Frequency of APOE, MTHFR and ACE polymorphisms in the Zambian population

Alzheimer Disease Associated Loci: APOE Single Nucleotide Polymorphisms in Marmara Region

Alzheimer's disease (AD) is a major global health challenge, especially among individuals aged 65 or older. According to population health studies, Turkey has the highest AD prevalence in the Middle East and Europe. To accurately determine the frequencies of common and rare APOE single nucleotide polymorphisms (SNPs) in the Turkish population residing in the Marmara Region, we conducted a retrospective study analyzing APOE variants in 588 individuals referred to the Bursa Uludag University Genetic Diseases Evaluation Center. Molecular genotyping, clinical exome sequencing, bioinformatics analysis, and statistical evaluation were employed to identify APOE polymorphisms and assess their distribution. The study revealed the frequencies of APOE alleles as follows: ε4 at 9.94%, ε2 at 9.18%, and ε3 at 80.68%. The gender-based analysis in our study uncovered a tendency for females to exhibit a higher prevalence of mutant genotypes across various SNPs. The most prevalent haplotype observed was ε3/ε3, while rare APOE SNPs were also identified. These findings align with global observations, underscoring the significance of genetic diversity and gender-specific characteristics in comprehending health disparities and formulating preventive strategies.

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.

The association of MTHFR (rs1801133) with hypertension in an indigenous south African population

Aims: The current study sought to investigate the association between the methylenetetrahydrofolate reductase (MTHFR) variant (rs1801133) and the risk of developing hypertension (HTN) in an indigenous South African population.

Methods: A total of 442 participants (hypertensive, n = 279 and non-hypertensive, n = 163) from the indigenous tribe residing in Mthatha, Eastern Cape (South Africa) were recruited. HTN was defined as a systolic (SBP) and diastolic blood pressure (DBP) of ≥130/80 mmHg following American Heart Association guidelines. The genotyping of MTHFR (rs1801133) was assessed using MassARRAY^® System. Thereafter, the association between rs1801133 in various genetic models and HTN was determined by logistic regression model analysis. Furthermore, the interaction between rs1801133 and selected risk factors on HTN was performed using the open-source multifactor dimensionality reduction (MDR).

Results: The low frequency of the T allele (5%) was also observed when compared with the C allele (95%) in both cases and controls. After adjusting for confounding factors (gender, smoking status, BMI, and blood glucose levels), there were no significant associations were observed between rs1801133 and the risk of HTN in all genetic models: genotypic (OR 0.75, 95% CI 0.29–1.95, p = 0.56), dominant (OR 0.86, 95% CI 0.35–2.16, p = 0.75), co-dominant (OR 1.33, 95% CI 0.51–3.48, p = 0.55) and allelic (OR 0.80, 95% CI 0.49–1.62, p = 0.70) in logistic regression analysis. However, a significant interaction was reported among rs1801133, age, and gender (p < 0.0001) with the risk of HTN.

Conclusion: The present study reports on the lack of association between MTHFR (rs1801133) and the risk of HTN in an indigenous South African tribe. However, an interaction between gender, age, and rs1801133 was observed. Thus, future studies with a large sample size are required to further validate these findings.

Methylenetetrahydrofolate Reductase Polymorphism (rs1801133) and the Risk of Hypertension among African Populations: A Narrative Synthesis of Literature

In this review, we have gathered and analyzed the available genetic evidence on the association between the methylenetetrahydrofolate reductase gene (MTHFR), rs1801133 and the risk of Hypertension (HTN) in African populations, which was further compared to the global data evidence. This review was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and Human Genome Epidemiology Network (HuGENet) guidelines. Literature was retrieved through major search databases, including PubMed, Scopus, Web of Science, and African Journal Online. We identified 64 potential studies, of which 4 studies were from the African continent and 60 studies were reported globally. Among the studies conducted in Africa, only two (n = 2) reported a significant association between the MTHFR (rs1801133) and the risk of developing HTN. Only one (n = 1) study population was purely composed of black Africans, while others were of other ethnicities. Among studies conducted in other continents (n = 60), forty-seven (n = 47) studies reported a positive association between MTHFR (rs1801133) and the risk of developing HTN, whereas the remaining studies (n = 14) did not show a significant association. Available literature suggests an apparent association between rs1801133 and HTN in global regions; however, such information is still scarce in Africa, especially in the black African population.

