👤 Pak Chung Sham

Multispecific therapeutics represent an increasingly important approach for enhancing the efficacy in complex diseases. Here, we report the design and optimization of novel antibody-peptide conjugates that combine glucose-dependent insulinotropic polypeptide receptor (GIPR) antagonism with glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism for the treatment of obesity. A series of hybrid molecules was generated by conjugating synthetic GLP-1 peptides to IgG-based anti-GIPR antibodies, yielding markedly prolonged systemic exposure of the structurally intact GLP-1 peptide. In diet-induced obese mice and obese monkeys, once weekly administration of anti-GIPR-Ab/GLP-1 conjugates produced sustained body weight loss and improvements in metabolic parameters. This optimization effort culminated in the discovery of AMG 133, currently in phase III clinical trials with a profile that may support monthly dosing. Show less

Second-generation antipsychotics (SGAs) are widely used to treat schizophrenia (SCZ), but they often induce metabolic side effects like dyslipidemia and obesity. We conducted genome-wide association studies (GWASs) to identify genetic variants associated with SGA-induced lipid and BMI changes in Chinese SCZ patients. A longitudinal cohort of Chinese SCZ receiving SGAs was followed for up to 18.7 years (mean = 5.7 years, SD = 3.3 years). We analysed the patients' genotypes (N = 669), lipid profiles, and BMI using 19 316 prescription records and 3 917 to 7 596 metabolic measurements per outcome. Linear mixed models were employed to evaluate seven SGAs' random effects on metabolic changes for each patient, followed by GWAS and gene set analyses with Bonferroni and FDR correction. Five SNPs achieved p-value < 5 × 10 Show less

Tetralogy of Fallot (TOF) is the most common cyanotic heart defect in neonates. While there is compelling evidence of genetic contribution to the etiology of TOF, the contribution of noncoding variants to the development of the defect remains unexplored. Potentially damaging noncoding de novo variants (NC DNVs) were detected from 141 Chinese nonsyndromic TOF trios (CHN-TOF) and compared with those detected in the Pediatric Cardiac Genomics Consortium (PCGC). Bioinformatic analyses on noncoding and previously detected coding DNVs were performed to identify developmental pathways affected in TOF. Chinese but not PCGC-TOF patients showed a notably increased burden of putative damaging NC DNVs (n = 249). In Chinese, NC and coding DNVs were predominantly associated with cardiomyocyte differentiation and with chamber/valve/aorta development, respectively, producing a combined enrichment in NOTCH signaling (p = 1.1 × 10 Show less

Although low-density lipoprotein cholesterol (LDL-C) is established as the primary cardiovascular disease (CVD) risk factor, some individuals with LDL-C within desirable limits still develop coronary artery disease (CAD). Lipoprotein(a) (Lp(a)) has emerged as a genetically determined independent risk factor for CVD. This study aims to investigate Lp(a) by determining its association with coronary artery stenosis severity, identifying its ethnic-specific genetic determinants and assessing its relationship with an energy-dense dietary pattern. The PUTRA-CV study is a 3-year, multicentre, case-control observational study involving adult patients who have undergone coronary angiography. The primary outcome is the association between Lp(a) levels and the severity of angiographic CAD (assessed by Gensini or Syntax score). Secondary outcomes include the frequencies of Lp(a)-associated single nucleotide polymorphisms (SNPs) (rs10455872 and rs3798220) and the association between dietary patterns and Lp(a) levels. Lp(a) will be measured using a particle-enhanced immunoturbidimetric method, and SNPs will be genotyped using high-resolution melting. Dietary intake will be assessed using a validated semiquantitative food frequency questionnaire. Data will be analysed using SPSS. Descriptive statistics will be used to summarise population characteristics. Bivariate analyses will use chi-square (χ2), independent t-tests or Mann-Whitney U tests as appropriate. The independent association between Lp(a) and coronary artery stenosis severity will be determined using multivariable logistic regression, adjusting for confounders. Empirically driven dietary patterns will be derived using reduced rank regression, and their association with Lp(a) will be assessed. For genetic analysis, allele frequencies of the Ethical approval has been obtained from the ethics committees of the Ministry of Health Malaysia (NMRR ID-24-00877-2ID-IIR), Universiti Putra Malaysia (JKEUPM-2024-246), Universiti Teknologi MARA (REC/07/2024-OT/FB/2) and Universiti Malaya Medical Centre (MREC ID NO: 2 02 453-13692). The findings will be disseminated via peer-reviewed journals and conferences. Show less

