Whole-genome sequencing across multiple samples in a population provides an unprecedented opportunity for comprehensively characterizing the polymorphic variants in the population. Although the 1000 Genomes Project (1KGP) has offered brief insights into the value of population-level sequencing, the low coverage has compromised the ability to confidently detect rare and low-frequency variants. In addition, the composition of populations in the 1KGP is not complete, despite the fact that the study design has been extended to more than 2,500 samples from more than 20 population groups. The Malays are one of the Austronesian groups predominantly present in Southeast Asia and Oceania, and the Singapore Sequencing Malay Project (SSMP) aims to perform deep whole-genome sequencing of 100 healthy Malays. By sequencing at a minimum of 30× coverage, we have illustrated the higher sensitivity at detecting low-frequency and rare variants and the ability to investigate the presence of hotspots of functional mutations. Compared to the low-pass sequencing in the 1KGP, the deeper coverage allows more functional variants to be identified for each person. A comparison of the fidelity of genotype imputation of Malays indicated that a population-specific reference panel, such as the SSMP, outperforms a cosmopolitan panel with larger number of individuals for common SNPs. For lower-frequency (<5%) markers, a larger number of individuals might have to be whole-genome sequenced so that the accuracy currently afforded by the 1KGP can be achieved. The SSMP data are expected to be the benchmark for evaluating the value of deep population-level sequencing versus low-pass sequencing, especially in populations that are poorly represented in population-genetics studies.
Background & Aims We compared the effects of weight loss induced with the glucagon‐like peptide‐1 agonist liraglutide, with that of lifestyle modification, followed by weight maintenance after discontinuing intervention, in obese adults with non‐alcoholic fatty liver disease (NAFLD). Methods Thirty obese (mean age 40.7 ± 9.1 years, BMI 33.2 ± 3.6 kg/m2, 90% male) adults with NAFLD defined as liver fat fraction (LFF) > 5% on magnetic resonance imaging without other causes of hepatic steatosis were randomized to a supervised programme of energy restriction plus moderate‐intensity exercise to induce ≥ 5% weight loss (DE group, n = 15), or liraglutide 3 mg daily (LI group, n = 15) for 26 weeks, followed by 26 weeks with only advice to prevent weight regain. Results Diet and exercise and LI groups had significant (P < 0.01) and similar reductions in weight (−3.5 ± 3.3 vs −3.0 ± 2.2 kg), LFF (−8.1 ± 13.2 vs −7.0 ± 7.1%), serum alanine aminotransferase (−39 ± 35 vs −26 ± 33 U/L) and caspase‐cleaved cytokeratin‐18 (cCK‐18) (−206 ± 252 vs −130 ± 158 U/L) at 26 weeks. At 52 weeks, the LI group significantly (P < 0.05) regained weight (1.8 ± 2.1 kg), LFF (4.0 ± 5.3%) and cCK‐18 (72 ± 126 U/L), whereas these were unchanged in the DE group. Conclusions Liraglutide was effective for decreasing weight, hepatic steatosis and hepatocellular apoptosis in obese adults with NAFLD, but benefits were not sustained after discontinuation, in contrast with lifestyle modification. Continuing the exercise learned in the structured programme contributed to the maintenance of liver fat reduction.
The major histocompatibility complex (MHC) containing the classical human leukocyte antigen (HLA) Class I and Class II genes is among the most polymorphic and diverse regions in the human genome. Despite the clinical importance of identifying the HLA types, very few databases jointly characterize densely genotyped single nucleotide polymorphisms (SNPs) and HLA alleles in the same samples. To date, the HapMap presents the only public resource that provides a SNP reference panel for predicting HLA alleles, constructed with four collections of individuals of north-western European, northern Han Chinese, cosmopolitan Japanese and Yoruba Nigerian ancestry. Owing to complex patterns of linkage disequilibrium in this region, it is unclear whether the HapMap reference panels can be appropriately utilized for other populations. Here, we describe a public resource for the Singapore Genome Variation Project with: (i) dense genotyping across ∼ 9000 SNPs in the MHC; (ii) four-digit HLA typing for eight Class I and Class II loci, in 96 southern Han Chinese, 89 Southeast Asian Malays and 83 Tamil Indians. This resource provides population estimates of the frequencies of HLA alleles at these eight loci in the three population groups, particularly for HLA-DPA1 and HLA-DPB1 that were not assayed in HapMap. Comparing between population-specific reference panels and a cosmopolitan panel created from all four HapMap populations, we demonstrate that more accurate imputation is obtained with population-specific panels than with the cosmopolitan panel, especially for the Malays and Indians but even when imputing between northern and southern Han Chinese. As with SNP imputation, common HLA alleles were imputed with greater accuracy than low-frequency variants.