Genetic Regulatory Networks of Apolipoproteins and Associated Medical Risks

Apolipoproteins (APO proteins) are the lipoprotein family proteins that play key roles in transporting lipoproteins all over the body. There are nearly more than twenty members reported in the APO protein family, among which the A, B, C, E, and L play major roles in contributing genetic risks to several disorders. Among these genetic risks, the single nucleotide polymorphisms (SNPs), involving the variation of single nucleotide base pairs, and their contributing polymorphisms play crucial roles in the apolipoprotein family and its concordant disease heterogeneity that have predominantly recurred through the years. In this review, we have contributed a handful of information on such genetic polymorphisms that include APOE, ApoA1/B ratio, and A1/C3/A4/A5 gene cluster-based population genetic studies carried throughout the world, to elaborately discuss the effects of various genetic polymorphisms in imparting various medical conditions, such as obesity, cardiovascular, stroke, Alzheimer's disease, diabetes, vascular complications, and other associated risks.

What could explain the late emergence of COVID-19 in Africa?

At the end of November 2019, a novel coronavirus responsible for respiratory tract infections emerged in China. Despite drastic containment measures, this virus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spread in Asia and Europe. The pandemic is ongoing with a particular hotspot in southern Europe and America in spring 2020. Many studies predicted an epidemic in Africa similar to that currently seen in Europe and the USA. However, reported data do not confirm these predictions. Several hypotheses that could explain the later emergence and spread of the coronavirus disease 2019 (COVID-19) pandemic in African countries are being discussed, including the lack of health-care infrastructure capable of clinically detecting and confirming COVID-19 cases, the implementation of social distancing and hygiene, international air traffic flows, the climate, the relatively young and rural population, the genetic polymorphism of the angiotensin-converting enzyme 2 receptor, cross-immunity and the use of antimalarial drugs.

Ethnogeographic prevalence and implications of the 677C>T and 1298A>C MTHFR polymorphisms in US primary care populations

Aim: Variants of the MTHFR gene have been associated with a wide range of diseases. Materials & methods: The present study analyzed data from clinical genotyping of MTHFR 677C>T and 1298A>C in 1405 patients in urban primary care settings. Results: Striking differences in ethnogeographic frequencies of MTHFR polymorphisms were observed. African-Americans appear to be protected from MTHFR deficiency. Hispanics and Caucasians may be at elevated risk due to increased frequencies of 677C>T and 1298A>C, respectively. Conclusion: Individuals carrying mutations for both genes were rare and doubly homozygous mutants were absent, suggesting the TTcc is extremely rare in the greater population. The results suggest multilocus MTHFR genotyping may yield deeper insight into the ethnogeographic association between MTHFR variants and disease.

Analysis of genetic polymorphism of methylenetetrahydrofolate reductase in a large ethnic Hakka population in southern China

Methylenetetrahydrofolate reductase (MTHFR) catalyzes conversion of methylene tetrahydrofolate to methylte trahydrofolate. MTHFR C677T polymorphism has been regarded as a risk factor for various vascular diseases. Our study aimed to investigate the distribution frequencies of this polymorphism among Hakka population living in southern China. We retrospectively recruited 5102 unrelated Chinese Hakka subjects. MTHFR C677T polymorphism was tested using the polymerase chain reaction (PCR) and DNA sequencing. A total of 2358 males and 2744 females (aged from 10 years to 101 years) were included in this study. In total, 2835 (55.63%) subjects were homozygous for the C allele (CC), 1939 (38.00%) subjects were heterozygous (CT), and 325 (6.37%) subjects were homozygous for the T allele (TT). The allelic frequency of mutant T was 25.37% with 325 individual homozygous for this defective allele resulting in a frequency of about 6.37% for the TT genotype. According to the study results, the overall frequency of MTHFR C677T genotypes did not differ significantly among the gender and age groups. Our study showed the prevalence of MTHFR C677T polymorphism in a large ethnic Hakka population living in southern China. It would be important implications for the primary prevention of various vascular diseases.

Prevalence of common hereditary risk factors for thrombophilia in Somalia and identification of a novel Gln544Arg mutation in coagulation factor V

Thrombophilia, commonly manifested as venous thromboembolism (VTE), is a worldwide concern but little is known on its genetic epidemiology in many parts of the globe particularly in the developing countries. Here we employed TaqMan genotyping and pyrosequencing to evaluate the prevalence of known common nucleotide polymorphisms associated with thrombophilia in a Somali population in the Puntland region of Somalia. We also employed next generation sequencing (NGS) to investigate other genetic variants in a Somali patient with deep venous thrombosis (DVT). As expected, we found no existence of factor V Leiden (rs6025) and prothrombin G20210A (rs1799963) in the Somali population. The G allele of ABO [261G/delG] polymorphism (rs8176719) was found at a frequency of 29%, similar to that observed in other African populations. We found the lowest so far reported frequency of MTHFR C677T (rs1801133) polymorphism in the Somali population (T allele frequency 1.5%). A novel and deleterious single nucleotide variation in exon 11 of coagulation factor V (c.1631A>G) causing Gln544Arg exchange in factor V was identified in a 29 years old Somali female with DVT. The same patient was heterozygous to VKORC1 Asp36Tyr polymorphism (rs61742245) that predisposes to warfarin resistance. In conclusion, this study shows that common hereditary factors for thromboembolism found in Caucasians are either less frequent or absent in the Somali population-similar to the situation in other Africans. NGS is possibly a better choice to detect genetic risk variants for thrombosis in this ethnic group.

