👤 Jia Nee Foo

Apolipoprotein B [apoB] and lipoprotein(a) [Lp(a)] concentrations are the two prime lipoprotein indices recommended by some expert consensus to assess and manage cardiovascular risk. However, their distributions, associations, inter-relationships, and clinical relevance remain un-investigated in the majority of Asian populations, particularly among healthcare workers. The distributions and relationships of serum Lp(a), apoB, and other lipid biomarker concentrations in 1,927 Asian consenting healthcare workers across ethnicities, sexes, and body mass index (BMI) were analysed. The percentage of apoB content of Lp(a) relative to apoB particle concentrations (Lp(a)-to-apoB proportion) was calculated. Participants’ mean age was 39.4 years, mostly females (79.7%). Ethnicities were Chinese (57.2%), Malay (16.9%), Indian (9.2%), Filipino (12.8%) and others (3.8%). Distribution of Lp(a) was positively skewed to the right for all ethnicities. The median Lp(a) was 16.4 nmol/L (IQR 7.9, 41.8) and ranged between < 7 to 470 nmol/L. The proportion of participants with Lp(a) ≥ 75 nmol/L was 13.9%, and with Lp(a) ≥ 125 nmol/L was 7.8%. Multivariable linear regression analysis showed that being female, older age, and Indian ethnicity were associated with higher Lp(a) levels, whereas being male, older age, Indian ethnicity, and higher BMI were associated with higher mean apoB levels. In this cohort, 11.4% of individuals had Lp(a)-to-apoB proportion > 5%, whilst 3.3% had Lp(a)-to-apoB proportion of > 10%. Among individuals with Lp(a) ≥ 250 nmol/L, the median Lp(a)-to-apoB proportion was 14.9% (IQR 12.6,19.7). Across Lp(a) deciles, the Lp(a)-to-apoB proportions were inversely correlated with LDL-C, non-HDL-C, remnant cholesterol, and triglyceride concentrations. Abnormal Lp(a) (≥ 75 nmol/L) was found in 13.9% of a predominantly female Asian healthcare cohort. In individuals with Lp(a) ≥ 250 nmol/L, Lp(a) particles contributed to the circulating apoB levels by a median of 15%. These findings support the notion that Lp(a) should be integrated into routine lipid assessment in Asian populations, including healthcare workers. clinicaltrial.gov NCT06304415. The online version contains supplementary material available at 10.1186/s12944-026-02912-7. Show less

Lipolysis of triglyceride-rich lipoproteins by peripheral lipoprotein lipase (LPL) plays an essential role in maintaining systemic cholesterol/lipid homeostasis. Human genetic studies have unequivocally demonstrated that activation of LPL pathway reduces risks for both coronary artery disease (CAD) and type 2 diabetes (T2D). Although sterol regulatory element-binding protein 2 (SREBP2) is well established as the master transcription factor that regulates the hepatic biosynthesis of both cholesterol and fatty acids, whether and how its activity in liver interacts with peripheral LPL pathway remains unknown. Here, it is demonstrated that acute liver-specific depletion of SREBP2 results in divergent effects on the regulation of peripheral LPL activity in mice, depending on the presence or absence of low-density lipoprotein receptors (LDLR). SREBP2 deficiency drastically elevates peripheral LPL activity through downregulation of plasma angiopoietin-related protein 3 (ANGPTL3) levels in LDLR-deficient mice. Moreover, in addition to SREBP2's transcriptional regulation of ANGPTL3, it is found that SREBP2 promotes proteasome-based degradation of ANGPTL3 in the presence of LDLR. Remarkably, acute depletion of hepatic SREBP2 protects against hypercholesterolemia and atherosclerosis, in which atherosclerotic lesions are reduced by 45% compared to control littermates. Taken together, these findings outline a liver-peripheral crosstalk mediated by SREBP2-ANGPTL3-LPL axis and suggest that SREBP2 inhibition can be an effective strategy to tackle homozygous familial hypercholesterolemia (HoFH). Show less