Targeted next generation sequencing of gene panels has become a popular tool for the genetic diagnosis of hypertrophic (HCM) and dilated cardiomyopathy (DCM). However, it is uncertain whether the use of Whole Exome Sequencing (WES) represents a more effective approach for diagnosis of cases with HCM and DCM. In this study, we performed indirect comparisons of the coverage and diagnostic yield of WES on genes and variants related to HCM and DCM versus 4 different commercial gene panels using 40 HCM and DCM patients, assuming perfect coverage in those panels. We identified 6 pathogenic or likely pathogenic among 14 HCM patients (diagnostic yield 43%). 3 pathogenic or likely pathogenic were found among the 26 DCM patients (diagnostic yield 12%). The coverage was similar to that of four existing commercial gene panels due to the clustering of mutation within MYH7, MYBPC3, TPM1, TNT2, and TTN. Moreover, the coverage of WES appeared inadequate for TNNI3 and PLN. We conclude that most of the pathogenic variants for HCM and DCM can be found within a small number of genes which were covered by all the commercial gene panels, and the application of WES did not increase diagnostic yield. Show less

Fibroblast growth factor 21 (FGF21) is increasingly recognized as an important metabolic regulator of glucose homeostasis. Here, we conducted an exome-chip association analysis by genotyping 5,169 Chinese individuals from a community-based cohort and two clinic-based cohorts. A custom Asian exome-chip was used to detect genetic determinants influencing circulating FGF21 levels. Single-variant association analysis interrogating 70,444 single nucleotide polymorphisms identified a novel locus, Show less

Schizophrenia is a heritable, heterogeneous common psychiatric disorder. In this study, we evaluated the hypothesis that de novo variants (DNVs) contribute to the pathogenesis of schizophrenia. We performed exome sequencing in Chinese patients (N = 45) with schizophrenia and their unaffected parents (N = 90). Forty genes were found to contain DNVs. These genes had enriched transcriptional co-expression profile in prenatal frontal cortex (Bonferroni corrected p < 9.1 × 10(-3)), and in prenatal temporal and parietal regions (Bonferroni corrected p < 0.03). Also, four prenatal anatomical subregions (VCF, MFC, OFC and ITC) have shown significant enrichment of connectedness in co-expression networks. Moreover, four genes (LRP1, MACF1, DICER1 and ABCA2) harboring the damaging de novo mutations are strongly prioritized as susceptibility genes by multiple evidences. Our findings in Chinese schizophrenic patients indicate the pathogenic role of DNVs, supporting the hypothesis that schizophrenia is a neurodevelopmental disease. Show less

Recent large-scale genome-wide association studies identified novel genetic variants associated with obesity and body mass index (BMI) in addition to the well-described FTO and MC4R genetic variants. This study aimed to examine 13 previously reported obesity and/or BMI-associated loci for associations with obesity in Chinese. This was a cross-sectional case-control study in 470 obese cases (BMI > or =27.5 kg/m(2)) and 700 normal-weight controls (18.5 < or = BMI < or = 23.0 kg/m(2)). A significant association with obesity could be replicated (one tailed P < 0.05) in seven of the 13 single-nucleotide polymorphisms (SNPs) in the case-control study. These included GNPDA2 rs10938397 (P = 7.3 x 10(-4)); FTO rs8050136 (P = 8 x 10(-4)); MC4R rs17782313 (P = 1.2 x 10(-3)); KCTD15 rs29941 (P = 8 x 10(-3)); SFRS10-ETV5-DGKG rs7647305 (P = 0.023); SEC16B-RASAL2 rs10913469 (P = 0.041); and NEGR1 rs3101336 (P = 0.046). Combined genetic risk scores were calculated, and we observed ORs ranging from 1.17 to 1.23 for each unit increase in the genetic risk scores. Associations with obesity-related quantitative traits were analyzed separately for cases and controls. KCTD15 SNP rs29941 (P = 1 x 10(-3)) was significantly associated with fasting glucose in the control group, whereas only the FTO SNP rs8050136 was associated with BMI (P = 3.5 x 10(-3)) in the obese group. However, in an extension study of 1938 subjects from the population-based Hong Kong Cardiovascular Risk Factors Prevalence Study, rs8050136, rs10938397, and rs17782313 showed significant associations with BMI. We have succeeded in replicating, in a Chinese population, the associations with obesity in seven SNPs reported in recent genome-wide association studies. Further functional and fine-mapping studies to elucidate the roles of these putative obesity-related genes and genetic variants are warranted. Show less