Allelic Variants Research Articles

Decoding Allosteric Effects of Missense Variations in Drug Metabolism: Afrocentric CYP3A4 Alleles Explored.

Decoding Allosteric Effects of Missense Variations in Drug Metabolism: Afrocentric CYP3A4 Alleles Explored.

Identification of genes associated with milk productivity of cows of simmental and red steppe breeds of Kazakhstan

The genetic structure of the Simmental and Red Steppe breeds at the CSN3, BLG, and PIT-1 loci is characterized by a high frequency of heterozygotes (at the level of 45–50 %). The proportion of homozygotes varies in breeds. Thus, the frequency of CSN3AA and CSN3BB in simmentals is 27 and 24 %, and in Red Steppe breed – 34.2 and 16.6 %. According to the BLG gene, the frequencies of homozygotes in the two breeds are relatively equally distributed – 12 % (BLGAA) and 37 % (BLGBB). In contrast to the equal ratio of allelic variants of the CSN3 gene, the frequency of the BLGB allele is 1.8 times higher than the alternative allele (p < 0.01). Interbreed differences in the frequency of PIT-1AA and PIT-1BB genotypes (p < 0.05) have been established. The frequency of homozygotes in Simmentals is 23 % (PIT-1AA) and 30 % (PIT-1BB), while in the Red Steppe breed it is 9.2 % and 47.5 %, respectively. The frequency distribution of alleles in simmentals is relatively equal, while PIT-1B prevails in the red steppe (70 % versus 30 %). In Simmental cows, it was found that the homozygous CSN3B genotype has a positive effect (p < 0.05) on increasing milk yield, milk protein and fat in milk compared with other genotypes. There are no statistically significant differences between animals of different genotypes in the CSN3 gene in red steppe cows and the ΒLG gene in both breeds. The degree and direction of the relationship between indicators of milk productivity, hematological and biochemical parameters of blood in animals of the Simmental and Red Steppe breeds, taking into account their genotypic affiliation, which can be used in assessing the functional variability of traits, have been established.

Genomic characterization of plasmids of mcr-1-positive Escherichia coli isolated from cohabiting rats, dairy cattle and pigs

BackgroundAntimicrobial resistance has become a significant global issue impacting humans, animals, and the environment. Currently, the focus of concern has shifted to the environment, which can act as a reservoir and significantly contribute to the spread of resistance genes. This study aimed to elucidate the potential transmission of mcr-1, which confers colistin resistance, among Escherichia coli isolates from pigs, dairy cattle, and co-habiting rodents. In March 2018, 30 fecal samples were collected from three pig farms and one mixed cattle farm, and 31 cecal contents from rats (Rattus norvegicus) captured from the same four animal farms were analyzed.ResultsOut of 26 mcr-1 positive E. coli isolates, 16 came from six rats, 10 from four pigs, and none from dairy cattle. The mcr-1-positive isolates from cohabiting rats and pigs were genetically unrelated, based on different XbaI-PFGE profiles. The plasmid profiles of one isolate per animal from each farm were analyzed by S1-PFGE. E. coli isolates from cohabiting rats and pigs showed plasmid bands of similar sizes (33 or 65 kb). To investigate the horizontal transfer of these plasmids between the animals, two pairs of E. coli isolates from pig farms 1 and 3 were selected for WGS analysis. Three of the isolates (EcoP3-1, EcoC2-1 from pigs, and Eco1266-6 from a rat) belonged to clonal complex 10 (CC10), while the other rat isolate (Eco1284-6) belonged to CC398 (ST398). Eco1266-6 (rat) and EcoC2-1 (pig) from cohabiting animals in pig farm 1 carried IncX4 plasmids with the mcr-1.1 variant. The plasmid sequences were almost identical (99.98% identity), both carrying the mcr-1.1/pap2 segment. pEcoC2-1 had a complete ISVsa5 insertion sequence upstream of the mcr-1 gene. Eco1284-6 (rat) and EcoP3-1 (pig) from pig farm 3 carried IncI2 plasmids with different allelic variants of mcr-1 (mcr-1.5 and mcr-1.1).ConclusionsE. coli isolates from cohabiting rats and pigs were genetically distinct, but one pair of isolates had very similar IncX4 plasmids, suggesting the potential for horizontal spread of plasmids carrying mcr genes. These findings suggest a threat of resistant E. coli spreading between cohabiting animals and into the environment. This underscores the importance of conducting integrated One-Health studies.

