A case report of heterozygous familial hypercholesterolaemia with LDLR gene mutation complicated by premature coronary artery disease detected in primary care.

Background: Familial hypercholesterolaemia (FH) is an autosomal dominant genetic condition predominantly caused by the low-density lipoprotein receptor (LDLR) gene mutation. Case summary: This is the case of a 54-year-old Malay woman with genetically confirmed FH complicated by premature coronary artery disease (PCAD). She was clinically diagnosed in primary care at 52 years old, fulfilling the Simon Broome Criteria (possible FH), Dutch Lipid Clinic Criteria (score of 8: probable FH), and Familial Hypercholesterolaemia Case Ascertainment Tool (relative risk score of 9.51). Subsequently, she was confirmed to have a heterozygous LDLR c.190+4A>T intron 2 pathogenic variant at the age of 53 years. She was known to have hypercholesterolaemia and was treated with statin since the age of 25. However, the lipid-lowering agent was not intensified to achieve the recommended treatment target. The delayed FH diagnosis has caused this patient to have PCAD and percutaneous coronary intervention (PCI) at the age of 29 years and a second PCI at the age of 49 years. She also has a very strong family history of hypercholesterolaemia and PCAD, where seven out of eight of her siblings were affected. Despite this, FH was not diagnosed early, and cascade screening of family members was not conducted, resulting in a missed opportunity to prevent PCAD. Discussion: Familial hypercholesterolaemia can be clinically diagnosed in primary care to identify those who may require genetic testing. Multidisciplinary care focuses on improving identification, cascade screening, and management of FH, which is vital to improving prognosis and ultimately preventing PCAD.

High Prevalence of Familial Hypercholesterolemia Due to the Founder Effect of the LDLR c.2271del Variant in Communities of Oaxaca, Mexico.

INTRODUCTION: In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. METHODS: LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. RESULTS: Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). CONCLUSIONS: The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

Prevalent Variants in the LDLR Gene Impair Responsiveness to Rosuvastatin among Family Members of Patients with Premature Myocardial Infarction.

BACKGROUND: Familial hypercholesterolemia (FH) is an inherited metabolic disorder characterized by high levels of low-density lipoprotein cholesterol (LDL-c) from birth. About 85% of all FH cases are caused by pathogenic variants in the LDLR gene. Individuals with FH have increased cardiovascular risk, including a high risk of premature myocardial infarction (PMI). METHODS: We conducted an opportunistic exome screening to identify variants in the LDLR gene among Vietnamese patients with PMI treated at a general hospital in southern Vietnam. A cascade testing for LDLR variants was conducted in their relatives within three generations, and the effects of the LDLR variant on the response to rosuvastatin treatment were also studied using a comparative before-and-after study design on those who were eligible. RESULTS: A total of 99 participants from the three generations of four PMI patients were recruited, mean age 37.3 ± 18.5 years, 56.6% males. Sanger sequencing revealed two variants in the LDLR gene: variant rs577934998 (c.664T>C), detected in 17 individuals within one family, and variant rs12710260 (c.1060+10G>C), found in 32 individuals (49.5%) in the other three families tested. Individuals harboring the variant c.664T>C had significantly higher baseline LDL-c and total cholesterol levels compared to those with variant c.1060+10G>C (classified as benign) or those without LDLR variants, and among the 47 patients subjected to a 3-month course of rosuvastatin therapy, those with variant c.664T>C had a significantly higher risk of not achieving the LDL-c target after the course of treatment compared to the c.1060+10G>C carriers. CONCLUSIONS: These findings provide evidence supporting the existence of pathogenic LDLR variants in Vietnamese patients with PMI and their relatives and may indicate the need for personalizing lipid-lowering therapies. Further studies are needed to delineate the extent and severity of the problem.

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.

Age, Origin and Functional Study of the Prevalent LDLR Mutation Causing Familial Hypercholesterolaemia in Gran Canaria.

