to be elucidated. Our goal is to determine the contribution of rare variants to the development of severe COVID-19 in the Italian population. Method(s): We compared the genetic background of 215 severe COVID-19 patients with 1764 individuals from the general population. Rare variants (minor allele frequency <1%) from wholeexome sequencing data were retrieved using a bioinformatics variant discovery pipeline. We tested the impact of rare variants (classified according to their predicted effect on the gene product) both using a burden test design, and an iterative machine learning (ML) approach. Result(s): We identified a total of 690,000 rare variants in the entire examined population. Among them, 250 were associated with COVID-19 severity at a nominal P < 0.05. Gene-based burden test revealed a gene with an excess of loss-of-function mutations at P < 0.05. Finally, the ML approach, analysing all the 690,000 rare variants, identified the best combination of variants that is able to predict COVID-19 severity in our cohort. Conclusion(s): Our work provides new insights on the genetic signature of COVID-19 in the Italian population. The most informative rare variants could be exploited to define individuals' risk profiles to COVID-19 severity for the Italian population.
ABSTRACT
BACKGROUND: There are sex differences in vulnerability to Coronavirus disease 2019 (COVID-19). The coronavirus S protein mediates viral entry into target cells employing the host cellular serine protease TMPRSS2 for S-protein priming. The TMPRSS2 gene expression is responsive to androgen stimulation and it could partially explain sex differences. We hypothesized that men chronically exposed to 5-alpha reductase inhibitors (5ARIs) for benign prostate hyperplasia (BPH) have a lower risk of hospitalization for COVID-19. METHODS: This is a population-based case-control study on consecutive patients positive for SARS-CoV-2 virus who required hospitalization for COVID-19 (cases), age-matched to beneficiaries of the Lombardy Regional Health Service (controls). Data were collected by two high-volume COVID-19 regional centers of Lombardy (Italy). The primary outcome was to compare the prevalence of patients chronically exposed to 5ARIs, who required hospitalization for COVID-19, with the one of controls. RESULTS: Overall, 943 males were enrolled;45 (4.77%) were exposed to 5ARI. COVID-19 patients aged >55 years under 5ARI treatment were significantly less than expected on the basis of the prevalence of 5ARI treatment among age-matched controls (5.57 vs. 8.14%;p=0.0083, 95%CI=0.75-3.97%). This disproportion was higher for men aged >65 (7.14 vs. 12.31%;p=0.0001, 95%CI=2.83-6.97%). Eighteen 5ARIs-patients died;the mean age of men who died was higher than those who did not: 75.98+/-9.29 vs. 64.78+/-13.57 (p<0.001). Cox-regression and multivariable models did not show correlation between 5ARIs exposure and protection against intensive care unit admission/death. CONCLUSIONS: Men exposed to 5ARIs might be less vulnerable to severe COVID-19, supporting its use in disease prophylaxis.