Genetic Diagnosis of Familial Hypercholesterolemia in Asia

Variant Classification Discordance: Contributing Factors and Predictive Models

An ever-growing catalog of human variants is hosted in the ClinVar database. In this database, submissions on a variant are combined into a multisubmitter record; and in the case of discordance in variant classification between submitters, the record is labeled as conflicting. The current study used ClinVar data to identify characteristics that would make variants more likely to be associated with the conflict class of variants. Furthermore, the Extreme Gradient Boosting algorithm was used to train classifier models to provide prediction of classification discordance for single submission variants in ClinVar database. Population allele frequency, the gene harboring the variant, variant type, consequence on protein, variant deleteriousness score, first submitter identity, and submission count were associated with conflict in variant classification. Using such features, the optimized classifier showed accuracy on the test set of 88% with the weighted average of precision, recall, and f1-score of 0.84, 0.88, and 0.85, respectively. There were pronounced associations between variant classification discordance and allele frequency, gene type, and the identity of the first submitter. The study provides the predicted discordance status for single-submitter variants deposited in ClinVar. This approach can be used to assess whether single-submitter variants are likely to be supported, or in conflict with, future entries; this knowledge may help laboratories with clinical variant assessment.

Prevalence and factors associated with possible cases of familial hypercholesterolemia in Brazilian adults: a cross-sectional study

This study aimed to estimate the prevalence of possible cases of FH and analyze associated factors in the adult Brazilian population. Cross-sectional study with laboratory data from the Brazilian National Health Survey, with 8521 participants. Possible cases of FH were defined according to the Dutch Lipid Clinic Network criteria. The prevalence and 95% confidence intervals (95% CI) of possible cases of FH were estimated according to sociodemographic variables, lifestyle, diabetes, hypertension, altered tests, treatment and self-rated health. Logistic regression was used to analyze the associations. The prevalence of possible cases of FH was 0.96%, higher in women, between 45 and 59 years, white race/skin color and others, less education, people with diabetes, hypertension and total cholesterol ≥ 310 mg/dL. The presence of FH was positively associated with regular self-rated health (OR 1.96; 95% CI 0.99-3.84), poor/very poor (OR 3.02; 95% CI 1.30-7.03) and negatively with black race/skin color (OR 0.10; 95% CI 0.02-0.46) and complete elementary school, incomplete high school (OR 0.47; 95% CI 0.23-0.98) and complete high school and more (OR 0.45; 95% CI 0.21-0.95). FH affects 1:104 Brazilian adults, these findings contribute to understanding the burden of disease in Brazil. Due to the scarcity of studies on FH in low- and middle-income countries, further studies are desirable.

Genetic Spectrum and Cascade Screening of Familial Hypercholesterolemia in Routine Clinical Setting in Hong Kong

Familial hypercholesterolemia (FH) is a prevalent but often underdiagnosed monogenic disorder affecting lipoprotein metabolism, and genetic testing for FH has not been widely conducted in Asia in the past. In this cross-sectional study of 31 probands (19 adults and 12 children) and an addition of 15 individuals (12 adults and 3 children), who underwent genetic testing and cascade screening for FH, respectively, during the period between February 2015 and July 2023, we identified a total of 25 distinct LDLR variants in 71.0% unrelated probands. Among the adult proband cohort, a higher proportion of genetically confirmed cases exhibited a positive family history of premature cardiovascular disease. Treatment intensity required to achieve an approximate 50% reduction in pretreatment low-density lipoprotein cholesterol (LDL-C) exhibited potentially better diagnostic performance compared to pretreatment LDL-C levels, Dutch Lipid Clinic Network Diagnostic Criteria (DLCNC) score, and modified DLCNC score. Adult individuals identified through cascade screening demonstrated less severe phenotypes, and fewer of them met previously proposed local criteria for FH genetic testing compared to the probands, indicating that cascade screening played a crucial role in the early detection of new cases that might otherwise have gone undiagnosed. These findings underscore the significance of genetic testing and cascade screening in the accurate identification and management of FH cases.