The p.(Tyr400_Phe402del) mutation in the LDL receptor (LDLR) gene is the most frequent cause of familial hypercholesterolaemia (FH) in Gran Canaria. The aim of this study was to determine the age and origin of this prevalent founder mutation and to explore its functional consequences. For this purpose, we obtained the haplotypic information of 14 microsatellite loci surrounding the mutation in one homozygous individual and 11 unrelated heterozygous family trios. Eight different mutation carrier haplotypes were identified, which were estimated to originate from a common ancestral haplotype 387 (110-1572) years ago. This estimation suggests that this mutation happened after the Spanish colonisation of the Canary Islands, which took place during the fifteenth century. Comprehensive functional studies of this mutation showed that the expressed LDL receptor was retained in the endoplasmic reticulum, preventing its migration to the cell surface, thus allowing us to classify this LDLR mutation as a class 2a, defective, pathogenic variant.

Identification and Molecular Characterization of a Novel Large-Scale Variant (Exons 4_18 Loss) in the LDLR Gene as a Cause of Familial Hypercholesterolaemia in an Italian Family.

Next-generation sequencing (NGS) is nowadays commonly used for clinical purposes, and represents an efficient approach for the molecular diagnosis of familial hypercholesterolemia (FH). Although the dominant form of the disease is mostly due to the low-density lipoprotein receptor (LDLR) small-scale pathogenic variants, the copy number variations (CNVs) represent the underlying molecular defects in approximately 10% of FH cases. Here, we reported a novel large deletion in the LDLR gene involving exons 4-18, identified by the bioinformatic analysis of NGS data in an Italian family. A long PCR strategy was employed for the breakpoint region analysis where an insertion of six nucleotides (TTCACT) was found. Two Alu sequences, identified within intron 3 and exon 18, could underlie the identified rearrangement by a nonallelic homologous recombination (NAHR) mechanism. NGS proved to be an effective tool suitable for the identification of CNVs, together with small-scale alterations in the FH-related genes. For this purpose, the use and implementation of this cost-effective, efficient molecular approach meets the clinical need for personalized diagnosis in FH cases.

Genetic Spectrum of Familial Hypercholesterolaemia in the Malaysian Community: Identification of Pathogenic Gene Variants Using Targeted Next-Generation Sequencing.

Familial hypercholesterolaemia (FH) is caused by mutations in lipid metabolism genes, predominantly in low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin-type 9 (PCSK9) and LDL receptor adaptor protein 1 (LDLRAP1). The prevalence of genetically confirmed FH and the detection rate of pathogenic variants (PV) amongst clinically diagnosed patients is not well established. Targeted next-generation sequencing of LDLR, APOB, PCSK9 and LDLRAP1 was performed on 372 clinically diagnosed Malaysian FH subjects. Out of 361 variants identified, 40 of them were PV (18 = LDLR, 15 = APOB, 5 = PCSK9 and 2 = LDLRAP1). The majority of the PV were LDLR and APOB, where the frequency of both PV were almost similar. About 39% of clinically diagnosed FH have PV in PCSK9 alone and two novel variants of PCSK9 were identified in this study, which have not been described in Malaysia and globally. The prevalence of genetically confirmed potential FH in the community was 1:427, with a detection rate of PV at 0.2% (12/5130). About one-fourth of clinically diagnosed FH in the Malaysian community can be genetically confirmed. The detection rate of genetic confirmation is similar between potential and possible FH groups, suggesting a need for genetic confirmation in index cases from both groups. Clinical and genetic confirmation of FH index cases in the community may enhance the early detection of affected family members through family cascade screening.

Familial Hypercholesterolemia Presenting as Cerebral Ischemia and Xanthoma.

Familial hypercholesterolemia (FH) is one of the inherited metabolic diseases, demonstrating the low-density lipoprotein receptor (LDLR) abnormality and serum cholesterol level marked elevation. FH has become an extremely high incident cause of occlusive coronary heart disease. However, even though hemorheological disorder caused by hyperlipidemia is a risk factor of ischemic cerebrovascular disease, cerebral infarction caused by FH has not been given much attention. We present a 41-year-old man with a family history of hypercholesterolemia was admitted to our hospital with dizziness, vertigo, slurred speech, and weakness in his left limbs. Head CT scan showed multiple acute cerebral infarction in the right frontal and parietal lobes. He had arcus corneae and less obvious signs of cutaneous xanthomas in the hands and knees. Molecular analysis of the LDLR gene identified heterozygous and missense mutation in exon 12 of the LDLR gene. The final diagnosis was cerebral infarction caused by FH. It is worth noting that cerebral infarction may also occur in patients with FH. Even if the most patients do not have any sign or history of cerebral ischemia, they need more attention to precise examination of the brain.

