👤 Abrar A Qureshi

Homozygous familial hypercholesterolemia (HoFH) is a rare inherited disorder with an extremely elevated level of low-density lipoprotein (LDL) cholesterol (LDL-C) and accelerated premature coronary artery disease (PCAD). It is primarily caused by a single pathogenic variant of the LDL receptor (LDLR) gene. This report presents 2 rare and unrelated cases of HoFH with compound LDLR mutations. These 2 individuals presented with atypical clinical features and demonstrated variable degrees of hypercholesterolemia. Case 1 is a 36-year-old Malay woman identified during family cascade screening with a pretreated LDL-C of 8.5 mmol/L and a strong family history of PCAD. Case 2 is a 58-year-old Indian woman discovered to have a pretreated LDL-C of 5.2 mmol/L during routine health screening, without a significant family history of hypercholesterolemia or PCAD. Neither patient demonstrated tendon xanthomas or other lipid stigmata. Both patients underwent lipid profiling and targeted next-generation sequencing of FH-related genes (LDLR, APOB, PCSK9, ABCG5, and ABCG8). Two novel LDLR variants were identified in exon 18: c.2548-1₂₅₄₈delGAinsTC (pathogenic) and c.2556₂₅₅₇insTCAGTCTGG (p.Leu853Serfs*12; likely pathogenic) and classified according to American College of Medical Genetics and Genomics guidelines. Case 1 was homozygous for both variants, while Case 2 was homozygous for the splice-site variant and heterozygous for the frameshift variant. Both patients received guideline-directed lipid-lowering therapy and ongoing cardiovascular risk management. Despite biallelic LDLR variants, both patients demonstrated relatively milder hypercholesterolemia and absence of classical HoFH stigmata. The LDLR variants located in exon 18 affecting the cytoplasmic tail domain may be associated with attenuated clinical expression. Recognition of genotype-phenotype variability is crucial for accurate diagnosis, risk stratification, and individualized management of HoFH. Show less

Hypertriglyceridemia (HTG) increases cardiovascular and pancreatitis risk. Antisense oligonucleotide (ASO) therapies like volanesorsen and olezarsen target ApoC-III mRNA to reduce ApoC-III, enhancing lipoprotein lipase activity and lowering triglycerides (TGs). This meta-analysis evaluates the efficacy and safety of these ASOs in severe HTG. A systematic review (PROSPERO: CRD42024577110) was conducted following PRISMA, sourcing studies from PubMed, Scopus, Cochrane CENTRAL, and ClinicalTrials.gov until July 2024. Randomized controlled trials (RCTs) involving severe HTG (≥200 mg/dL) treated with volanesorsen or olezarsen vs. placebo were included. Data were synthesized using a random effects model in RevMan 5.4, and bias was assessed with the Cochrane tool. Of 31 identified articles, 9 RCTs (341 patients treated with ASOs, 209 controls) were included. ASOs significantly reduced TG levels [mean difference (MD): -53.72; 95% confidence interval (CI): -77.04 to -30.40; p<0.00001]. Reductions were also seen in very low-density lipoprotein cholesterol (MD: -55.76; p<0.00001), ApoC-III (MD: -74.78; p<0.00001), and APOB48 (MD: -69.45; p<0.00001). Olezarsen uniquely reduced APOB (MD: -15.60; p<0.00001). Non-high-density lipoprotein cholesterol (HDL-C) decreased (MD: -23.25; p<0.00001), while HDL-C increased (MD: +42.14; p<0.00001). Volanesorsen was linked to higher low-density lipoprotein-cholesterol (MD: +62.74; p=0.004). For safety, local injection reactions, thrombocytopenia, and nausea were more common with volanesorsen. Acute pancreatitis occurred only in the placebo group (relative risk: 0.15; p=0.0004), indicating ASO protection. This meta-analysis confirms that ASOs effectively lower TGs and improve lipid profiles in severe HTG. Show less

Coronary artery calcium (CAC) scoring is widely used to screen for coronary artery disease (CAD) in asymptomatic individuals. However, it detects calcified plaques and may miss non-calcified or soft plaques. This study compared the diagnostic accuracy of CAC scoring with coronary computed tomography angiography (CCTA) for detecting CAD in asymptomatic individuals with risk factors. Eighteen asymptomatic adults with a CAC score of 0 underwent CCTA to evaluate for subclinical CAD. Clinical, biochemical, and lifestyle risk factors were assessed. Diagnostic agreement between CAC and CCTA was analyzed using the Wilcoxon signed rank test. The cohort had a mean age of 51.4 ± 10.6 years, 88.8% were male, and mean body mass index (BMI) was 27.7 ± 3.6 kg/m CCTA detected non-calcified atherosclerosis missed by CAC and demonstrated superior sensitivity for early CAD detection in asymptomatic individuals. Show less

