scholarly journals Two Novel Disease-Causing Mutations in the LDLR of Familial Hypercholesterolemia

2021 ◽  
Vol 12 ◽  
Author(s):  
Haochang Hu ◽  
Tian Shu ◽  
Jun Ma ◽  
Ruoyu Chen ◽  
Jian Wang ◽  
...  

As an autosomal dominant disorder, familial hypercholesterolemia (FH) is mainly caused by pathogenic mutations in lipid metabolism-related genes. The aim of this study is to investigate the genetic mutations in FH patients and verify their pathogenicity. First of all, a pedigree investigation was conducted in one family diagnosed with FH using the Dutch Lipid Clinic Network criteria. The high-throughput sequencing was performed on three family members to explore genetic mutations. The effects of low-density lipoprotein receptor (LDLR) variants on their expression levels and activity were further validated by silico analysis and functional studies. The results revealed that LDLC levels of the proband and his daughter were abnormally elevated. The whole-exome sequencing and Sanger sequencing were used to confirm that there were two LDLR missense mutations (LDLR c.226 G > C, c.1003 G > T) in this family. Bioinformatic analysis (Mutationtaster) indicated that these two mutations might be disease-causing variants. In vitro experiments suggested that LDLR c.226 G > C and c.1003 G > T could attenuate the uptake of Dil-LDL by LDLR. In conclusion, the LDLR c.226 G > C and c.1003 G > T variants might be pathogenic for FH by causing uptake dysfunction of the LDLR.

2021 ◽  
Vol 10 (4) ◽  
pp. 749
Author(s):  
Fernando Sabatel-Pérez ◽  
Joaquín Sánchez-Prieto ◽  
Víctor Manuel Becerra-Muñoz ◽  
Juan Horacio Alonso-Briales ◽  
Pedro Mata ◽  
...  

The majority of familial hypercholesterolemia index cases (FH-IC) remain underdiagnosed and undertreated because there are no well-defined strategies for the universal detection of FH. The aim of this study was to evaluate the diagnostic yield of an active screening for FH-IC based on centralized analytical data. From 2016 to 2019, a clinical screening of FH was performed on 469 subjects with severe hypercholesterolemia (low-density lipoprotein cholesterol ≥220 mg/dL), applying the Dutch Lipid Clinic Network (DLCN) criteria. All patients with a DLCN ≥ 6 were genetically tested, as were 10 patients with a DLCN of 3–5 points to compare the diagnostic yield between the two groups. FH was genetically confirmed in 57 of the 84 patients with DLCN ≥ 6, with a genetic diagnosis rate of 67.9% and an overall prevalence of 12.2% (95% confidence interval: 9.3% to 15.5%). Before inclusion in the study, only 36.8% (n = 21) of the patients with the FH mutation had been clinically diagnosed with FH; after genetic screening, FH detection increased 2.3-fold (p < 0.001). The sequential, active screening strategy for FH-IC increases the diagnostic yield for FH with a rational use of the available resources, which may facilitate the implementation of FH universal and family-based cascade screening strategies.


2021 ◽  
Vol 23 (Supplement_D) ◽  
Author(s):  
Ashraf Reda ◽  
Ahmed Bendary ◽  
Ahmed Shawky Elserafy ◽  
Elsayed Farag ◽  
Tamer Mostafa ◽  
...  

Abstract Aims The prevalence of familial hypercholesterolemia (FH) in Egypt is largely un- known. We aimed to estimate the prevalence of FH among 3224 Egyptian patients with acute coronary syndromes enrolled from 2015 to 2018 in the nationwide cross- sectional cardioRisk project. Methods and Results We applied the Dutch Lipid Clinic criteria for the diagnosis of FH on the available data recorded for the patients enrolled in the CardioRisk project. Two main criteria were applied: the presence of premature CAD (given 2 points in the Dutch criteria), and the categorized low density lipoprotein cholesterol (LDL-C) lev- els (given 1, 3, 5, or 8 points in the Dutch criteria according to the level). From a total of 3224 patients, 2743 patients had available LDL-C levels. Among those patients, when applying the abovementioned 2 criteria, we estimated that 472 patients had at least ‘possible’ FH (17.2% of the total population). Specifically, 4 patients had ‘defi- nite’ FH (0.1%), 7 patients had ‘probable’ FH (0.25%), and 461 patients had ‘possi- ble’ FH (16.8%). Conclusion The estimated prevalence of at least ‘possible’ FH among Egyptian patients with ACS is 17%.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Keiji Matsunaga ◽  
Asako Mizobuchi ◽  
Hayato Tada ◽  
Tsuyoshi Sasaki ◽  
Yoshihiro Asano ◽  
...  