Identification of New Copy Number Variation and the Evaluation of a CNV Detection Tool for NGS Panel Data in Polish Familial Hypercholesterolemia Patients.

Familial hypercholesterolemia (FH) is an inherited, autosomal dominant metabolic disorder mostly associated with disease-causing variant in LDLR, APOB or PCSK9. Although the dominant changes are small-scale missense, frameshift and splicing variants, approximately 10% of molecularly defined FH cases are due to copy number variations (CNVs). The first-line strategy is to identify possible pathogenic SNVs (single nucleotide variants) using multiple PCR, Sanger sequencing, or with more comprehensive approaches, such as NGS (next-generation sequencing), WES (whole-exome sequencing) or WGS (whole-genome sequencing). The gold standard for CNV detection in genetic diagnostics are MLPA (multiplex ligation-dependent amplification) or aCGH (array-based comparative genome hybridization). However, faster and simpler analyses are needed. Therefore, it has been proposed that NGS data can be searched to analyze CNV variants. The aim of the study was to identify novel CNV changes in FH patients without detected pathogenic SNVs using targeted sequencing and evaluation of CNV calling tool (DECoN) working on gene panel NGS data; the study also assesses its suitability as a screening step in genetic diagnostics. A group of 136 adult and child patients were recruited for the present study. The inclusion criteria comprised at least "possible FH" according to the Simon Broome diagnostic criteria in children and the DLCN (Dutch Lipid Clinical Network) criteria in adults. NGS analysis revealed potentially pathogenic SNVs in 57 patients. Thirty selected patients without a positive finding from NGS were subjected to MLPA analysis; ten of these revealed possibly pathogenic CNVs. Nine patients were found to harbor exons 4−8 duplication, two harbored exons 6−8 deletion and one demonstrated exon 9−10 deletion in LDLR. To test the DECoN program, the whole study group was referred for bioinformatic analysis. The DECoN program detected duplication of exons 4−8 in the LDLR gene in two patients, whose genetic analysis was stopped after the NGS step. The integration of the two methods proved to be particularly valuable in a five-year-old girl presenting with extreme hypercholesterolemia, with both a pathogenic missense variant (c.1747C>T) and exons 9−10 deletion in LDLR. This is the first report of a heterozygous deletion of exons 9 and 10 co-occurring with SNV. Our results suggest that the NGS-based approach has the potential to identify large-scale variation in the LDLR gene and could be further applied to extend CNV screening in other FH-related genes. Nevertheless, the outcomes from the bioinformatic approach still need to be confirmed by MLPA; hence, the latter remains the reference method for assessing CNV in FH patients.

Identification of New Genetic Determinants in Pediatric Patients with Familial Hypercholesterolemia Using a Custom NGS Panel.

The most common form of inherited lipid disorders is familial hypercholesterolemia (FH). It is characterized primarily by high concentrations of the clinical triad of low-density lipoprotein cholesterol, tendon xanthomas and premature CVD. The well-known genetic background are mutations in LDLR, APOB and PCSK9 gene. Causative mutations can be found in 60−80% of definite FH patients and 20−30% of those with possible FH. Their occurrence could be attributed to the activity of minor candidate genes, whose causal mechanism has not been fully discovered. The aim of the conducted study was to identify disease-causing mutations in FH-related and candidate genes in pediatric patients from Poland using next generation sequencing (NGS). An NGS custom panel was designed to cover 21 causative and candidate genes linked to primary dyslipidemia. Recruitment was performed using Simon Broome diagnostic criteria. Targeted next generation sequencing was performed on a MiniSeq sequencer (Illumina, San Diego, CA, USA) using a 2 × 150 bp paired-end read module. Sequencing data analysis revealed pathogenic and possibly pathogenic variants in 33 out of 57 studied children. The affected genes were LDLR, APOB, ABCG5 and LPL. A novel pathogenic 7bp frameshift deletion c.373_379delCAGTTCG in the exon 4 of the LDLR gene was found. Our findings are the first to identify the c.373_379delCAGTTCG mutation in the LDLR gene. Furthermore, the double heterozygous carrier of frameshift insertion c.2416dupG in the LDLR gene and missense variant c.10708C>T in the APOB gene was identified. The c.2416dupG variant was defined as pathogenic, as confirmed by its cosegregation with hypercholesterolemia in the proband's family. Although the APOB c.10708C>T variant was previously detected in hypercholesterolemic patients, our data seem to demonstrate no clinical impact. Two missense variants in the LPL gene associated with elevated triglyceride plasma level (c.106G>A and c.953A>G) were also identified. The custom NGS panel proved to be an effective research tool for identifying new causative aberrations in a genetically heterogeneous disease as familial hypercholesterolemia (FH). Our findings expand the spectrum of variants associated with the FH loci and will be of value in genetic counseling among patients with the disease.