Pharmacogenomics of Rosuvastatin: A Glocal (Global+Local) African Perspective and Expert Review on a Statin Drug

The incidence of cardiovascular diseases (CVDs) in African populations residing in the African continent is on the rise fueled by both a steady increase in CVD risk factors and comorbidities such as human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS), tuberculosis, and parasitic diseases such as bilharzia. Statins are recommended together with lifestyle changes in the treatment of hypercholesterolemia and overall reduction of cardiovascular events. Rosuvastatin in particular is an attractive candidate in the management of CVDs in African populations often plagued with multimorbidities owing to both its potency and low drug-to-drug interaction potential. In this expert review, we describe the pharmacogenetics of rosuvastatin and how it may instrumentally affect the African populations. We describe polymorphisms in the candidate genes, ABCG2, SLCO1B1, CYP2C9, APOE, PCSK9, LDLR, LPA, and HMGCR, and their role in the potency and safety of rosuvastatin therapy. We report on qualitative and quantitative differences in the distribution of genetic variants that affect efficacy and toxicity of rosuvastatin. These differences are observed across world populations (Caucasian, European, and Asian) as well as within African populations. Finally, we advocate for extensive pharmacogenetic studies in African populations that take into account the genetic diversity of intra-African ethnic groups and the genetic differences between African populations and other global populations, with a collaborative and collective aim to provide effective and safe use of rosuvastatin in management of CVD in Africa. Our key thesis presented in this innovation field analysis is that rosuvastatin precision medicine can serve as a veritable Glocal (Global and Local) model to offer pharmacogenetic-guided optimal therapeutics for the public in both developing and developed regions of the world.

Association of APOE gene polymorphism with lipid profile and coronary artery disease in Afro-Caribbeans

OBJECTIVES

Apolipoprotein E gene (APOE) polymorphism is associated with the lipid profile and cardio-vascular disease. However, these relationships vary between ethnic groups. We evaluated, for the first time in an Afro-Caribbean population, the distribution of APOE polymorphisms and their associations with coronary artery disease (CAD), the lipid profile and other cardio-metabolic risk factors.

METHODS

We studied 712 Afro-Caribbean subjects including 220 with documented CAD and 492 healthy subjects. TaqMan assays were performed to genotype rs7412 and rs429358, the two variants that determine the APOE alleles ε2, ε3 and ε4. The association between APOE genotype and the lipid profile was analysed by comparing ε2 carriers, ε3 homozygotes and ε4 carriers.

RESULTS

The frequencies of ε2, ε3 and ε4 in the overall sample were 8%, 70% and 22%, respectively. CAD was not associated with APOE polymorphism. The total cholesterol level was higher in ε4 carriers compared with ε2 carriers: 5.07 vs 4.59 mmol/L (P = 0.016). The LDL-cholesterol level was lower in APOE ε2 carriers compared with ε3 homozygotes and ε4 carriers: 2.65 vs 3.03 and 3.17 mmol/L, respectively (p = 0.002). The total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios were similar in the three allelic groups. APOE polymorphism was not associated with diabetes, hypertension, waist circumference or body mass index.

CONCLUSIONS

Our results indicate that APOE gene polymorphism is associated with the lipid profile but not with CAD in Afro-Caribbean people. This lack of association with CAD may be explained by the low atherogenic profile observed in ε4 carriers, which may warrant further investigation.

Lack of association between MTHFR A1298C variant and Alzheimer's disease: evidence from a systematic review and cumulative meta-analysis

OBJECTIVES

Previous studies have investigated the association between MTHFR A1298C (rs1801131) polymorphism and susceptibility to Alzheimer's disease (AD). Nevertheless, an ultimate conclusion remains obscure. We then executed this meta-analysis to estimate this association more precisely.

METHODS

Related studies were systematically searched on PubMed, Embase, China National Knowledge Infrastructure, Google scholar, and AlzGene databases. The association was evaluated by reviewing the odds ratios (ORs) with corresponding 95% confidence intervals (CIs). Publication bias, sensitivity analysis, and cumulative meta-analysis were performed to help draw a more definite conclusion.

