Genetics Research
rs316020
Population Frequencies12
African
A 0.14882G 0.85118AA 0.022843AG/GA 0.251952GG 0.725206pop=38,174
African American
A 0.14869G 0.85131AA 0.022913AG/GA 0.251554GG 0.725534pop=37,010
African Others
A 0.1529G 0.8471AA 0.020619AG/GA 0.264605GG 0.714777pop=1,164
Asian
A 0.0326G 0.9674AA 0.000415AG/GA 0.064355GG 0.935229pop=9,634
East Asian
A 0.0336G 0.9664AA 0.00052AG/GA 0.066094GG 0.933385pop=7,686
European
A 0.101262G 0.898738AA 0.010494AG/GA 0.181536GG 0.80797pop=343,436
Latin American 1
A 0.1272G 0.8728AA 0.017073AG/GA 0.220186GG 0.762742pop=7,966
Latin American 2
A 0.06114G 0.93886AA 0.004018AG/GA 0.114236GG 0.881746pop=18,418
Other
A 0.098G 0.902AA 0.012228AG/GA 0.171535GG 0.816236pop=11,776
Other Asian
A 0.0287G 0.9713AA 0AG/GA 0.057495GG 0.942505pop=1,948
South Asian
A 0.1242G 0.8758AA 0.020062AG/GA 0.208333GG 0.771605pop=1,296
Studies13
Unread Studies13 ▼
1
Kidney disease disproportionately affects populations of African ancestry, yet most genetic studies have focused on Europeans. Here, we present a three-stage genome-wide association study meta-analysis of estimated glomerular filtration rate in ~26,000 individuals across Eastern, Western, and Southern Africa and ~81,000 African-ancestry individuals in the diaspora. Continental African meta-analysis identifies four independent genome-wide significant loci, including two previously unreported loci. Pan-African meta-analysis identifies 19 independent loci, including three previously unreported loci. Fine-mapping reveals four loci with high causality probability, and phenome-wide analyses demonstrate pleiotropic effects on cardiometabolic and immunological traits. Notably, APOL1 high-risk variants strongly associated with kidney disease in African Americans show markedly lower frequency and attenuated effects in continental Africa, indicating potential distinct genetic architectures. Polygenic scores from genetically similar populations significantly outperformed those from distant cohorts. These findings demonstrate the necessity of conducting genomic research across diverse African populations to enable equitable health outcomes.
2
To study serum creatinine (Scr) levels and bone mineral density (BMD), we used Mendelian randomization (MR) to investigate the causal relationship between them. The genetic association data of Scr levels and total body BMD across age groups were retrieved from the genome-wide association studies, and the causal relationship between Scr levels and BMD was analyzed using the inverse-variance weighting method, MR-Egger regression method, weighted median estimation method, simple mode, and weighted mode. The results of the inverse-variance weighted method indicated that the creatinine level might be a protective factor for the 45 to 60 age group (P = .005, odds ratio = 1.176, 95% confidence interval = 1.049-1.318). All error lines in the sensitivity analysis graph of the retention method were on the right side of 0, suggesting that the results were highly stable and that the MR results were stable, and no association was found in other age groups. Scr levels exhibited a causal relationship with BMD. As a standard proxy indicator for skeletal muscle mass, Scr levels are correlated with BMD. Reduced Scr levels may indicate sarcopenia, which adversely affects skeletal health. Consequently, monitoring Scr could enable the early identification of individuals at risk of low BMD.
3
Type 2 diabetes (T2D) is a chronic disorder affecting 462 million worldwide, often managed with metformin as first-line treatment. However, metformin’s response varies among individuals, including up to 30% experiencing serious adverse drug reactions (ADRs) and 20-50% inefficacy. These differences may be due to various factors, including pharmacogenetic (PGx) variants. The PGx variants documented so far could affect both the safety and efficacy of metformin, but due to a lack of replication studies, none reached the clinical evidence-level needed to be used as a predictive marker for treatment response. Therefore, this study aims to evaluate the association between the presence of candidate PGx variants and metformin response in T2D subjects. We conducted an association study involving 108 T2D participants currently or previously treated with metformin. A characterization of their therapeutic response was carried out through questionnaires and pharmacological profile reviews. DNA samples were collected during their single visit to perform genotyping of 24 selected candidate PGx variants. Association analyses between candidate PGx variants and metformin response were performed. Among the subjects included in the analyses (n = 84), 25% were non-responders, and 58% experienced ADRs. At the time of study enrollment, 93.9% of non-responders continued to use metformin. The odds of being a non-responder to metformin are 5.6 times higher for homozygous carriers of the alternative allele of a variant within the PCK1 gene (rs4810083) compared to the other genotypes (95% interval confidence [1.9–16.6]). Two variants in perfect linkage disequilibrium within the SLC22A2 gene (rs316019 and rs316009) were associated with increase odds of having ADRs, where homozygous genotype carriers are 7.3 times more likely to have ADRs presentation (95% interval confidence [1.85–29.01]). This study identified associations between PCK1 and SLC22A2 candidate PGx variants and metformin response in T2D treatment. Additional genetic and functional studies are necessary to elucidate the variants’ impact in metformin’s pharmacological mechanisms.
