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Background: Genome-wide association studies of COVID-19 severity have been carried out mostly on European or East Asian populations with small representation of other world regions. Here we explore the worldwide distribution and linkage disequilibrium (LD) patterns of genetic variants previously associated with COVID-19 severity., Methods: We followed up the results of a large Spanish genome-wide meta-analysis on 26 populations from the 1000 Genomes Project by calculating allele frequencies and LD scores of the nine most significant SNPs. We also used the entire set of summary statistics to compute polygenic risk scores (PRSs) and carried out comparisons at the population and continental level., Results: We observed the strongest differences among continental regions for the five top SNPs in chromosome 3. European, American, and South Asian populations showed similar LD patterns. Average PRSs in South Asian and American populations were consistently higher than those observed in Europeans. While PRS distributions were similar among South Asians, the American populations showed striking differences among them., Conclusions: Considering the caveats of PRS transferability across ethnicities, our analysis showed that American populations present the highest genetic risk score, hence potentially higher propensity, for COVID-19 severity. Independent validation is warranted with additional summary statistics and phenotype data.

Background: Genetic variation in glucuronosyltransferases (UGT) is crucial in drug metabolism and risk of some diseases., Aim: To examine genetic variation in UGT in North African populations., Subjects and Methods: Allele frequencies of SNPs UGT1A4 24Thr , UGT1A4 48Val , UGT2B15 85Tyr , UGT2B15 523Thr and UGT2B17 CNV deletion from Morocco, Algeria, Tunisia and Libya were compared to European and Sub-Saharan populations., Results: North Africans are the group with the highest genetic heterogeneity given by internal differences in the occurrence of UGT2B17 deletion, UGT1A4 48Val and UGT1A4 haplotypes. UGT2B15 SNPs differentiate Sub-Saharans from the rest of the populations., Conclusion: North African populations show a high frequency of carriers of UGT2B15 523Thr , a variant linked to an increased risk of prostate cancer. High Atlas Moroccans and Algerians show low frequency of UGT2B17 del , a variant associated with high concentrations of testosterone and oestradiol.

Aim: To describe the diversity of four cytochrome and four sulfotransferase polymorphisms in six north African samples. Scarce data have been compiled for these samples despite the rich genetic background of north African populations., Materials & Methods: CYP3A4*1B, CYP3A4*17, CYP3A4*3, CYP3A5*3, SULT1A1*2, SULT1A2*2, SULT1A2*3 and SULT1E1*2 polymorphisms were explored in 556 individuals from Morocco, Algeria, Tunisia and Libya., Results: Allele frequencies in our samples largely exceeded the variation ranges described for European populations, especially for CYP3A4*1B, SULT1A1*2 and SULT1A2*3., Conclusion: North African populations are heterogeneous, genetically diverse and show a considerable sub-Saharan African contribution for markers associated with increased risk of prostate cancer and with differential drug metabolism.

Aim: The purpose of this study was to determine the allelic and genotypic frequency distribution of the C34T mutation in the muscle isoform of the adenosine monophosphate deaminase 1 (AMPD1) gene and of the missense substitution K153R in the myostatin (GDF8) gene in one Spanish and two North African populations., Method: One sample of 98 individuals was genotyped from the South of Spain (Alpujarra) and two samples from Morocco (77 Berbers and 78 Arabs)., Results: The frequency of the AMPD1 C34T mutation was lower in Berbers (0.071) compared with the Alpujarra cohort (0.153, p = 0.018). The GDF8 K153R substitution showed little variability among the three cohorts., Conclusions: Studies with larger cohorts and other ethnic groups are needed to corroborate that there does not exist any major variability in the genotype distribution of genes associated with muscle phenotypes in the South-Eastern Mediterranean area.

Y-chromosome STR polymorphisms are inherited in a haploid state which makes them a powerful tool for easy tracing of paternal lineage and for use in human population evolutionary studies. North-African Y chromosomal diversity has traditionally been studied in order to find genetic and geographic associations as well as to test how natural and cultural barriers have affected the degree of genetic flow not only within North Africa but also in a wider Mediterranean context. The degree of Berber/Arab genetic differentiation in the Moroccan population has been tested for a complete set of forensic markers as sixteen Y-chromosomal short tandem repeats (STRs) (DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635 and GATA H4.1). The results suggest considerable population heterogeneity in North Africa.

Sixteen Y-chromosomal short tandem repeats (STRs) (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635 and GATA H4.1) were typed in DNA samples from 52 unrelated men and 15 autosomal STRs (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX, vWA) were also studied for a group of 90 individuals (men and women) from the same population (Andalusians from La Alpujarra, South of Spain). The Alpujarrenian population represents an example of an isolated population with remarkable geographical, cultural and historical characteristics. High haplotype diversities were observed for the studied polymorphisms, 0.98 and 1 for YSTRs and autosomal STRs, respectively. Population comparisons for the autosomal STR allele distributions revealed remarkable levels of global homogeneity among samples geographically related.