Summary Background One‐week triple therapy with vonoprazan is endorsed by Japanese guidelines as an alternative to proton pump inhibitor (PPI)‐based triple therapy for first‐line Helicobacter pylori eradication. This contrasts with Western guidelines recommending 2‐week PPI‐based triple therapy. Aim To verify the non‐inferiority of 1‐week vonoprazan‐based triple therapy versus 2‐week PPI‐based triple therapy as first‐line H. pylori eradication in a multiracial Asian cohort. Methods Randomised controlled trial of treatment‐naïve patients with H. pylori infection assigned 1:1 to either 7 days amoxicillin 1 g + clarithromycin 500 mg + vonoprazan 20 mg twice per day or 14 days amoxicillin 1 g + clarithromycin 500 mg + omeprazole OR esomeprazole OR rabeprazole 20 mg twice/day. Subjects were randomly assigned to each PPI 1:1:1 Demographics, H. pylori resistance, CYP 2C19 genotype, eradication success and safety profiles were compared between groups. Results Between June 2019 and June 2021, 252 of 1097 subjects screened were randomised. 244 (age [SD] 51.7 [14.6]) received vonoprazan‐ (n = 119) or PPI‐based (n = 125) triple therapy. Eradication rates by intention‐to‐treat analysis were 87.4% (vonoprazan‐based triple therapy) versus 88.0% (PPI‐based triple therapy. By per protocol analysis: 96.3% (vonoprazan‐based triple therapy) versus 94.0% (PPI‐based triple therapy). Clarithromycin resistance predicted treatment failure on multivariate analysis: RR 11.4; 95% CI [1.4–96.3], p = 0.025. No significant differences in CYP 2C19 genotypes or adverse events occurred between groups. Conclusion One‐week vonoprazan‐based triple therapy achieved comparable efficacy to 2‐week PPI‐based triple therapy and was well tolerated.
South Asia possesses a significant amount of genetic diversity due to considerable intergroup differences in culture and language. There have been numerous reports on the genetic structure of Asian Indians, although these have mostly relied on genotyping microarrays or targeted sequencing of the mitochondria and Y chromosomes. Asian Indians in Singapore are primarily descendants of immigrants from Dravidian-language–speaking states in south India, and 38 individuals from the general population underwent deep whole-genome sequencing with a target coverage of 30X as part of the Singapore Sequencing Indian Project (SSIP). The genetic structure and diversity of these samples were compared against samples from the Singapore Sequencing Malay Project and populations in Phase 1 of the 1,000 Genomes Project (1 KGP). SSIP samples exhibited greater intra-population genetic diversity and possessed higher heterozygous-to-homozygous genotype ratio than other Asian populations. When compared against a panel of well-defined Asian Indians, the genetic makeup of the SSIP samples was closely related to South Indians. However, even though the SSIP samples clustered distinctly from the Europeans in the global population structure analysis with autosomal SNPs, eight samples were assigned to mitochondrial haplogroups that were predominantly present in Europeans and possessed higher European admixture than the remaining samples. An analysis of the relative relatedness between SSIP with two archaic hominins (Denisovan, Neanderthal) identified higher ancient admixture in East Asian populations than in SSIP. The data resource for these samples is publicly available and is expected to serve as a valuable complement to the South Asian samples in Phase 3 of 1 KGP.
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