Introduction: Familial hypercholesterolemia (FH) is an autosomal hereditary disease found in patients who have elevated low-density lipoprotein cholesterol (LDL-C) from birth. Early detection and treatment of FH during childhood potentially reduces the risk of premature cardiovascular events. In Kagawa prefecture, a unique community health system, involving three steps, has been conducted to prevent lifestyle-related diseases for 10-year-old children. This system includes universal lipid screening, selection by pediatricians, and next-generation sequencing (NGS) of FH-related genes in hospitals. The aim of this study is to compare 3 international guidelines to detect pediatric FH with this unique community health system in Kagawa. Methods: In Kagawa prefecture, the universal lipid screening of approximately 8,000 children at 10 years of age is performed annually, covering over 90% of the target group. After excluding secondary hypercholesterolemia, pediatric clinics introduced children with LDL-C >140mg/dL to 4 designated hospitals to perform NGS. We applied the guidelines of the Dutch Lipid Clinic Network (DLCN), Simon Broome (SB), and the Japanese Atherosclerosis Society (JAS) to children who received NGS in the unique community health system in Kagawa. Results: We performed NGS for 46 children from January 2018 to February 2020 (LDL-C 186.0±50.3 mg/dL; Male/F 27/19) and 26 (57%) had FH genetic mutations (23 LDL-R and 3 PCSK9 mutations). Seventeen children met FH criteria for DLCN (35%), 10 for Simon Broome (22%), and 11 for JAS (24%), respectively. The combination of NGS and either of the 3 guidelines increased the number of children diagnosed as FH up to 31 (67%). Conclusion: International guidelines detected only half of pediatric FH who were diagnosed by the unique community health system in Kagawa. Further investigation will be required to build an effective universal screening system for pediatric FH.


2019 ◽  
Vol 16 (6) ◽  
pp. 467-478
Author(s):  
Ye-Xuan Cao ◽  
Bing-Yang Zhou ◽  
Di Sun ◽  
Sha Li ◽  
Yuan-Lin Guo ◽  
...  

Aim: To investigated the potential differences between probable and definite heterozygous familial hypercholesterolemia (HeFH) patients diagnosed by Dutch Lipid Clinic Network criteria. Methods: Clinical characteristics, lipid profile, severity of coronary artery stenosis and gene mutations were compared. Kaplan–Meier curve was performed to evaluate the cardiovascular events. Results: Overall, 325 participants were included and divided into two groups: probable (n = 233) and definite HeFH (n = 92). Definite HeFH patients had higher low-density lipoprotein cholesterol (LDL-C), oxidized-LDL and proprotein convertase subtilisin/kexin 9 levels, and higher prevalence of tendon xanthomas. The incidence of genetic mutations was statistically higher in definite HeFH than probable HeFH patients. The coronary stenosis calculated by Gensini score was statistically severer in definite HeFH patients. The best LDL-C threshold for predicting mutations was 5.14 mmol/l. Definite HeFH had lower event-free survival rates. Conclusion: Definite HeFH patients had higher severity of phenotype and genotype, and higher risk of cardiovascular events.