4
Dolutegravir increases serum creatinine by inhibiting its renal tubular secretion and elimination. We investigated determinants of early changes in serum creatinine in a southern African cohort starting first‐line dolutegravir‐based antiretroviral therapy (ART).
5
Dolutegravir increases serum creatinine by inhibiting renal secretion of creatinine, potentially resulting in inappropriate regimen switches. We investigated determinants of early changes in serum creatinine in a Southern African cohort starting dolutegravir-based antiretroviral therapy.
6
Single nucleotide polymorphisms detected in the solute carrier member family-22 has been shown to result in a variable response in the treatment of type 2 diabetes mellitus with Metformin. This study predicted a three-dimensional protein structure for the SLC22A2 protein sequence using AlphaFold 2 and modelled five haplotypes within SLC22A2 protein structure observed in the Xhosa population of South Africa. The protein models were used to determine the effect(s) of haplotype variations on the transport function of Metformin and 10 other drugs by the SLC22A2 protein. Molecular dynamic simulation studies, molecular docking and interaction analysis of the five SLC22A2 haplotypes were performed in complex with the ligand 5RE in a POPC lipid bilayer to understand the mechanism of drug binding. Weakest binding free energy was found between 5RE and haplotype 1. Molecular docking studies indicated the top binding ligands as well as Metformin to bind inside the transport channel in all haplotypes increasing the probability of Metformin inhibition during co-administration of drugs. Metformin showed reduced binding affinity and number of interactions compared to the top four binding molecules. Molecular dynamic simulation analysis indicated that haplotypes 1, 3 and 4 were less stable than 2 and 5. The findings suggest haplotypes 4 and 5 having stronger preference for large inhibitor molecule binding in the active site and this could result in haplotypes 4 and 5 demonstrating reduced Metformin clearance via the SLC22A2 transporter during co-administration of drugs. The current study is the first to investigate the potential effect(s) of haplotype variation on the protein structure of SLC22A2 to assess its ability to transport Metformin in an indigenous South African population.
7
Chronic kidney disease (CKD) affects ~10% of the global population, with considerable ethnic differences in prevalence and aetiology. We assemble genome-wide association studies of estimated glomerular filtration rate (eGFR), a measure of kidney function that defines CKD, in 312,468 individuals of diverse ancestry. We identify 127 distinct association signals with homogeneous effects on eGFR across ancestries and enrichment in genomic annotations including kidney-specific histone modifications. Fine-mapping reveals 40 high-confidence variants driving eGFR associations and highlights putative causal genes with cell-type specific expression in glomerulus, and in proximal and distal nephron. Mendelian randomisation supports causal effects of eGFR on overall and cause-specific CKD, kidney stone formation, diastolic blood pressure and hypertension. These results define novel molecular mechanisms and putative causal genes for eGFR, offering insight into clinical outcomes and routes to CKD treatment development.
8
Metformin is prescribed as a first-line drug to treat type 2 diabetes. It is excreted directly and primarily through the SLC22A2 gene-encoded OCT2 transporter in the kidney. rs316019 (c.808G>T, p.270A>S) is the most common variant of SLC22A2, which affects its capacity to clear metformin from the body. Metformin increases the plasma lactate level in a concentration-dependent manner by inhibiting mitochondrial respiration and may lead to a condition known as metformin-associated lactic acidosis (MALA). MALA is a potentially life-threatening complication that can occur within the clinical doses of metformin. Therefore, dose adjustments based on the SLC22A2 rs316019 variants may be beneficial to maximize the efficacy and minimize the toxicity of metformin.