Autism spectrum disorders (ASD) comprise many complex and clinically distinct neurodevelopmental conditions, with increasing evidence linking them to parkinsonism. We searched Medline and Embase from inception to 21 March 2022 and reviewed the bibliographies of relevant articles. Studies were screened and reviewed comprehensively by two independent authors. Of 863 references from our search, we included eight clinical studies, nine genetic studies, and five case reports. Regardless of age group, Parkinson's disease (PD) and parkinsonian syndromes were more frequently observed in patients with ASD, though the evidence for increased rates of parkinsonism is less clear for children and adolescents. Parkinsonian features and hypokinetic behavior were common in Rett syndrome, with prevalence estimates ranging from 40% to 80%. Frequently observed parkinsonian features include bradykinesia, rigidity, hypomimia, and gait freezing. PD gene PARK2 copy number variations appear more frequently in ASD cases than controls. Evidence suggests that RIT2 and CD157/BST1 are implicated in ASD and PD, while the evidence for other PD-related genes (DRD2, GPCR37, the SLC gene family, and SMPD1) is less clear. Rare mutations, such as ATP13A2, CLN3, and WDR45, could result in autistic behavior and concomitant parkinsonism. The prevalence of parkinsonism in ASD is substantially greater than in the general population or matched controls. Various PD-associated gene loci, especially PARK2, could confer susceptibility to ASD as well. Important future directions include conducting prospective cohort studies to understand how parkinsonian symptoms may progress, genetic studies to reveal relevant gene loci, and pathophysiologic studies to identify potential therapeutic targets. Show less

Genome-wide association studies (GWASs) have identified numerous susceptibility loci for Parkinson's disease (PD), but its genetic architecture remains underexplored in populations of non-European ancestry. To identify genetic variants associated with PD in the Chinese population, we performed a GWAS using whole-genome sequencing (WGS) in 1,972 cases and 2,478 controls, and a replication study in a total of 8209 cases and 9454 controls. We identified one new risk variant rs61204179 (P Show less

We determined the relationships between DNA sequence variation and DNA methylation using blood samples from 3,799 Europeans and 3,195 South Asians. We identify 11,165,559 SNP-CpG associations (methylation quantitative trait loci (meQTL), P < 10 Show less

Variable penetrance and late-onset phenotypes are key challenges for classifying causal as well as incidental findings in inherited cardiac conditions. Allele frequencies of variants in ancestry-specific populations, along with clinical variant analysis and interpretation, are critical to determine their true significance. Here, we carefully reviewed and classified variants in genes associated with inherited cardiac conditions based on a population whole-genome sequencing cohort of 4810 Singaporeans representing Southeast Asian ancestries. Eighty-nine (1.85%) individuals carried either pathogenic or likely pathogenic variants across 25 genes. Forty-six (51.7%) had variants in causal genes for familial hyperlipidemia, but there were also recurrent variants in Our findings highlight the incidence of disease-related variants in inherited cardiac conditions and emphasize the value of large-scale sequencing in specific ancestries. Follow-up detailed phenotyping and analysis of pedigrees are crucial because assigning pathogenicity will significantly affect clinical management for individuals and their family members. Show less

Non-alcoholic fatty liver disease (NAFLD) is a metabolic liver disease that is thought to be reversible by changing the diet. To examine the impact of dietary changes on progression and cure of NAFLD, we fed mice a high-fat diet (HFD) or high-fructose diet (HFrD) for 9 weeks, followed by an additional 9 weeks, where mice were given normal chow diet. As predicted, the diet-induced NAFLD elicited changes in glucose tolerance, serum cholesterol, and triglyceride levels in both diet groups. Moreover, the diet-induced NAFLD phenotype was reversed, as measured by the recovery of glucose intolerance and high cholesterol levels when mice were given normal chow diet. However, surprisingly, the elevated serum triglyceride levels persisted. Metagenomic analysis revealed dietary-induced changes of microbiome composition, some of which remained altered even after reversing the diet to normal chow, as illustrated by species of the Odoribacter genus. Genome-wide DNA methylation analysis revealed a "priming effect" through changes in DNA methylation in key liver genes. For example, the lipid-regulating gene Apoa4 remained hypomethylated in both groups even after introduction to normal chow diet. Our results support that dietary change, in part, reverses the NAFLD phenotype. However, some diet-induced effects remain, such as changes in microbiome composition, elevated serum triglyceride levels, and hypomethylation of key liver genes. While the results are correlative in nature, it is tempting to speculate that the dietary-induced changes in microbiome composition may in part contribute to the persistent epigenetic modifications in the liver. Show less