2019 ◽  
Vol 3 (8) ◽  
pp. 1461-1464 ◽  
Author(s):  
Carlo Pirazzi ◽  
Federica Tavaglione ◽  
Åsa Tivesten ◽  
Stefano Romeo

Abstract In female-to-male transgender individuals, testosterone is used to induce masculinization. Sex steroid therapy may increase circulating triglyceride and low-density lipoprotein cholesterol (LDL-C) levels and may decrease high-density lipoprotein cholesterol (HDL-C) levels, resulting in a more atherogenic lipid profile. These potentially adverse effects of androgen therapy may be exacerbated by the presence of familial hypercholesterolemia (FH). We describe the case of a transgender man with genetically diagnosed FH who was intolerant to statins and was started on a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor to control his lipoproteins more effectively. The 35-year-old female-to-male transgender individual was referred to our center with a history of elevated LDL-C levels. Despite treatment with high doses of high-potency statins and ezetimibe, he had never achieved a sustained reduction in LDL-C; his levels of LDL-C were fluctuating between 170 and 344 mg/dL (4.4 and 8.9 mmol/L). Moreover, he developed side effects to statins in the form of myalgia and discontinued statin treatment. At the Sahlgrenska Lipid Clinic, a genetic diagnosis of heterozygous FH was established, and PCSK9 inhibitor therapy was started. The patient’s LDL-C level has been reduced by approximately 40% for 23 months, and no adverse events have been reported.


2021 ◽  
Vol 11 (6) ◽  
pp. 464
Author(s):  
Alexey N. Meshkov ◽  
Alexandra I. Ershova ◽  
Anna V. Kiseleva ◽  
Svetlana A. Shalnova ◽  
Oxana M. Drapkina ◽  
...  

Heterozygous familial hypercholesterolemia (HeFH) is one of the most common genetic conditions but remains substantially underdiagnosed. The aim of our study was to investigate the prevalence of HeFH in the population of 11 different regions of Russia. Individuals were selected from the Epidemiology of Cardiovascular Risk Factors and Diseases in Regions of the Russian Federation Study. All participants who had low-density lipoprotein cholesterol (LDL-C) higher than 4.9 mmol/L, or LDL-C lower than 4.9 mmol/L, but had statin therapy, were additionally examined by FH experts. FH was diagnosed using the Dutch Lipid Clinic Network criteria, incorporating genetic testing. HeFH prevalence was assessed for 18,142 participants. The prevalence of patients with definite or probable HeFH combined was 0.58% (1 in 173). A total of 16.1% of patients with definite or probable HeFH had tendon xanthomas; 36.2% had mutations in one of the three genes; 45.6% of FH patients had coronary artery disease; 63% of HeFH patients received statins; one patient received an additional PCSK9 inhibitor; no patients received ezetimibe. Only 3% of patients reached the LDL-C goal based on 2019 ESC/EAS guidelines. Underdiagnosis and undertreatment of FH in Russia underline the need for the intensification of FH detection with early and aggressive cholesterol-lowering treatment.


Author(s):  
Roeland Huijgen ◽  
Dirk J. Blom ◽  
Merel L. Hartgers ◽  
Kévin Chemello ◽  
Asier Benito-Vicente ◽  
...  

Objective: Familial hypercholesterolemia (FH) is characterized by elevated low-density lipoprotein-cholesterol and markedly increased cardiovascular risk. In patients with a genetic diagnosis, low-density lipoprotein receptor ( LDLR ) mutations account for >90% of cases, apolipoprotein B ( APOB ) mutations for ≈5% of cases, while proprotein convertase subtilisin kexin type 9 ( PCSK9 ) gain of function mutations are rare (<1% of cases). We aimed to evaluate the functional impact of several novel PCSK9 variants in a cohort of patients with FH by genetic cascade screening and in vitro functionality assays. Approach and Results: Patients with clinically diagnosed FH underwent genetic analysis of LDLR , and if negative, sequential testing of APOB and PCSK9 . We analyzed cosegregation of hypercholesterolemia with novel PCSK9 variants. Gain of function status was determined by in silico analyses and validated by in vitro functionality assays. Among 1055 persons with clinical FH, we identified nonsynonymous PCSK9 variants in 27 (2.6%) patients and 7 of these carried one of the 4 previously reported gain of function variants. In the remaining 20 patients with FH, we identified 7 novel PCSK9 variants. The G516V variant (c.1547G>T) was found in 5 index patients and cascade screening identified 15 additional carriers. Low-density lipoprotein-cholesterol levels were higher in these 15 carriers compared with the 27 noncarriers (236±73 versus 124±35 mg/dL; P< 0.001). In vitro studies demonstrated the pathogenicity of the G516V variant. Conclusions: In our study, 1.14% of cases with clinical FH were clearly attributable to pathogenic variants in PCSK9 . Pathogenicity is established beyond doubt for the G516V variant.