Evaluation of the budbreak timing in walnut cultivars and breeding forms among the Kuban germplasm, and validation of the trait-related SSR-markers

Background. Walnut (Juglans regia L.) is the most widespread species within the genus Juglans. Late spring frosts can significantly reduce its yield. Development of cultivars that enter the growing season later helps to avoid the death of young buds. Earlier, during genetic studies, the SSR markers JRHR209732 and CUJRBO12 linked to the QTL of the “bud bursting time” character were identified. The objective of this study was to assess the budbreak timing in domestic cultivars and elite forms from the Krasnodar gene pool, as well as to test and validate the markers JRHR209732 and CUJRB012 linked to the locus controlling late bud bursting in walnut genotypes with relatively small differences in budbreak timing.Materials and methods. The material of the study included 32 elite breeding forms from the local gene pool, 3 domestic cultivars, and 2 cultivars of foreign origin. Phenological assessment of the budbreak time was carried out for three years (2022– 2024). Genotyping of 35 accessions was performed using the SSR markers JRHR209732 and CUJRBO12. The sizes of PCR products of target marker alleles were assessed on a NANOPHOR 05 genetic analyzer.Results. Phenological assessment helped to identify accessions 17-5-5 and ‘Oven’ with the latest start of the growing season in three years of observations. Eight genotypes were classified as late in two seasons – they are also valuable for breeding. In 2023 and 2024, the budbreak was observed to occur earlier than in 2022. The effect of the mean monthly temperature in March played a decisive role in entering the phase when the budbreak started. Comparison of the SSR genotyping data with the results of the phenological assessment made it possible to reliably validate the allelic variants of the JRHR20973 and CUJRBO12 markers, characteristic of the accessions with early and late budbreaks among the walnut gene pool maintained in southern Russia.

The presence of multiple variants of IncF plasmid alleles in a single genome sequence can hinder accurate replicon sequence typing using in silico pMLST tools.

Plasmid sequence type is crucial for describing IncF plasmids due to their capacity to carry important antibiotic and virulence gene cargo and consequently due to their association with disease-causing enterobacterial lineages exhibiting resistance to clinically relevant antibiotics in humans and food-producing animals. As a result, precise reporting of IncF allele variants in IncF plasmids is necessary. Comparison of the FAB formulae generated by the pMLST tool with annotated long-read genome assemblies identified inconsistencies, including examples where multiple IncF allele variants were present on the same plasmid but missing in the FAB formula, or in cases where two IncF plasmids were detected in one bacterial cell, and the pMLST output provided information only about one plasmid. Such inconsistencies may cloud interpretation of IncF plasmid replicon type in specific bacterial lineages or inaccurate assumptions of host strain clonality.

Clinical utility of trio whole exome sequencing in fetuses with ultrasound anomalies

