COVID-19: Why has Africa been “Spared”?

After more than one year of the COVID-19 pandemic, the disaster predicted in Africa by experts has not occurred. The present review aimed to discuss factors which may have played an important role in this low incidence. The analysis of data provided by the WHO database and the ECDC (European Center for Disease Prevention and Control) was made. Using explicit reasoning and existing data, the most significant factors were listed and discussed. We found that Africa had the lowest percentage of COVID-19 cases per population (0.33%) and various factors such as rapid reactions, effective preventive measures, demographics, the impact of previous epidemics, genetic and immunity factors may have played an important role in this low incidence of the pandemic in Africa. It appears that Africa is globally less affected. Most of the factors discussed may have played an important role, but the genetic hypothesis and the potential undercount of cases, less studied to date, should be investigated.

Genetic Hypothesis and Pharmacogenetics Side of Renin-Angiotensin-System in COVID-19

The importance of host genetics and demography in coronavirus disease 2019 (COVID-19) is a crucial aspect of infection, prognosis and associated case fatality rate. Individual genetic landscapes can contribute to understand Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) burden and can give information on how to fight virus spreading and the associated severe acute respiratory distress syndrome (ARDS). The spread and pathogenicity of the virus have become pandemic on specific geographic areas and ethnicities. Interestingly, SARS-CoV-2 firstly emerged in East Asia and next in Europe, where it has caused higher morbidity and mortality. This is a peculiar feature of SARS-CoV-2, different from past global viral infections (i.e., SARS-1 or MERS); it shares with the previous pandemics strong age- and sex-dependent gaps in the disease outcome. The observation that the severest COVID-19 patients are more likely to have a history of hypertension, diabetes and/or cardiovascular disease and receive Renin-Angiotensin-System (RAS) inhibitor treatment raised the hypothesis that RAS-unbalancing may have a crucial role. Accordingly, we recently published a genetic hypothesis on the role of RAS-pathway genes (ACE1, rs4646994, rs1799752, rs4340, rs13447447; and ACE2, rs2285666, rs1978124, rs714205) and ABO-locus (rs495828, rs8176746) in COVID-19 prognosis, suspecting inherited genetic predispositions to be predictive of COVID-19 severity. In addition, recently, Genome-Wide Association Studies (GWAS) found COVID-19-association signals at locus 3p21.31 (rs11385942) comprising the solute carrier SLC6A20 (Na+ and Cl- coupled transporter family) and at locus 9q34.2 (rs657152) coincident with ABO-blood group (rs8176747, rs41302905, rs8176719), and interestingly, both loci are associated to RAS-pathway. Finally, ACE1 and ACE2 haplotypes seem to provide plausible explanations for why SARS-CoV-2 have affected more heavily some ethnic groups, namely people with European ancestry, than Asians.

Support for the genetic hypothesis of the Black-white achievement gap using polygenic scores and tests for divergent selection

Using the latest methods to detect divergent evolution and polygenic selection, I test the hypothesis that race differences (European-African) in IQ are due to genetic differences.The genetic variants identified by the largest GWAS of education showed clear signatures of differentiation between Africans and Europeans. Across different phenotypes (educational attainment, cognitive performance, math ability), GWAS SNPs had significantly higher average Fst than control SNPs. Contrary to a previous report, the same effect was found also for a GWAS based on a within-family design, that used differences in educational attainment between siblings to partial out shared environmental effects. Polygenic scores for all phenotypes and GWAS types (including within-family design) were higher for Europeans than for Africans.

Late-Life Depression & Alzheimer's Disease: A Proposal For The Bi-directional Threshold Model

Until now, the relationships between late-life depression and Alzheimer’s Disease (AD) and vice versa have only been investigated in terms of one-directional relationships. However, due to the central neuropathological mechanisms underlying both diseases, it is proposed that the interaction is bi-directional. These mechanisms include the stress-response hypothesis, amyloid hypothesis, inflammatory hypothesis, and genetic hypothesis. By reviewing these shared underlying mechanisms, as well as investigating the evidence for both one-directional relationships, a new model is proposed, namely the bi-directional threshold model. Whereas previous research only focused on one-directional interaction, this model is novel in accounting for the bi-directional interaction between AD and late-life depression. Thereby the model contributes to the literature on late-life depression and AD by serving as a starting point for further research. A better understanding of this new model could have major implications in ameliorating the course of both clinical conditions.

THE GENETIC HYPOTHESIS OF THE URANIFERUS MINERALIZATION, EASTERN CHALKIDIKI (NORTHERN GREECE)

This paper presents the genetic hypothesis of αn uranium mineralization observed in Eastern Chalkidiki-Greece. In the area of Stratoni (location Asprochomata) a uranium mineralization is expressing by disseminated primary (orthobrannerite) and secondary (torbernite) U minerals, in the granodioritic body of this area. Genetically it may be the result of uranium redistribution, which occurs in the resisting accecory minerals (e.g monazite) of the granodiorite, by magmatic or meteoric hydrothermal fluids of low temperature. The mineralized granodiorite of Stratoni gives no evidence of a metalliferous pluton, based on the study of hydrothermally altered samples and this ascertainment is a fact that should be confronted with a lot of carefull thought. In the granite of Arnea area, uranium mineralization is in generally absent, excluding some poor one’s, located along the contacts of the granite with small remnants of the hosting rock, expressed in the form of impregnations or veinlets. The possible cause for its formation being the interaction of a secondary low temperature hydrothermal system mainly of meteoric water participation (convective hydrothermal system) with the granite and the hosting wall-rock minerals. The granite of Arnea indicates all the characteristics of a metalliferous granitoid.

A Genetic Multimutation Model of Autism Spectrum Disorder Fits Disparate Twin Concordance Data from the USA and Canada

Whether autism spectrum disorder (ASD) is caused by genetics, environmental factors, or a combination of both is still being debated today. To help resolve this issue, a genetic multimutation model of ASD development was applied to a wide variety of age-of-onset data from the USA and Canada, and the model is shown to fit all the data. Included in this analysis is new, updated data from the Interactive Autism Network (IAN) of the Kennedy Krieger Institute in Baltimore, Maryland. We find that the age-of-onset distribution for males and females is identical, suggesting that ASD may be an autosomal disorder. The ASD monozygote concordance rate in twin data predicted by the genetic multimutation model is shown to be compatible with the observed rates. If ASD is caused entirely by genetics, then the ASD concordance rate of a cohort of monozygote twins should approach 100% as the youngest pair of twins in the cohort passes 10 years of age, a prediction that constitutes a critical test of the genetic hypothesis. Thus, by measuring the ASD concordance rate as a cohort of monozygote twins age, the hypothesis that this disorder is caused entirely by genetic mutations can be tested.