Author(s):  
Ilze Radoviča ◽  
Rūdolfs Bērziņs ◽  
Gustavs Latkovskis ◽  
Dāvids Fridmanis ◽  
Liene Ņikitina-Zaķe ◽  
...  

Abstract Familial hypercholesterolemia (FH) is one of the most common single gene disorders, which is mostly inherited as an autosomal dominant trait. The physical signs of FH are elevated low density lipoprotein cholesterol (LDL-C), elevated total cholesterol (TC) levels and tendon xantomas. Identification and early treatment of affected individuals is desirable and in lack of physical symptoms DNA-based diagnosis provides confirmation of diagnosis and enables early patient management. The majority of FH cases are caused by mutations in four genes (APOB, LADLR, PCSK9, and LDLRAP1). There are commercial kits available for testing of the 20 most common FH causing mutations, but the spectrum of disease-causing mutations is quite diverse in various populations and these tests cover only a minority of disease-causing genetic variants. There is therefore a need to determine the full spectrum of mutations in LDLR, APOB, PCSK9, and LDLRAP1 genes in each population. Here we report mutations found in 16 patients with suspected FH in a sample from the Genome Database of the Latvian population enrolled at the Latvian Centre of Cardiology. We used the next generation sequencing approach to determine the full spectrum of mutations in coding regions of LDLR, APOB, PCSK9, and LDLRAP1. In total we found 22 missense mutations, from which only rs5742904 (Arg3527Gln) in APOB gene had been previously described as a FH-causing mutation confirming FH in one patient. Possible FH-causing mutations however, were identified in the majority of patients. The conclusion is that the most commonly employed commercial mutation panel is not sufficient for diagnosis of FH patients and NGS can help to identify FH-causing mutations in the Latvian population.


2021 ◽  
Vol 41 (10) ◽  
pp. 2616-2628 ◽  
Author(s):  
Eythór Björnsson ◽  
Guðmundur Thorgeirsson ◽  
Anna Helgadóttir ◽  
Guðmar Thorleifsson ◽  
Garðar Sveinbjörnsson ◽  
...  

Objective: Familial hypercholesterolemia (FH) is traditionally defined as a monogenic disease characterized by severely elevated LDL-C (low-density lipoprotein cholesterol) levels. In practice, FH is commonly a clinical diagnosis without confirmation of a causative mutation. In this study, we sought to characterize and compare monogenic and clinically defined FH in a large sample of Icelanders. Approach and Results: We whole-genome sequenced 49 962 Icelanders and imputed the identified variants into an overall sample of 166 281 chip-genotyped Icelanders. We identified 20 FH mutations in LDLR , APOB , and PCSK9 with combined prevalence of 1 in 836. Monogenic FH was associated with severely elevated LDL-C levels and increased risk of premature coronary disease, aortic valve stenosis, and high burden of coronary atherosclerosis. We used a modified version of the Dutch Lipid Clinic Network criteria to screen for the clinical FH phenotype among living adult participants (N=79 058). Clinical FH was found in 2.2% of participants, of whom only 5.2% had monogenic FH. Mutation-negative clinical FH has a strong polygenic basis. Both individuals with monogenic FH and individuals with mutation-negative clinical FH were markedly undertreated with cholesterol-lowering medications and only a minority attained an LDL-C target of <2.6 mmol/L (<100 mg/dL; 11.0% and 24.9%, respectively) or <1.8 mmol/L (<70 mg/dL; 0.0% and 5.2%, respectively), as recommended for primary prevention by European Society of Cardiology/European Atherosclerosis Society cholesterol guidelines. Conclusions: Clinically defined FH is a relatively common phenotype that is explained by monogenic FH in only a minority of cases. Both monogenic and clinical FH confer high cardiovascular risk but are markedly undertreated.


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