The Malaysian HEalth and WellBeing AssessmenT (MyHEBAT) Study Protocol: An Initiation of a National Registry for Extended Cardiovascular Risk Evaluation in the Community

Cardiovascular disease (CVD) has been a burden to many developing countries for decades, including Malaysia. Although various steps have been taken to prevent and manage CVD, it remains the leading cause of morbidity and mortality. The rising prevalence of CVD risk factors such as hypertension, hypercholesterolaemia, diabetes, overweight and obesity is the main driving force behind the CVD epidemic. Therefore, a nationwide health study coined as the Malaysian Health and Wellbeing Assessment (MyHEBAT) was designed. It aimed to investigate the prevalence of CVD and the associated risk factors in the community across Malaysia. The MyHEBAT study recruited participants (18-75 years old) through community health screening programmes from 11 states in Malaysia. The MyHEBAT study was further divided into two sub-studies, namely, the Cardiovascular Risk Epidemiological Study (MyHEBAT-CRES) and the MyHEBAT Familial Hypercholesterolaemia Study (MyHEBAT-FH). These studies assessed the prevalence of CVD risk factors and the prevalence of FH in the community, respectively. The data garnered from the MyHEBAT study will provide information for healthcare providers to devise better prevention and clinical practice guidelines for managing CVD in Malaysia.

Genetic Analysis in a Taiwanese Cohort of 750 Index Patients with Clinically Diagnosed Familial Hypercholesterolemia

AIM

Familial hypercholesterolemia (FH) is underdiagnosed in most countries. The genetic heterogeneity of FH requires an algorithm to efficiently integrate genetic testing into clinical practice. We aimed to report the spectrum of genetic mutations from patients with clinically diagnosed FH in Taiwan.

METHODS

Patients with LDL-C＞190 mg/dL or those with probable or definite FH according to the Taiwan Lipid Guidelines underwent genetic testing. Samples from 750 index patients from the Taiwan FH registry were screened using custom-made mass spectrometry, followed by targeted next generation sequencing (NGS) and/or multiplex ligation-dependent probe amplification (MLPA) if found negative.

RESULTS

The mean age of the patients was 52.4±15.1 years and 40.9% were male. Mutations were detected in 445 patients (59.3%). The distribution of mutations was as follows: LDLR (n=395), APOB (n=58), PCSK9 (n=0), and ABCG5 (n=3). The most common mutations were APOB c.10579 C＞T (p.R3527W) (12.6%), LDLR c.986 G＞A (p.C329Y) (11.5%), and LDLR c.1747 C＞T (p.H583Y) (10.8%). LDLR c.1187-10 G＞A (IVS 8-10) and APOB c.10580 G＞A (p.R3527Q) were detected using targeted NGS in Taiwan for the first time. Four novel mutations were identified, including LDLR c.1060＋2 T＞C (IVS 7＋2), LDLR c.1139 A＞C (p.E380A), LDLR c.1322 T＞C (p.A431T)＋c.1867 A＞G (p.I623V), and ABCG5 c.1337 G＞A (p.R447Q).

CONCLUSION

LDLR and APOB, but not PCSK9, mutations were the major genetic causes of FH. Four novel mutations in LDLR or ABCG5 were identified. This genetic screening method using mass spectrometry, targeted NGS, and MLPA analysis provided an efficient algorithm for genetic testing for clinically diagnosed FH in Taiwan.

A Systematic Review and Meta-Analysis of Therapeutic Efficacy and Safety of Alirocumab and Evolocumab on Familial Hypercholesterolemia

Objectives

The aim of this study was to provide the first study to systematically analyze the efficacy and safety of PCSK9-mAbs in the treatment of familial hypercholesterolemia (FH).

Methods

A computer was used to search the electronic Cochrane Library, PubMed/MEDLINE, and Embase databases for clinical trials using the following search terms: "AMG 145", "evolocumab", "SAR236553/REGN727", "alirocumab", "RG7652", "LY3015014", "RN316/bococizumab", "PCSK9", and "familial hypercholesterolemia" up to November 2020. Study quality was assessed with the Cochrane Collaboration's tool, and publication bias was evaluated by a contour-enhanced funnel plot and the Harbord modification of the Egger test. After obtaining the data, a meta-analysis was performed using R software, version 4.0.3.