Genome-wide association studies (GWAS) on Parkinson's disease (PD) have mostly been done in Europeans and Japanese. No study has been done in Han Chinese, which make up nearly a fifth of the world population. We conducted the first Han Chinese GWAS analysing a total of 22,729 subjects (5,125 PD cases and 17,604 controls) from Singapore, Hong Kong, Malaysia, Korea, mainland China and Taiwan. We performed imputation, merging and logistic regression analyses of 2,402,394 SNPs passing quality control filters in 779 PD cases, 13,227 controls, adjusted for the first three principal components. 90 SNPs with association P < 10-4 were validated in 9 additional sample collections and the results were combined using fixed-effects inverse-variance meta-analysis. We observed strong associations reaching genome-wide significance at SNCA, LRRK2 and MCCC1, confirming their important roles in both European and Asian PD. We also identified significant (P < 0.05) associations at 5 loci (DLG2, SIPA1L2, STK39, VPS13C and RIT2), and observed the same direction of associations at 9 other loci including BST1 and PARK16. Allelic heterogeneity was observed at LRRK2 while European risk SNPs at 6 other loci including MAPT and GBA-SYT11 were non-polymorphic or very rare in our cohort. Overall, we replicate associations at SNCA, LRRK2, MCCC1 and 14 other European PD loci but did not identify Asian-specific loci with large effects (OR > 1.45) on PD risk. Our results also demonstrate some differences in the genetic contribution to PD between Europeans and Asians. Further pan-ethnic meta-analysis with European GWAS cohorts may unravel new PD loci. Show less

Essential tremor (ET) is characterized by postural and action tremor.(1-3) A genome-wide association study (GWAS) identified a LINGO1 gene variant to be associated with ET.(4) Subsequent GWAS further identified an intronic variant (rs3794087) of the main glial glutamate transporter (SLC1A2) gene to be associated with ET with an odds ratio (OR) of approximately 1.4.(5) We conducted a case-control study to examine the SLC1A2 gene variant in an Asian cohort of ET. In addition, we also investigated the variant in patients with Parkinson disease (PD) because the GWAS LINGO1 variant has been implicated in both ET and PD and etiologic links between the conditions have been suggested.(6.) Show less

Nonalcoholic fatty liver disease is associated with hepatic insulin resistance and type 2 diabetes mellitus. Whether this association has a genetic basis is unknown. In 95 healthy Asian Indian men, a group known to have a high prevalence of nonalcoholic fatty liver disease, we genotyped two single-nucleotide polymorphisms (SNPs) in the gene encoding apolipoprotein C3 (APOC3) that are known to be associated with hypertriglyceridemia (rs2854116 [T-455C] and rs2854117 [C-482T]). Plasma apolipoprotein C3 concentrations, insulin sensitivity, and hepatic triglyceride content were measured. We also measured plasma triglyceride concentrations and retinyl fatty acid ester absorption as well as plasma triglyceride clearance after oral and intravenous fat-tolerance tests. Liver triglyceride content and APOC3 genotypes were also assessed in a group of 163 healthy non-Asian Indian men. Carriers of the APOC3 variant alleles (C-482T, T-455C, or both) had a 30% increase in the fasting plasma apolipoprotein C3 concentration, as compared with the wild-type homozygotes. They also had a 60% increase in the fasting plasma triglyceride concentration, an increase by a factor of approximately two in the plasma triglyceride and retinyl fatty acid ester concentrations after an oral fat-tolerance test, and a 46% reduction in plasma triglyceride clearance. The prevalence of nonalcoholic fatty liver disease was 38% among variant-allele carriers and 0% among wild-type homozygotes (P<0.001). The subjects with nonalcoholic fatty liver disease had marked insulin resistance. A validation study involving non-Asian Indian men confirmed the association between APOC3 variant alleles and nonalcoholic fatty liver disease. The polymorphisms C-482T and T-455C in APOC3 are associated with nonalcoholic fatty liver disease and insulin resistance. Show less