A case of homozygous familial hypercholesterolemia with an atypical phenotype and delayed clinical symptoms.

We describe the casuistry of a homozygous familial hypercholesterolemia female patient with a biallelic missense variant (NM_000527.4:c.1775G>A, p.Gly592Glu) in the LDLR gene, severe hypertriglyceridemia and late manifestation of coronary heart disease not earlier than at the age of 45 years. An atypical phenotype led to a delayed diagnosis.

A Comprehensive Analysis of Genomics and Metagenomics in a Heterozygote Familial Hypercholesterolemia Family.

Familial hypercholesterolemia (FH) is an inherited rare disease leading to markedly elevated low-density lipoprotein cholesterol (LDL-C) levels and increased risk for cardiovascular event. Gut microbiota has been implicated as a pivotal contributing factor in hyperlipidemia, however, its role in FH remains elusive. We performed whole-exome and metagenomics sequencing on a family with 22 members in which myocardial infarctions occurred at a young age with unclear etiology. We confirmed the missense mutation of LDLR c.1723C>T accounted for the abnormal cholesterol metabolism in the family through co-segregation analysis. In addition, Prevotella dentalis was found elevated and strongly associated with LDL-C level in FH family members with mutation of LDLR c.1723C>T compared to unaffected members with hyperlipidemia. Overall, our work suggests that whole-exome sequencing can facilitate identification of disease-causing variants and enable preventive treatment of FH. Our metagenomics analysis provides early insights into potential contributions of host-microbe interactions in genetic and common hypercholesterolemia.

Patients With LDLR and PCSK9 Gene Variants Experienced Higher Incidence of Cardiovascular Outcomes in Heterozygous Familial Hypercholesterolemia.

Background Patients with familial hypercholesterolemia who harbored both low-density lipoprotein receptor (LDLR) and PCSK9 (proprotein convertase subtilisin/kexin type 9) gene variants exhibit severe phenotype associated with substantially high levels of low-density lipoprotein cholesterol. In this study, we investigated the cardiovascular outcomes in patients with both LDLR and PCSK9 gene variants. Methods and Results A total of 232 unrelated patients with LDLR and/or PCSK9 gene variants were stratified as follows: patients with LDLR and PCSK9 (LDLR/PCSK9) gene variants, patients with LDLR gene variant, and patients with PCSK9 gene variant. Clinical demographics and the occurrence of primary outcome (nonfatal myocardial infarction) were compared. The observation period of primary outcome started at the time of birth and ended at the time of the first cardiac event or the last visit. Patients with LDLR/PCSK9 gene variants were identified in 6% of study patients. They had higher levels of low-density lipoprotein cholesterol (P=0.04) than those with LDLR gene variants. On multivariate Cox regression model, they experienced a higher incidence of nonfatal myocardial infarction (hazard ratio, 4.62; 95% CI, 1.66-11.0; P=0.003 versus patients with LDLR gene variant). Of note, risk for nonfatal myocardial infarction was greatest in male patients with LDLR/PCSK9 gene variants compared with those with LDLR gene variant (86% versus 24%; P<0.001). Conclusions Patients with LDLR/PCSK9 gene variants were high-risk genotype associated with atherogenic lipid profiles and worse cardiovascular outcomes. These findings underscore the importance of genetic testing to identify patients with LDLR/PCSK9 gene variants, who require more stringent antiatherosclerotic management.

Characterisation of LDL receptor gene mutations in a North Indian cohort of children with homozygous familial hypercholesterolaemia.