Hypertrophic cardiomyopathy (HCM) affects approximately 600,000 people in the United States. Loss-of-function mutations in Myosin Binding Protein C3, MYBPC3, are the most common genetic cause of HCM, with the majority of mutations resulting in haploinsufficiency. To restore cardiac MYBPC3, we use an adeno-associated virus (AAV9) vector and engineer an optimized expression cassette with a minimal promoter and cis-regulatory elements (TN-201) to enhance packaging efficiency and cardiomyocyte expression. Rather than simply preventing cardiac dysfunction preclinically, we demonstrate in a symptomatic MYBPC3-deficient murine model the ability of AAV gene therapy to reverse cardiac hypertrophy and systolic dysfunction, improve diastolic dysfunction, and prolong survival. Dose-ranging efficacy studies exhibit restoration of wild-type MYBPC3 protein levels and saturation of cardiac improvement at the clinically relevant dose of 3E13 vg/kg, outperforming a previously published construct. These findings suggest that TN-201 may offer therapeutic benefits in MYBPC3-associated cardiomyopathy, pending further validation in clinical settings. Show less

Hypoplastic left heart syndrome (HLHS) with risk of poor outcome has been linked to Whole genome sequencing was performed in 197 probands with HLHS, 43 family members, and 813 controls. Data were filtered for rare, segregating variants in 3 index families comprised of an HLHS proband and relative(s) with cardiomyopathy. Whole genome sequencing data from cases and controls were compared for rare variant burden across 56 cardiomyopathy genes utilizing a weighted burden test approach, accounting for multiple testing using a Bonferroni correction. A pathogenic Whole genome sequencing in multiplex families, proband-parent trios, and case-control cohorts revealed defects in cardiomyopathy-associated genes in patients with HLHS, which may portend impaired functional reserve of the single-ventricle circulation. Show less

In a whole-exome sequencing study of multiplex Alzheimer's disease (AD) families, we investigated three neuronal ceroid lipofuscinosis genes that have been linked to retromer, an intracellular trafficking pathway associated with AD: ceroid lipofuscinosis 3 (CLN3), ceroid lipofuscinosis 5 (CLN5), and cathepsin D (CTSD). We identified a missense variant in CLN5 c.A959G (p.Asn320Ser) that segregated with AD. We find that this variant causes glycosylation defects in the expressed protein, which causes it to be retained in the endoplasmic reticulum with reduced delivery to the endolysosomal compartment, CLN5's normal cellular location. The AD-associated CLN5 variant is shown here to reduce the normal processing of cathepsin D and to decrease levels of full-length amyloid precursor protein (APP), suggestive of a defect in retromer-dependent trafficking. Show less

There has been a spectacular rise in the global prevalence of type 2 diabetes mellitus (T2DM), and cardiovascular disease is the major cause of morbidity and mortality in diabetic patients. A variety of diastolic and systolic dysfunctions have been demonstrated in type 2 diabetic heart. The consumption of sugar-sweetened beverages has been linked to rising rates of obesity, which in turn is a risk factor for development of T2DM. In this study, the effects of a sucrose-enriched diet on the pattern of gene expression, contraction and Ca(2+) transport in the Goto-Kakizaki T2DM rat heart were investigated. Genes encoding cardiac muscle proteins (Myh7, Mybpc3, Myl1, Myl3 and Mylpf), intercellular proteins (Gja4), cell membrane transport (Atp1b1), calcium channels (Cacna1c, Cacna1g and Cacnb1) and potassium channels (Kcnj11) were upregulated and genes encoding potassium channels (Kcnb1) were downregulated in GK compared with control rats. Genes encoding cardiac muscle proteins (Myh6, Mybpc3 and Tnn2), intercellular proteins (Gja1 and Gja4), intracellular Ca(2+) transport (Atp2a1 and Ryr2), cell membrane transport (Atp1a2 and Atp1b1) and potassium channel proteins (Kcnj2 and Kcnj8) were upregulated and genes encoding cardiac muscle proteins (Myh7) were downregulated in control rats fed sucrose compared with control rats. Genes encoding cardiac muscle proteins (Myh7) and potassium channel proteins (Kcnj11) were downregulated in control and GK rats fed sucrose compared with control and GK rats, respectively. The amplitude of shortening was reduced in myocytes from the control-sucrose group compared with control rats and in the GK-sucrose group compared with GK rats. The amplitude of the Ca(2+) transient was increased in myocytes from control-sucrose compared with control rats and decreased in GK-sucrose compared with GK rats. Subtle alterations in the pattern of expression of genes encoding a variety of cardiac muscle proteins are associated with changes in shortening and intracellular Ca(2+) transport in ventricular myocytes from GK T2DM and control rats fed a sucrose-enriched diet. Show less