IntroductionUltrasound scanning anomalies in fetuses are a cause for concern and often necessitate further diagnostic procedures. This retrospective study evaluated the utility of trio whole exome sequencing (trio-WES) in the diagnosis of fetuses with ultrasound anomalies.MethodsWe included fetuses diagnosed with fetal ultrasound anomalies referred to the First Affiliated Hospital of Chongqing Medical University between November 2018 and July 2023. Fetal anomalies were classified into structural anomalies, dynamic anomalies, and soft markers. Karyotype analysis, chromosomal microarray analysis (CMA) or copy number variation sequencing (CNV-seq) and trio-WES were performed for the eligible cases. Perinatal outcomes were recorded and evaluated at postnatal follow-up.ResultsA total of 316 fetuses were included for the analysis, including 199 (63.0%) cases with structural abnormalities, 63 (19.9%) cases with dynamic abnormalities, and 54 (17.1%) fetuses with ultrasonic soft markers. The diagnostic yield of karyotyping and CMA/CNV-seq was 4.1% (13/316), and Trio-WES achieved an additional diagnosis rate of 15.8% (50/316). Pathogenic or likely pathogenic alleles (P/LP) variants of 132 genes were identified in 125 (39.6%, 125/316) cases, and variant of uncertain significance (VUS) was detected in 81 samples (25.6%, 81/316). Ten cases (3.2%, 10/316,) were found to have pathogenic karyotype or CNVs in supplementary analysis of WES. Fetuses presenting musculoskeletal anomalies and multiple anomalies demonstrated highest diagnostic rates at 36.4% (8/22) and 36.1% (13/36), respectively. The diagnostic rate of fetuses with short femur was 20% (8/40), significantly higher than other ultrasonic soft markers. The modes of inheritance observed in patients with molecular diagnoses were autosomal dominant (AD) in 66.0% cases (33/50), autosomal recessive (AR) in 26.0% cases (13/50), and X-linked (XL) in 8.0% cases (4/50).ConclusionThe integration of CMA/CNV-seq with trio-WES, alongside prenatal ultrasound scanning, holds the promise of significantly enriching our ability to decipher fetal phenotypes. This tripartite approach stands to revolutionize the diagnostic process, offering a more comprehensive and nuanced understanding of the underlying genetic architecture that underpins prenatal anomalies.

Identification and Expression Analysis of CCCH Zinc Finger Family Genes in Oryza sativa

Background: CCCH zinc finger proteins (OsC3Hs) are a class of transcriptional regulators that play important roles in plant development and stress responses. Although their functional significance has been widely studied in model species, comprehensive genome-wide characterization of CCCH proteins in rice (Oryza sativa) remains limited. Methods: Using Arabidopsis CCCH proteins as references, we identified the CCCH gene family in rice and analyzed the physicochemical properties, subcellular localization, conserved structures, phylogeny, cis-regulatory elements, synteny analysis, spatiotemporal expression patterns, and expression patterns under drought, ABA, and MeJA treatments for the identified CCCH family members. Results: The results showed that the rice CCCH family comprises 73 members, which are unevenly distributed across the 12 chromosomes. Phylogenetic analysis classified them into 11 subfamilies. Subcellular localization indicated that most members are localized in the nucleus. The upstream regions of CCCH promoters contain a large number of cis-regulatory elements related to plant hormones and biotic stress responses. Most genes respond to drought, abscisic acid (ABA), and methyl jasmonate (MeJA) treatments. OsC3H36 was highly expressed under drought, ABA, and MeJA treatments. Haplotype analysis of this gene revealed two major allelic variants (H1 and H2), with H1 predominantly found in japonica rice and associated with increased grain width and 1000-grain weight. Functional validation using a chromosome segment substitution line (CSSL1) confirmed these findings. Conclusions: CCCH genes play important roles in rice growth, development, and stress responses. Additionally, we validated that OsC3H36 is associated with rice grain width and 1000-grain weight.

Review of the Genetic Spectrum of Hereditary Spastic Paraplegias in the Middle East and North Africa Regions.