INTRODUCTION: Homozygous familial hypercholesterolaemia (HoFH) carries a grave prognosis but is often underdiagnosed and undertreated. Confirmation of molecular diagnosis helps in planning effective management and determining prognosis accurately. Aim of the study: To determine the spectrum of mutations in the LDLR gene in a cohort of children with a clinical diagnosis of HoFH. MATERIAL AND METHODS: Genomic DNA was extracted from peripheral blood samples of 8 patients, who were children of either sex, aged under 16 years, and diagnosed clinically with HoFH using the Simon Broome criteria. The potential variants in the LDLR gene were analysed by Sanger sequencing. RESULTS: Fifty variations were found in the 8 patients; 39 (78%) were single nucleotide variations while 8 (16%) and 3 (6%) were deletions and insertions, respectively. The pathogenic variants in the LDLR gene were detected in four patients; three showed duplication in exon 17 (c.2416dupG) creating an amino acid change at position 806 (p.Val806GlyfsTer11) while one had a missense variant in the exon 9 at position c.1285G>A resulting in a change in amino acid at position 429 (p.Val429Met). The variants were found in heterozygous state in the parents or siblings of probands who showed pathogenic variants. CONCLUSIONS: The frequency of disease-causing variants in the LDLR gene in our patients with HoFH was 50%. Further studies to characterise mutations in genes for apolipoprotein B, proprotein convertase subtilisin/kexin type 9, or LDL adaptor protein are suggested in all children with a clinical diagnosis of HoFH.

A successful pregnancy outcome of homozygous familial hypercholesterolaemia patient on statin therapy

@#Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disorder of lipoprotein metabolism mainly due to mutation of the low-density lipoprotein (LDL)-receptor gene (LDLR). It is a life-threatening disease that causes accelerated, multi-vessel atherosclerosis presented in early childhood. Pregnancy in HoFH may pose early coronary morbidity and mortality to both the foetus and mother. The combination of HoFH and pregnancy can be a fatal condition. While statins are very effective in lowering low-density lipoprotein cholesterol (LDL-C) levels, they are generally contraindicated during pregnancy, thus their use during pregnancy is uncommon. On the other hand, lipid apheresis (LA) has turned into an effective treatment to control cholesterol level amid pregnancy. However, the procedure is not widely available in our region. To date, there are scarcely documented case reports of HoFH in pregnancy in which the majority of them underwent LA to keep LDL-C at a low level. We report a rare case of successful pregnancy outcome of HoFH patient treated with lipid-lowering drugs including statin without LA therapy. Apart from that, we also discussed the genetic findings of the proband and all screened family members in which to the best of our knowledge, the first study using the whole-exome sequencing technique to identify the causative gene mutations for familial hypercholesterolaemia among the Malaysian population.

Genetic and Clinical Characteristics of Patients With Homozygous and Compound Heterozygous Familial Hypercholesterolemia From Three Different Populations: Case Series.

Homozygous familial hypercholesterolemia (HoFH) and compound heterozygous familial hypercholesterolemia (cHeFH) are rare disorders generated by disease-causing variants in both alleles of the LDLR or other familial hypercholesterolemia (FH)-related genes. HoFH and cHeFH are characterized by severely elevated low-density lipoprotein-cholesterol (LDL-C), frequently leading to early cardiovascular disease. We investigated the genetic and clinical characteristics of HoFH and cHeFH patients from the Slovenian FH registry and/or those who were previously diagnosed or managed at our institution (Slovenian, Pakhtun and Albanian ethnicity), where genetic testing is not available. Our study includes seven patients. Their median age at the time of clinical diagnosis was 6.3 years (2.9-12.9 years); 2/7 were females. Two patients were diagnosed through the universal FH screening and five patients were diagnosed due to the presence of xanthomas. All the mutations are present in LDLR gene: 7 different genotypes for HoFH (p.Cys167Leu, p.Asp178Asn, p.Cys243Tyr, p.Gly549Asp, p.Cys27Trp, p.Ile585Thr and p.Val797Met) and p.Gly549Asp/p.Gln384Pro genotype for cHeFH patient. The median initial level of LDL-C was 17.0 mmol/L [655 mg/dL] (range 7.6-21.6 mmol/L). The HoFH/cHeFH patients are clinically and genetically very diverse. The clinical criteria (as Simon Broome criteria) might be applicable already in children to raise suspicion of FH but in some cases fail to distinguish heterozygous FH and HoFH/cHeFH patients. However, genetic testing is helpful in confirming the diagnosis, also for a prompt awareness, better compliance to treatment and family screening.