9
SLC22A2 facilitates the transport of endogenous and exogenous cationic compounds. Many pharmacologically significant compounds are transported by SLC22A2, including the antidiabetic drug metformin, anticancer agent cisplatin, and antiretroviral lamivudine. Genetic polymorphisms in SLC22A2 can modify the pharmacokinetic profiles of such important medicines and could therefore prove useful as precision medicine biomarkers. Since the frequency of SLC22A2 polymorphisms varies among different ethnic populations, we evaluated these in South African Bantu speakers, a majority group in the South African population, who exhibit unique genetic diversity, and we subsequently functionally characterized promoter polymorphisms. We identified 11 polymorphisms within the promoter and 9 single-nucleotide polymorphisms (SNPs) within the coding region of SLC22A2. While some polymorphisms appeared with minor allele frequencies similar to other African and non-African populations, some differed considerably; this was especially notable for three missense polymorphisms. In addition, we functionally characterized two promoter polymorphisms; rs138765638, a three base-pair deletion that bioinformatics analysis suggested could alter c-Ets-1/2, Elk1, and/or STAT4 binding, and rs59695691, an SNP that could abolish TFII-I binding. Significantly higher luciferase reporter gene expression was found for rs138765638 (increase of 37%; p = 0.001) and significantly lower expression for rs59695691 (decrease of 25%; p = 0.038), in comparison to the wild-type control. These observations highlight the importance of identifying and functionally characterizing genetic variation in genes of pharmacological significance. Finally, our data for SLC22A2 attest to the importance of considering genetic variation in different populations for drug safety, response, and global pharmacogenomics, through, for example, projects such as the Human Heredity and Health in Africa initiative.
10
The SLC22A2 gene is a polyspecific transporter that mediates the electrogenic transport of small organic cations with different molecular structures. Furthermore, single-nucleotide polymorphisms (SNPs) of SLC22A2 are clinically significant because they can alter the transport of substrate drugs and may, thus, influence the efficacy and toxicity thereof. Additionally, further studies have reported that SLC22A2 is responsible for 80% of the total metformin clearance. Therefore, loss-of-function variants of SLC22A2 could affect the pharmacokinetic and pharmacodynamic characteristics of metformin. Although it is widely accepted that African populations harbor a greater amount of genomic diversity compared to other populations, limited information is available regarding genetic polymorphisms in SLC genes among African populations, specifically those related to impaired functional activity of hOCT2. Therefore, the aim of this study was to map known impaired function variants in the SLC22A2 gene.
11
Human organic cation transporter 2 (hOCT2) is thought to play a critical role in the uptake, pharmacological effects and/or adverse effects of many cationic clinical therapeutics and xenobiotics. Moreover, genetic variations in hOCT2 gene, SLC22A2, are increasingly being recognized as a possible mechanism that can explain individual variation in drug response. To screen for variations in this gene, SLC22A2 was directly sequenced in 96 healthy Xhosa individuals. A total of 27 variations, including three novel ones, were identified in SLC22A2: eight in exons, 15 in introns, and four in the 5′-untranslated region. The minor allele frequencies (MAF) of genetic variants observed in the Xhosa population were compared both to other African and other world populations. Seventeen of the variants observed in the SLC22A2 gene of the Xhosa population were specific to/or occurred at a higher frequency in African populations or populations with a recent connection to the African continent.
12
Thirty-three genetic variations including fourteen novel ones were found in the SLC22A2 gene from 116 Japanese individuals. The novel variations were as follows: 596C>T (MPJ6_OC2003), 602C>T (MPJ6_OC2004), IVS5+20A>G (MPJ6_OC2010), IVS5-84_-83insG (MPJ6_OC2013), IVS6+30T>C (MPJ6_OC2014), IVS6+146G>T (MPJ6_OC2016), IVS6+179G>T (MPJ6_OC2017), IVS6-16delT (MPJ6_OC2018), 1920G>A (MPJ6_OC2022), 2153G>A (MPJ6_OC2026), 2157C>T (MPJ6_OC2028), 2306T>C (MPJ6_OC2031), 2342+5T>C (the last nucleotide number of mRNA+the position in the 3'-flanking region; MPJ6_OC2032) and 2342+127T>C (MPJ6_OC2033). Six variations were located in the exons, four of which were in the 3'-untranslated region (3'-UTR) of exon 11; six were in the introns; and two were in the 3'-flanking region. The frequencies were 0.802 for IVS5-84_-83insG, 0.013 for 602C>T, 0.009 for 596C>T, and 0.004 for the other 11 variations. Among them, 596C>T and 602C>T resulted in amino acid substitutions (Thr199Ile and Thr201Met, respectively).
13
The same low-activity OCT1 variant ... are further discussed in chapter 7 of this book. ... In the SLC22A2 gene 8 rare nonsynonymous SNPs and one frequent nonsynonymous SNP were identified (Nies et al., 2010)....
Curated Studies0 ▼
These studies were determined to be useful for this variant — check "Unused Studies" further down if curious what didn't make the cut.
No curated studies yet.
Unused Studies0 ▼
No unused studies.