Hereditary spastic paraplegias (HSPs) are inherited neurodegenerative disorders, and their classification is based on inheritance mode, allelic variants, and clinical presentation. Despite global occurrence, research, especially in the Middle East and North Africa (MENA) regions, is lacking, underscoring the need for further investigation. The objective of this study was to improve the regions' clinical practice and public health, and this study aims to gather data on HSP prevalence, pathogenic variants, and patient characteristics in MENA countries. A systematic literature review encompassing PubMed, MEDLINE, and Google Scholar was conducted. Quality assessment was performed on the included studies. Data extraction and analysis provided insights into HSP's current status in the region. Iran had the highest number of patients with HSP, followed by Tunisia. SPG11 (19.8%), FA2H (8.5%), and ZFYVE26 (7.7%) were the most frequently found genes in the cases. Autosomal recessive HSP with thin corpus callosum was common among the affected patients, with SPG11 identified as the primary cause. Our analysis highlights genetic diversity and regional prevalence variations. Despite limited research in MENA countries, we stress the importance of further investigation to address gaps in understanding and improve patient care and public health initiatives.

Whole Genome Variable Number Tandem Repeat Analysis in Alzheimer Disease.

Investigation into different allelic variants may yield new associative genes to predict late-onset Alzheimer disease (LOAD). Variable number tandem repeats (VNTRs) are important polymorphic components of the genome; however, they have been previously overlooked because of their complex genotyping. New software can now determine differing lengths of VNTRs; however, this has not been tested in a large case-control population. We used VNTRseek to genotype over 200,000 tandem repeats in 9,501 cases and controls from the Alzheimer's Disease Sequencing Project. We first identified limiting factors of this analysis and then examined the association of VNTRs with AD diagnosis in a subset of non-Hispanic White participants. We found that VNTRs were highly associated with areas of the genome with a high number of previously identified variants. From our case-control analysis, we identified 9 VNTRs with a repeat allele length associated with LOAD including VNTRs on DSC3, NR2E3, CCNY, PKP4, GRAP, and MAP6. We were able to show the feasibility of this new type of analysis in large-scale whole-genome sequencing data and identify promising VNTRs that are associated with LOAD.

Effects of five allelic variants of the wheat vernalization gene VRN-B1 on heading date and vernalization requirements.

The online version contains supplementary material available at 10.1007/s11032-025-01565-1.

Breeding D1-Type Hybrid Japonica Rice in Diverse Upland Rainfed Environments.

'Dianheyou615' (DHY615) is an elite Dian (D1)-type hybrid japonica rice variety, renowned for its high yield, exceptional grain quality, and unique adaptability to both irrigated and rainfed conditions in the Yungui Plateau of southwestern China. However, the genetic mechanisms underlying the agronomic performance of the D1-type hybrid japonica rice remain unclear. In this study, a comprehensive analysis of 'DHY615''s agronomic performance, genetic genealogy, and molecular genetic foundation was conducted to dissect its desirable traits for upland rainfed cultivation across diverse ecological environments. The main findings indicate that 'DHY615' possesses 6432 heterozygous SNPs, with 57.48% and 14.43% located in the promoter and coding regions, respectively, potentially affecting key phenotypic traits. High-impact SNPs variants and numerous well-known functional genes were identified, such as OsAAP6, GS3, Sd1, Rf1, BADH2, BPh14, Rymv1, OsFRO1, NRT1.1B, SKC1, OsNCED2, and qUVR-10, which are likely linked to traits including plant architecture, grain yield, grain quality, and resistance to various biotic and abiotic stresses (e.g., disease, cold, drought, salt, high iron, and high UV radiation). Notably, 'Nan615' harbors a greater number of functional allele variants compared to 'H479A', which potentially explaining its superior grain yield and remarkable adaptability. This study offers novel and valuable insights into the molecular genetic foundation of the plateau D1-type hybrid japonica rice, underscoring its potential for sustainable rice production across diverse ecological zones, especially with its unparalleled high-altitude adaptability to rainfed upland planting.

A wheat tandem kinase and NLR pair confers resistance to multiple fungal pathogens.