Results

A meta-analysis was performed on 7 clinical trials (926 total patients). The results showed that PCSK9-mAbs reduced the LDL-C level by the greatest margin, WMD -49.14%, 95% CI: -55.81 to -42.47%, on FH versus control groups. PCSK9-mAbs also significantly reduced lipoprotein (a) (Lp (a)), total cholesterol (TC), triglycerides (TG), apolipoprotein-B (Apo-B), and non-high-density lipoprotein cholesterol (non-HDL-C) levels and increased HDL-C and apolipoprotein-A1 (Apo-A1) levels of beneficial lipoproteins. Moreover, no significant difference was found between PCSK9-mAbs treatment and placebo in common adverse events, serious events, and laboratory adverse events.

Conclusion

PCSK9-mAbs significantly decreased LDL-C and other lipid levels with satisfactory safety and tolerability in FH treatment.

Actionable secondary findings in the 73 ACMG-recommended genes in 1559 Thai exomes

High-throughput DNA sequencing provides not only primary diagnosis but also makes available other genetic variants with potential health implications. the American College of Medical Genetics and Genomics (ACMG) has recommended a list of medically actionable genes since 2013 and very recently released an updated ACMG SF v3.0 list comprising 73 genes. Here, we analyzed exome data of 1559 unrelated Thai individuals to determine the frequency and spectrum of pathogenic (P) or likely pathogenic (LP) variants in the 73 genes. Based on the ACMG guidelines for the interpretation of sequence variants, 68 different P/LP variants in 26 genes associated with 18 diseases inherited in an autosomal-dominant manner of 186 individuals (11.9%; 186/1559) were identified. Of these, 22 P/LP variants in 15 genes associated with 13 diseases of 85 individuals (5.5%; 85/1559) were also reported as P/LP in the ClinVar archive. The majority harbored variants in genes related to cardiovascular diseases (4.7%; 74/1559), followed by cancer phenotypes (0.5%; 8/1559). None of the individuals in our cohort harbored biallelic variants in genes responsible for diseases inherited in an autosomal recessive manner. The results would serve as a basis for precision medicine practice at individual and population levels.

Familial Hypercholesterolaemia in the Malaysian Community: Prevalence, Under-Detection and Under-Treatment

AIM

Familial hypercholesterolaemia (FH) is the most common autosomal dominant lipid disorder, leading to severe hypercholesterolaemia. Early detection and treatment with lipid-lowering medications may reduce the risk of premature coronary artery disease in FH patients. However, there is scarcity of data on FH prevalence, detection rate, treatment and control with lipid-lowering therapy in the Malaysian community.

METHODS

Community participants (n=5130) were recruited from all states in Malaysia. Blood samples were collected for lipid profiles and glucose analyses. Personal and family medical histories were collected by means of assisted questionnaire. Physical examination for tendon xanthomata and premature corneal arcus were conducted on-site. FH were clinically screened using Dutch Lipid Clinic Network Criteria.

RESULTS

Out of 5130 recruited community participants, 55 patients were clinically categorised as potential (Definite and Probable) FH, making the prevalence FH among the community as 1:100. Based on current total population of Malaysia (32 million), the estimated number of FH patients in Malaysia is 320,000, while the detection rates are estimated as 0.5%. Lipid-lowering medications were prescribed to 54.5% and 30.5% of potential and possible FH patients, respectively, but none of them achieved the therapeutic LDL-c target.

CONCLUSION

Clinically diagnosed FH prevalence in Malaysian population is much higher than most of the populations in the world. At community level, FH patients are clinically under-detected, with majority of them not achieving target LDL-c level for high-risk patients. Therefore, public health measures are warranted for early detection and treatment, to enhance opportunities for premature CAD prevention.

