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There are differences in the allele frequency of MTHFR polymorphism between Western and African population. The aim of this study is to determinate the prevalence of MTHFR C677T and A1298C polymorphisms in young and old people living in different areas from Mediterranean to subSaharan areas. The observed vs expected genotype frequencies of 677T were in Hardy Weinberg equilibrium, with the exception of old Sardinian subjects (P=0.02). Calculation of 677T allele frequency in young and old African subjects (8% and 3%, respectively) indicated that the 677T allele was disadvantaged in old Africans (P=0.02). The difference among young and old Sardinians and Sicilians were not significant at the same degree (43% vs 37% P=0.07 and 46% vs 42% P=0.28, respectively). However, the reproducible trend that showed the prevalence of 677T allele in the young subjects of the three studied areas confirms the disadvantage of this polymorphism with the age. There was a significant difference (P=0.005) on the observed vs expected frequency of 1298C homozygosity in African old subjects compared to younger ones, while the observed vs expected genotype frequencies were in equilibrium in young and old Sardinian and Sicilian subjects. The frequencies of 1298C and 1298A alleles were comparable between young and old African, Sardinian and Sicilian subjects. The lower frequency of 677T allele in old African, Sardinian and Sicilian subjects compared to young ones and the absence of TT genotype among old African subjects, should be considered as a consequence of an elevated mortality of 677T carriers. Key words: MTHFR, Sardinia, Sicily, Burkina Faso, young people, old people, nutrition, folic acid, malaria, INTRODUCTION Methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, which is needed for methionine synthase to convert homocysteine (Hcy) to methionine [1]. Its key function in Hcy metabolism [...]

Abstract Background Association studies consist in identifying the genetic variants which are related to a specific disease through the use of statistical multiple hypothesis testing or segregation analysis in pedigrees. This type of studies has been very successful in the case of Mendelian monogenic disorders while it has been less successful in identifying genetic variants related to complex diseases where the insurgence depends on the interactions between different genes and the environment. The current technology allows to genotype more than a million of markers and this number has been rapidly increasing in the last years with the imputation based on templates sets and whole genome sequencing. This type of data introduces a great amount of noise in the statistical analysis and usually requires a great number of samples. Current methods seldom take into account gene-gene and gene-environment interactions which are fundamental especially in complex diseases. In this paper we propose to use a non-parametric additive model to detect the genetic variants related to diseases which accounts for interactions of unknown order. Although this is not new to the current literature, we show that in an isolated population, where the most related subjects share also most of their genetic code, the use of additive models may be improved if the available genealogical tree is taken into account. Specifically, we form a sample of cases and controls with the highest inbreeding by means of the Hungarian method, and estimate the set of genes/environmental variables, associated with the disease, by means of Random Forest. Results We have evidence, from statistical theory, simulations and two applications, that we build a suitable procedure to eliminate stratification between cases and controls and that it also has enough precision in identifying genetic variants responsible for a disease. This procedure has been successfully used for the beta-thalassemia, which is a well known Mendelian disease, and also to the common asthma where we have identified candidate genes that underlie to the susceptibility of the asthma. Some of such candidate genes have been also found related to common asthma in the current literature. Conclusions The data analysis approach, based on selecting the most related cases and controls along with the Random Forest model, is a powerful tool for detecting genetic variants associated to a disease in isolated populations. Moreover, this method provides also a prediction model that has accuracy in estimating the unknown disease status and that can be generally used to build kit tests for a wide class of Mendelian diseases.

Abstract Background A multiplicity of study designs such as gene candidate analysis, genome wide search (GWS) and, recently, whole genome association studies have been employed for the identification of the genetic components of essential hypertension (EH). Several genome-wide linkage studies of EH and blood pressure-related phenotypes demonstrate that there is no single locus with a major effect while several genomic regions likely to contain EH-susceptibility loci were validated by multiple studies. Methods We carried out the clinical assessment of the entire adult population in a Sardinian village (Talana) and we analyzed 16 selected families with 62 hypertensive subjects out of 267 individuals. We carried out a double GWS using a set of 902 uniformly spaced microsatellites and a high-density SNPs map on the same group of families. Results Three loci were identified by both microsatellites and SNP scans and the obtained linkage results showed a remarkable degree of similarity. These loci were identified on chromosome 2q24, 11q23.1–25 and 13q14.11–21.33. Further support to these findings is their broad description present in literature associated to EH or related phenotypes. Bioinformatic investigation of these loci shows several potential EH candidate genes, several of whom already associated to blood pressure regulation pathways. Conclusion Our search for major susceptibility EH genetic factors evidences that EH in the genetic isolate of Talana is due to the contribution of several genes contained in loci identified and replicated by earlier findings in different human populations.

Increased concentrations of serum aspartate transaminase (AST) and alanine transaminase (ALT) are common in COVID‐19 patients. However, their capacity to predict mortality, particularly the AST/ALT ratio, commonly referred to as the De Ritis ratio, is unknown. We investigated the association between the De Ritis ratio on admission and in‐hospital mortality in 105 consecutive patients with coronavirus disease of 2019 (COVID‐19) admitted to three COVID‐19 referral centres in Sardinia, Italy. The De Ritis ratio was significantly lower in survivors than nonsurvivors (median: 1.25; IQR: 0.91‐1.64 vs 1.67; IQR: 1.38‐1.97, P =.002) whilst there were no significant between‐group differences in ALT and AST concentrations. In ROC curve analysis, the AUC value of the De Ritis ratio was 0.701 (95% CI 0.603‐0.787, P =.0006) with sensitivity and specificity of 74% and 70%, respectively. Kaplan‐Meier survival curves showed a significant association between the De Ritis ratio and mortality (logrank test P =.014). By contrast, no associations were observed between the ALT and AST concentrations and mortality (logrank test P =.83 and P =.62, respectively). In multivariate Cox regression analysis, the HR in patients with De Ritis ratios ≥1.63 (upper tertile of this parameter) remained significant after adjusting for age, gender, smoking status, cardiovascular disease, intensity of care, diabetes, respiratory diseases, malignancies and kidney disease (HR: 2.46, 95% CI 1.05‐5.73, P =.037). Therefore, the De Ritis ratio on admission was significantly associated with in‐hospital mortality in COVID‐19 patients. Larger studies are required to confirm the capacity of this parameter to independently predict mortality in this group. [ABSTRACT FROM AUTHOR]

In Burkina Faso the levels of plasma homocysteine (Hcy) are lower and the methionine loading tests suggest a more effective Hcy metabolism. The polymorphisms of methylenetetrahydrofolate reductase (MTHFR) showed a relevant difference in the allele frequencies of T MTHFR-677 in young and in old subjects, while the allele frequency of C MTHFR-1298 was comparable in young and old subjects. The aim of this paper was to study the impact of the MTHFR polymorphisms on plasma fasting Hcy and after methionine loading in Burkina Faso. The young subjects with CC MTHFR-677 genotype had levels of Hcy significantly lower than CT and TT subjects. The level of Hcy in subjects who had AA, AC and CC MTHFR-1298 genotypes were comparable. The levels of Hcy after the methionine loading test were significantly higher in CT and TT MTHFR-677 genotype. These results suggest that the genetic situation in Burkina Faso is different from that of other Western countries and this guarantees the maintenance of lower plasma levels of Hcy in young and old Africans. The elevated levels of plasma Hcy in old subjects compared to young subjects, against the low prevalence of the T allele in elderly subjects, is discussed.