A systematic review of LDLR, PCSK9, and APOB variants in Asia.

BACKGROUND AND AIMS: Genetic identification is a public health care concern for management of familial hypercholesterolemia (FH) associated cardiovascular morbidity and mortality. This study presents the spectrum and distribution of LDLR, APOB, PCSK9 gene mutations in Asia. METHODS: Databases were searched for English papers from 1950 to 2019. The spectrum of the variants was investigated in 8994 FH families in 48 Asian countries. We determined the frequency of variants, zygosity, and clinical features. RESULTS: Twenty countries have studied LDLR variants. A total of 629 mutations were reported and twenty variants were accounted as common variants in different populations. China, Japan, India and Taiwan constituted 68% of published articles. The most frequent mutation was reported in Japan but was not common in other countries. Other missense variants accounted for 50% of the mutations, frameshifts 19%, and nonsense 11%. The pooled frequency of variation was estimated in 1867 individuals. Approximately 67% of Iranian families were homozygous.,The common variant was p.Ser130Ter. p.Arg3527Trp in APOB was common among 184 heterozygous patients; the common variant of PCSK9 was p.Glu32Lys. CONCLUSIONS: This is the first systematic review of LDLR, APOB, PCSK9 mutations in FH patients in Asia. These findings underscore the need to fill in the gap of studies on different populations in Asia. It also underlies the importance of early detection and management to decrease atherosclerosis and cardiovascular risk in different ethnicities.

Functional analysis of new variants at the low-density lipoprotein receptor associated with familial hypercholesterolemia.

Familial hypercholesterolemia is an autosomal dominant disease of lipid metabolism caused by defects in the genes LDLR, APOB, and PCSK9. The prevalence of heterozygous familial hypercholesterolemia (HeFH) is estimated between 1/200 and 1/250. Early detection of patients with FH allows initiation of treatment, thus reducing the risk of coronary heart disease. In this study, we performed in vitro characterization of new LDLR variants found in our patients. Genetic analysis was performed by Next Generation Sequencing using a customized panel of 198 genes in DNA samples of 516 subjects with a clinical diagnosis of probable or definitive FH. All new LDLR variants found in our patients were functionally validated in CHO-ldlA7 cells. The LDLR activity was measured by flow cytometry and LDLR expression was detected by immunofluorescence. Seven new variants at LDLR were tested: c.518 G>C;p.(Cys173Ser), c.[684 G>T;694 G>T];p.[Glu228Asp;Ala232Ser], c.926C>A;p.(Pro309His), c.1261A>G;p.(Ser421Gly), c.1594T>A;p.(Tyr532Asn), and c.2138delC;p.(Thr713Lysfs*17). We classified all variants as pathogenic except p.(Ser421Gly) and p.(Ala232Ser). The functional in vitro characterization of rare variants at the LDLR is a useful tool to classify the new variants. This approach allows us to confirm the genetic diagnosis of FH, avoiding the classification as "uncertain significant variants", and therefore, carry out cascade family screening.

Polygenic Hypercholesterolemia and Cardiovascular Disease Risk.

PURPOSE OF THE REVIEW: Identification of loci and common single-nucleotide polymorphisms (SNPs) that have modest effects on plasma lipids have been used to confirm or refute the causal role of lipid traits in the development of coronary heart disease (CHD), and as tools to identify individuals with polygenic hypercholesterolemia. RECENT FINDINGS: Several groups have reported on the use of SNP scores in distinguishing individuals with a clinical diagnosis of familial hypercholesterolemia (FH) with a monogenic or polygenic etiology. We review evidence that those with monogenic FH have worse prognosis and discuss the possible mechanisms for this and their management. Individuals with a clinical phenotype of FH and a monogenic cause are at greater risk of CHD than those where no causative mutation can be found. The patients with polygenic hypercholesterolemia would not require elaborate cascade screening or secondary care input for their management.