Previous biological studies showed evidence of a genetic link between obesity and pigmentation in both animal models and humans. Our study investigated the individual and joint associations between obesity-related single nucleotide polymorphisms (SNPs) and both human pigmentation and risk of melanoma. Eight obesity-related SNPs in the FTO, MAP2K5, NEGR1, FLJ35779, ETV5, CADM2, and NUDT3 genes were nominally significantly associated with hair color among 5,876 individuals of European ancestry. The genetic score combining 35 independent obesity-risk loci was significantly associated with darker hair color (beta-coefficient per ten alleles = 0.12, P value = 4 × 10(-5)). However, single SNPs or genetic scores showed non-significant association with tanning ability. We further examined the SNPs at the FTO locus for their associations with pigmentation and risk of melanoma. Among the 783 SNPs in the FTO gene with imputation R (2) quality metric >0.8 using the 1,000 genome data set, ten and three independent SNPs were significantly associated with hair color and tanning ability respectively. Moreover, five independent FTO SNPs showed nominally significant association with risk of melanoma in 1,804 cases and 1,026 controls. But none of them was associated with obesity or in linkage disequilibrium with obesity-related variants. FTO locus may confer variation in human pigmentation and risk of melanoma, which may be independent of its effect on obesity. Show less

A potent, selective glucagon receptor antagonist 9m, N-[(4-{(1S)-1-[3-(3,5-dichlorophenyl)-5-(6-methoxynaphthalen-2-yl)-1H-pyrazol-1-yl]ethyl}phenyl)carbonyl]-β-alanine, was discovered by optimization of a previously identified lead. Compound 9m is a reversible and competitive antagonist with high binding affinity (IC(50) of 6.6 nM) and functional cAMP activity (IC(50) of 15.7 nM). It is selective for glucagon receptor relative to other family B GPCRs, showing IC(50) values of 1020 nM for GIPR, 9200 nM for PAC1, and >10000 nM for GLP-1R, VPAC1, and VPAC2. Compound 9m blunted glucagon-induced glucose elevation in hGCGR mice and rhesus monkeys. It also lowered ambient glucose levels in both acute and chronic mouse models: in hGCGR ob/ob mice it reduced glucose (AUC 0-6 h) by 32% and 39% at 3 and 10 mpk single doses, respectively. In hGCGR mice on a high fat diet, compound 9m at 3, and 10 mpk po in feed lowered blood glucose levels by 89% and 94% at day 10, respectively, relative to the difference between the vehicle control and lean hGCGR mice. On the basis of its favorable biological and DMPK properties, compound 9m (MK-0893) was selected for further preclinical and clinical evaluations. Show less

There has been a spectacular rise in the global prevalence of type 2 diabetes mellitus. Cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. Contractile dysfunction, associated with disturbances in excitation-contraction coupling, has been widely demonstrated in the diabetic heart. The aim of this study was to investigate the pattern of cardiac muscle genes that are involved in the process of excitation-contraction coupling in the hearts of early onset (8-10 weeks of age) type 2 diabetic Goto-Kakizaki (GK) rats. Gene expression was assessed in ventricular muscle with real-time RT-PCR; shortening and intracellular Ca(2+) were measured in ventricular myocytes with video edge detection and fluorescence photometry, respectively. The general characteristics of the GK rats included elevated fasting and non-fasting blood glucose and blood glucose at 120 min following a glucose challenge. Expression of genes encoding cardiac muscle proteins (Myh6/7, Mybpc3, Myl1/3, Actc1, Tnni3, Tnn2, Tpm1/2/4 and Dbi) and intercellular proteins (Gja1/4/5/7, Dsp and Cav1/3) were unaltered in GK ventricle compared with control ventricle. The expression of genes encoding some membrane pumps and exchange proteins was unaltered (Atp1a1/2, Atp1b1 and Slc8a1), whilst others were either upregulated (Atp1a3, relative expression 2.61 ± 0.69 versus 0.84 ± 0.23) or downregulated (Slc9a1, 0.62 ± 0.07 versus 1.08 ± 0.08) in GK ventricle compared with control ventricle. The expression of genes encoding some calcium (Cacna1c/1g, Cacna2d1/2d2 and Cacnb1/b2), sodium (Scn5a) and potassium channels (Kcna3/5, Kcnj3/5/8/11/12, Kchip2, Kcnab1, Kcnb1, Kcnd1/2/3, Kcne1/4, Kcnq1, Kcng2, Kcnh2, Kcnk3 and Kcnn2) were unaltered, whilst others were either upregulated (Cacna1h, 0.95 ± 0.16 versus 0.47 ± 0.09; Scn1b, 1.84 ± 0.16 versus 1.11 ± 0.11; and Hcn2, 1.55 ± 0.15 versus 1.03 ± 0.08) or downregulated (Hcn4, 0.16 ± 0.03 versus 0.37 ± 0.08; Kcna2, 0.35 ± 0.03 versus 0.80 ± 0.11; Kcna4, 0.79 ± 0.25 versus 1.90 ± 0.26; and Kcnj2, 0.52 ± 0.07 versus 0.78 ± 0.08) in GK ventricle compared with control ventricle. The amplitude of ventricular myocyte shortening and the intracellular Ca(2+) transient were unaltered; however, the time-to-peak shortening was prolonged and time-to-half decay of the Ca(2+) transient was shortened in GK myocytes compared with control myocytes. The results of this study demonstrate changes in expression of genes encoding various excitation-contraction coupling proteins that are associated with disturbances in myocyte shortening and intracellular Ca(2+) transport. Show less