Tandem kinase proteins underlie the innate immune systems of cereal plants, but how they initiate plant immune responses remains unclear. This report identifies wheat protein wheat tandem NBD 1 (WTN1), a noncanonical nucleotide-binding leucine-rich repeat (NLR) receptor featuring tandem nucleotide binding adaptor shared by APAF-1, plant R proteins, and CED-4 (NB-ARC) domains, required for WTK3-mediated disease resistance. Both WTK3 and its allelic variant Rwt4-known for conferring resistance to wheat powdery mildew and blast, respectively-are capable of recognizing the blast effector PWT4. They activate WTN1 to form calcium-permeable channels, akin to ZAR1 and Sr35. Thus, tandem kinase proteins and their associated NLRs operate as "sensor-executor" pairs against fungal pathogens. Additionally, evolutionary analyses reveal a coevolutionary trajectory of the tandem kinase-NLR module, highlighting their cooperative role in triggering plant immunity.

Natural genetic variation in wild-derived mice controls host survival and transcriptional responses during endotoxic shock.

Innate immune cells sense microbial danger signals, resulting in dynamic transcriptional reprogramming and rapid inflammatory responses. If not properly regulated, such responses can be detrimental to the host, as is seen in septic shock. A better understanding of the genetic regulation of responses during endotoxemia could provide potential therapeutic insights. However, the majority of animal model studies have been performed using classic inbred laboratory strains of mice, capturing limited genetic diversity. Here, we compared classic inbred C57BL/6 (B6) mice with wild-derived and genetically divergent PWD/PhJ (PWD) mice using in vivo and in vitro models of endotoxemia. Compared with B6 mice, PWD mice were markedly resistant to bacterial lipopolysaccharide (LPS)-induced endotoxic shock. Using LPS stimulation of bone marrow derived dendritic cells (BMDC) and RNA sequencing, we demonstrate that B6 and PWD BMDCs exhibit partially overlapping yet highly divergent transcriptional responses, with B6 skewed toward stereotypical proinflammatory pathway activation, and PWD engaging regulatory or developmental pathways. To dissect genetic regulation of inflammatory responses by allelic variants, we used BMDCs from a sub-consomic strain carrying a ∼50 Mb PWD-derived portion of chromosome 11 on the B6 background. This identified a subset of cis-regulated and a large number of trans-regulated genes. Bioinformatic analyses identified candidate trans regulators encoded in the chromosome 11 locus as transcription factors Irf1, Ncor1, and Srebf1. Our results demonstrate that natural genetic variation controls host survival and transcriptional reprogramming during endotoxemia, suggesting possibilities for prediction of sepsis risk and/or personalized therapeutic interventions.

Distribution of β-Casein Variants and Effects on Milk Composition in Podolian Cows Reared in Gargano Promontory (Southern Italy).

Distribution of β-Casein Variants and Effects on Milk Composition in Podolian Cows Reared in Gargano Promontory (Southern Italy).

MPSeqM, a tool combining multiplex PCR and high-throughput sequencing to study the polymorphism of eight Leptosphaeria maculans avirulence genes and its application to field surveys in France

ContextLeptosphaeria maculans is a fungal pathogen causing stem canker of oilseed rape (Brassica napus). The disease is mainly controlled by the deployment of varieties with major resistance genes (Rlm). Rlm genes can rapidly become ineffective following the selection of virulent isolates of the fungus, i.e. with mutations, including deletions, in the corresponding avirulence genes (AvrLm). Reasoned and durable management of Rlm genes relies on the detection and monitoring of virulent isolates in field populations. Based on previous knowledge of AvrLm gene polymorphism, we developed a tool combining multiplex PCR and Illumina sequencing to characterize allelic variants for eight AvrLm genes in field L. maculans populations.ResultsWe tested the method on DNA pools of 71 characterised L. maculans isolates and of leaf spots from 32 L. maculans isolates. After multiplex-PCR and sequencing with MiSeq technology, reads were mapped on an AvrLm sequence database. Data were filtered using thresholds defined from control samples included in each sequencing run. Proportions of each allelic variant per gene, including deletions, perfectly correlated with expected ones. The method was then applied to around 1300 symptoms (42 pools of mainly 32 leaf spots) from nine B. napus fields. The proportions of virulent isolates estimated by sequencing leaf spot pools perfectly correlated with those estimated by pathotyping single isolates. In addition, the proportions of allelic variants determined at the national scale also correlated with those previously determined following individual sequencing of AvrLm genes in a representative collection of isolates. Finally, the method also allowed us to detect still undescribed and rare allelic variants.ConclusionsDespite the diversity of mechanisms generating virulent isolates and the gene-dependent diversity of AvrLm gene polymorphism, the method proved suitable for large-scale and regular monitoring of L. maculans populations, which will facilitate the deployment of effective Rlm genes and the early detection of resistance breakdowns.