RESULTS

Ten eligible studies were finally enrolled in this meta-analysis. Lack of association between MTHFR A1298C polymorphism and AD risk was observed in five genetic models (allelic: OR = 1.17, 95% CI: 0.88-1.56; homozygous: OR = 1.15, 95% CI: 0.87-1.53; heterozygous: OR = 1.19, 95% CI: 0.76-1.86; dominant: OR = 1.23, 95% CI: 0.81-1.87; recessive: OR = 1.16, 95% CI: 0.89-1.52). The result of cumulative meta-analysis sorted by publication year was also detected a dynamic tendency of no correlation between MTHFR A1298C polymorphism and AD.

CONCLUSION

This meta-analysis reveals that MTHFR A1298C polymorphism may not be associated with AD risk.

Genetic diversity of disease-associated loci in Turkish population

Many consortia and international projects have investigated the human genetic variation of a large number of ethno-geographic groups. However, populations with peculiar genetic features, such as the Turkish population, are still absent in publically available datasets. To explore the genetic predisposition to health-related traits of the Turkish population, we analyzed 34 genes associated with different health-related traits (for example, lipid metabolism, cardio-vascular diseases, hormone metabolism, cellular detoxification, aging and energy metabolism). We observed relevant differences between the Turkish population and populations with non-European ancestries (that is, Africa and East Asia) in some of the investigated genes (that is, AGT, APOE, CYP1B1, GNB3, IL10, IL6, LIPC and PON1). As most complex traits are highly polygenic, we developed polygenic scores associated with different health-related traits to explore the genetic diversity of the Turkish population with respect to other human groups. This approach showed significant differences between the Turkish population and populations with non-European ancestries, as well as between Turkish and Northern European individuals. This last finding is in agreement with the genetic structure of European and Middle East populations, and may also agree with epidemiological evidences about the health disparities of Turkish communities in Northern European countries.

Correlation between ApoE gene polymorphisms and the occurrence of urolithiasis

The aim of the present study was to investigate the correlation between apolipoprotein E (ApoE) gene polymorphisms and the occurrence of urolithiasis and dyslipidemia. A total of 180 Uyghur individuals, including 90 urolithiasis patients and 90 healthy controls, were enrolled in this study. The blood lipid profiles of the patients and controls were investigated and compared, and the composition of the urinary calculi was determined. The polymorphisms of the ApoE alleles were analyzed using polymerase chain reaction-restriction fragment length polymorphism analysis. Three common genotypes of the ApoE gene, E3/3, E3/4 and E4/4, were detected in the urolithiasis patients and control group. In the patient group, 28 patients with the E3/3 genotype (30.1%), 58 patients with the E3/4 genotype (64.4%) and four patients with the E4/4 genotype (4.5%) were identified. By contrast, in the control group, 52 patients with the E3/3 genotype (57.8%), 35 patients with the E3/4 genotype (38.9%) and three patients with the E4/4 genotype (3.3%) were identified. The frequency of the E3/4 genotype was found to be significantly higher in the patient group when compared with the control group (χ²=12.96; P<0.001). In addition, the frequency of the E4 allele was significantly higher in the patient group when compared with the control group (χ²= 6.61; P=0.025). In conclusion, the occurrence of urolithiasis was found to be associated with ApoE gene polymorphisms, and the E4 allele may be a potential susceptibility factor for urolithiasis.

Role of apolipoprotein E in neurodegenerative diseases

Apolipoprotein E (APOE) is a lipid-transport protein abundantly expressed in most neurons in the central nervous system. APOE-dependent alterations of the endocytic pathway can affect different functions. APOE binds to cell-surface receptors to deliver lipids and to the hydrophobic amyloid-β peptide, regulating amyloid-β aggregations and clearances in the brain. Several APOE isoforms with major structural differences were discovered and shown to influence the brain lipid transport, glucose metabolism, neuronal signaling, neuroinflammation, and mitochondrial function. This review will summarize the updated research progress on APOE functions and its role in Alzheimer's disease, Parkinson's disease, cardiovascular diseases, multiple sclerosis, type 2 diabetes mellitus, Type III hyperlipoproteinemia, vascular dementia, and ischemic stroke. Understanding the mutations in APOE, their structural properties, and their isoforms is important to determine its role in various diseases and to advance the development of therapeutic strategies. Targeting APOE may be a potential approach for diagnosis, risk assessment, prevention, and treatment of various neurodegenerative and cardiovascular diseases in humans.