Improvement of Definite Diagnosis of Familial Hypercholesterolemia Using an Expanding Genetic Analysis

Background

The deeper understanding of the complex hereditary basis of familial hypercholesterolemia (FH) has raised the rationale of genetic testing, which has been underutilized in clinical practice.

Objectives

The present study aimed to explore the variant spectrum of FH in an expanding manner and compare its diagnostic performance.

Methods

A total of 169 Chinese individuals (124 index cases and 45 relatives) with clinical definite/probable FH were consecutively enrolled. Next-generation sequencing was performed for genetic analysis of 9 genes associated with hypercholesterolemia (major genes: LDLR, APOB, and PCSK9; minor genes: LDLRAP1, LIPA, STAP1, APOE, ABCG5, and ABCG8) including the evaluations of small-scale variants and large-scale copy number variants (CNVs).

Results

Among the 169 clinical FH patients included, 98 (58.0%) were men. A total of 85 (68.5%) index cases carried FH-associated variants. The proportion of FH caused by small-scale variants in LDLR, APOB, and PCSK9 genes was 62.1% and then increased by 6.5% when other genes and CNVs were further included. Furthermore, the variants in LDLR, APOB, and PCSK9 genes occupied 75% of all FH-associated variants. Of note, there were 8 non-LDLR CNVs detected in the present study.

Conclusions

LDLR, APOB, and PCSK9 genes should be tested in the initial genetic screening, although variants in minor genes also could explain phenotypic FH, suggesting that an expanding genetic testing may be considered to further explain phenotypic FH.

Role of PCSK9 Inhibitors in Patients with Familial Hypercholesterolemia

Patients with familial hypercholesterolemia (FH) are at high or very high risk for cardiovascular disease. Those with heterozygous FH (HeFH) often do not reach low-density lipoprotein cholesterol (LDL-C) targets with statin and ezetimibe therapy, and those with homozygous FH (HoFH) usually require additional lipid-modifying therapies. Drugs that inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) offer a novel approach to reduce LDL-C. The monoclonal antibodies, alirocumab and evolocumab, given by subcutaneous injection every 2 or 4 weeks produce reductions in LDL-C of 50% to 60% in patients with HeFH, allowing many of them to achieve their LDL-C goals. Patients with HoFH show a reduced and more variable LDL-C response, which appears to depend on residual LDL receptor activity, and those with receptor-negative mutations may show no response. Inclisiran is a long-acting small interfering RNA therapeutic agent that inhibits the synthesis of PCSK9. Subcutaneous doses of 300 mg can reduce LDL-C by more than 50% for at least 6 months and the responses in HeFH and HoFH patients are similar to those achieved with monoclonal antibodies. These PCSK9 inhibitors are generally well tolerated and they provide a new opportunity for effective treatment for the majority of patients with FH.

Apolipoprotein C1 (APOC1): A Novel Diagnostic and Prognostic Biomarker for Cervical Cancer

BACKGROUND

Previous reports showed that APOC1 was associated with several cancers but the function of APOC1 in cervical cancer was unknown. This study aimed to investigate the clinical effect and function of APOC1 in cervical cancer.

MATERIALS AND METHODS

In this study, the relative expression of APOC1 in cervical cancer was detected by RT-qPCR. In order to determine the cell proliferation and migration and invading ability and apoptosis more accurately, we used CCK8 assay, Edu assay, wound healing assay, migration and invasion assay, flow cytometry assay, co-immunoprecipitation, proteomics and Western blot by silencing and overexpressing APOC1, respectively. The role of APOC1 on tumor progression was explored in vitro and vivo.

RESULTS

The relative expression of APOC1 in cervical cancer tissues was up-regulated (P<0.05). In cervical cancer cell lines, silencing of APOC1 restrained cell progression and EMT, while over-expression of APOC1 accelerated cell progression and EMT in vivo and vitro (P<0.05).

CONCLUSION

APOC1 acts as an oncogene in cervical cancers and knockdown of APOC1 inhibited cervical cancer cells growth in vitro and in vivo. There is a close relationship between the relative expression of APOC1 and clinical outcome in cervical cancer patients.