Modern views on therapy with antidepressants on the background of their individual pharmacogenetics

Annotation. In conducting pharmacotherapy, it is necessary to consider the genetic polymorphism of cytochromes P450, especially when receiving an inadequate response to treatment. Martial law in Ukraine contributed to an increase in the use of antidepressants. When prescribing antidepressants, the genetic polymorphism of their metabolism should be taken into account. The aim of the review is a generalization of modern international ideas regarding the selection, appointment, effectiveness control, and safety forecast in the pharmacotherapy of depressive states with antidepressants of different groups. An analytical search was conducted in international information sources and PubMed scientific database regarding the peculiarities of the use of antidepressants in various categories of patients. The review presents the results of the study of genetic polymorphism of cytochrome P450 in pregnant women and different age groups, they also differ in different countries, especially when using certain groups of antidepressants, which have differences in metabolism due to the effects of cytochrome P450. During pharmacogenomic testing (PGx), it is desirable to take into account the presence of slow, intermediate, normal, fast, and ultrafast types of metabolizes CYP2D6 and CYRS19. Selective serotonin reuptake inhibitors were used as first-line therapy in studies of pregnant women. Metabolism of paroxetine is carried out mainly by CYR2D6, citalopram, escitalopram, and certralin - CYR2C19 enzymes. It is known that pregnancy can increase the activity of CYR2D6 by 25-200%, and CYR2C19, on the contrary, decreases it by 50%. Assessment of the rate of metabolism of antidepressants against the background of slow or intermediate allelic variants of the cytochrome P450 genotype can increase the risks of toxicity of their use. Clarification of these problems remains a promising direction of future analysis in relevant populations, against the background of various physiological states of the body and differences in the course of depression.

Next-generation diagnostics of bloodstream infections enabled by rapid whole-genome sequencing of bacterial cells purified from blood cultures.

Next-generation diagnostics of bloodstream infections enabled by rapid whole-genome sequencing of bacterial cells purified from blood cultures.

Mining sorghum pangenome enabled identification of new dw3 alleles for breeding stable-dwarfing hybrids.

Allele mining of crop pangenomes can enable the identification of novel variants for trait improvement, increase crop genetic diversity, and purge deleterious mutations around fixed genomic regions. Sorghum, a C4 cereal crop domesticated in the tropics, was selected for reduced plant height and maturity to develop combine-harvestable and photoperiod-insensitive US grain sorghums. To breed semi-dwarf US grain sorghum hybrids, public and private sector programs mostly used the dw3-ref allele, which produces undesirable height revertants (frequency of 0.1-0.3%) due to uneven crossing over at the 882 bp tandem duplication region. Although the dw3-ref allele produces revertants, US sorghum breeding programs continued using this allele in the absence of identified allelic variants that suppress revertants. In this study, we leveraged a sorghum pangenome resource (resequenced sorghum association panel and a global diversity panel of 1661 lines) to identify seven loss-of-function variants in the Dw3 gene using the SnpEff variant calling prediction. We validated the Segaolane dw3 loss-of-function variant, resulting from a 137 bp deletion in the third exon, to suppress revertant production. Segaolane NAM family RILs with the dw3-ref allele produced revertants while no revertants were observed in RILs with the Segaolane dw3 allele. The availability of resequencing data enabled the designing of haplotype-based markers detecting the Segaolane stable dw3 allele for marker-assisted trait introgression into elite sorghum breeding lines. This research mining new stable-dwarfing dw3 alleles demonstrated the application of sorghum pan-genome for trait improvement and developing marker-assisted breeding strategies.

Curious Dichotomies of Apolipoprotein E Function in Alzheimer's Disease and Cancer-One Explanatory Mechanism of Inverse Disease Associations?

An apparent "inverse" relationship exists between two seemingly unconnected conditions, Alzheimer's disease (AD) and cancer, despite sharing similar risk factors, like increased age and obesity. AD is associated with amyloid beta (Aβ) plaques and neurofibrillary tau tangles that cause neural degeneration; cancer, in contrast, is characterized by enhanced cell survival and proliferation. Apolipoprotein E (ApoE) is the main lipoprotein found in the central nervous system and via its high affinity with lipoprotein receptors plays a critical role in cholesterol transport and uptake. ApoE has 3 protein isoforms, ApoE E2, ApoE E3, and ApoE E4, respectively encoded for by 3 allelic variants of APOE (ε2, ε3, and ε4). This review examines the characteristics and function of ApoE described in both AD and cancer to assimilate evidence for its potential contribution to mechanisms that may underly the reported inverse association between the two conditions. Of the genetic risk factors relevant to most cases of AD, the most well-known with the strongest contribution to risk is APOE, specifically the ε4 variant, whereas for cancer risk, APOE has not featured as a significant genetic contributor to risk. However, at the protein level in both conditions, ApoE contributes to disease pathology via affecting lipid physiology and transport. In AD, Aβ-dependent and -independent interactions have been suggested, whereas in cancer, ApoE plays a role in immunoregulation. Understanding the mechanism of action of ApoE in these diametrically opposed diseases may enable differential targeting of therapeutics to provide a beneficial outcome for both.

A feasibility study on implementing pre-emptive pharmacogenomics testing in outpatient clinics in Singapore (IMPT study)

In view of the limited data related to preemptive pharmacogenomics (PGx) testing in the primary care setting, we designed a study to assess the feasibility of implementing preemptive PGx services at outpatient clinics, with the aim to assess the practicality and challenges of implementing preemptive PGx testing within primary care, and its impact on clinical workflows and patient care. This prospective study was conducted between October 2022 and August 2023 at five outpatient clinics located in Singapore. Patients aged 21 to 65 with a reported history or risk of developing any of the target chronic conditions or any patients receiving one of the 29 PGx-associated medications were recruited. Patients’ buccal samples were processed using a multi-gene qPCR-based panel of 21 allele variants of five pharmacogenes. Surveys were administered to study participants and clinicians to assess their perceptions and outcomes related to PGx testing. Among the 222 patients, 95% had at least one clinically actionable variant. Of these patients, 113 reported taking at least one of the 29 studied drugs, with 21.2% of them receiving at least one clinically actionable recommendation based on their PGx results. A total of 150 patients (67.6%) participated in the post-test follow-up survey. Among them, 70% expressed feeling relieved and happy upon receiving their test reports and reported increased confidence in taking their prescribed medication. Furthermore, clinicians identified the necessity for clearer legal regulations regarding PGx testing and insurance coverage to enhance future adoption of PGx testing. Given a high prevalence of clinically actionable variants in almost all tested patients, this study underscores the feasibility and clinical benefits of preemptive PGx testing in primary care clinics in Singapore.Clinical Trial Registration: This study is registered with ClinicalTrials.gov, identifier NCT05504135, with the registration date of August 17, 2022.