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ABSTRACT Mobile elements (ME) can transpose by copy‐and‐paste mechanisms. A heterozygous insertion in APOB exon 3 coding sequence was suspected in a patient with hypobetalipoproteinemia (HBL), by gel electrophoresis of the PCR products. An insertion of a 85 bp fragment flanked by a polyA stretch and a target replication site duplication was identified as a ME insertion (MEI) from the AluYa5 subfamily, NM_000384.3(APOB):c.135_136ins(160). Then, the DNA was reanalyzed using our NGS custom panel. Routine analysis did not reveal any causative variant, but manual inspection of the alignments and MELT enabled us to detect this MEI from NGS data. A functional study revealed that this MEI introduces a stop codon p.(Phe46Alafs*2) and additionally leads to p.(Lys41Serfs*2) due to an exon skipping. This is the first report of a MEI into APOB, as a cause of HBL. Furthermore, our study highlights the value of including MEI‐callers in routine pipelines to improve primary dyslipidemia diagnosis. [ABSTRACT FROM AUTHOR]

Background: The goal of the study was to provide an individual and precise genetic and molecular biological basis for the early prevention, diagnosis, and treatment of local FH by analyzing the risk factors for the development of FH in Han and Mongolian patients in the Hulunbuir, comparing the lipid levels of FH patients of the two ethnicities, and assessing differences in mutations to two genes between the two ethnic groups. Methods: Twenty cases each of Han Chinese and Mongolian healthy controls and fifty patients who each met the inclusion criteria from November 2021 to December 2022 in five general hospitals in Hulunbuir were selected. Multifactor logistic analysis was used to analyze the risk factors associated with the development of FH. We used t-tests to analyze statistical differences in lipid levels between the groups, and Sanger sequencing to detect the distribution of common mutation sites of PCSK9 and APOB in all study subjects. The mutation rates and differences between regions and ethnic groups were summarized and compared. Results: 1) Gender, age, alcohol consumption, dietary status, and a family history of FH were risk factors associated with the development of FH. 2) TC, LDL-C, and APOB were significantly higher in Mongolian cases than Han cases (p < 0.05). sdLDL-C was not statistically different between the two ethnicities (p > 0.05). 3) We detected four (8%) heterozygous mutations at the PCSK9 gene E670G mutation site in the Han case group and a total of nine (18%) mutations at this site in the Mongolian cases, including one (2%) homozygous and eight (16%) heterozygous mutations. One case of a heterozygous mutation was detected in the Mongolian control group. We detected a total of ten (20%) mutations at the APOB gene rs1367117 mutation site in the Han case group, including eight (16%) heterozygous and two (4%) homozygous mutations, 11 cases (22%) of heterozygous mutations in the Mongolian case group, two cases of heterozygous mutations in the Han control group, and one case of a heterozygous mutation in the Mongolian control group. 4) The D374Y and S127R mutation sites of PCSK9 and the R3500Q mutation site of APOB were not detected in any of the study subjects. Conclusions: The mutation sites of the PCSK9 and APOB genes in FH patients in Hulunbuir are different from other regions, and the mutation rate is higher than in other regions. Therefore, we recommend that the mutation sites of the PCSK9 and APOB genes described herein be used as clinical detection indicators to assist the diagnosis of FH in this region. [ABSTRACT FROM AUTHOR]

Background: Acne vulgaris (AV) is a chronic, multifactorial inflammatory disease of the pilosebaceous unit brought on by hormonal imbalance, excessive sebum production, follicular hyperkeratinization, inflammation and Cutibacterium acne. Acne patients are characterized by alteration of the lipid profile. Apolipoprotein B gene (ApoB) plays an essential role in lipoprotein biosynthesis and multiple single‐nucleotide polymorphisms (SNPs) in ApoB are associated with dyslipidemia. Aim: The aim of this study was to estimate the alteration of lipid profiles in AV, determine the genetic association with lipid profile alteration by studying the ApoB gene polymorphisms, and to identify the exact haplotypes associated with acne and lipid profile alteration. Subjects and Methods: In a case–control study consisting of 63 non‐obese acne patients and 43 healthy controls, all participants underwent biochemical, anthropological assessments, and genetic analysis for ApoB polymorphisms. Result: Our results indicate that serum ApoB and the lipid profile were higher in acne patients compared with healthy subject. The most common haplotypes in acne patients were rs562338 A/rs17240441 I/c.12669 A/rs1042034 G, whereas the most common haplotypes in healthy subjects were rs562338 G/rs17240441 D/c.12669 A/rs1042034 G. Patients with mild acne had higher serum ApoB levels p = 0.005. Also, the low‐density lipoprotein cholesterol (LDL‐C) level was higher in mild acne compared with other acne groups, with a highly significant variation of p ≤ 0.001. Conclusion: We found a significant variation between the acne group and healthy controls in serum ApoB, triglycerides, total cholesterol and LDL‐C. The most common haplotypes in acne patients are rs562338 A/, rs17240441 I/, c.12669 A/ and rs1042034 G, and there is a linkage disequilibrium between the four selected SNPs. [ABSTRACT FROM AUTHOR]

Keywords: APOB gene; hypobetalipoproteinemia; minigene; splicing mutation EN APOB gene hypobetalipoproteinemia minigene splicing mutation e259 e262 4 10/30/23 20231101 NES 231101 To the Editor, Hypobetalipoproteinemia (HBL) is characterized by reduced plasma levels of low-density lipoprotein cholesterol (LDLc) and apolipoprotein B (ApoB) below the fifth percentile adjusted for age and sex [[1]]. Hypobetalipoproteinemia, APOB gene, minigene, splicing mutation. [Extracted from the article]

BackgroundFamilial hypobetalipoproteinemia (FHBL) is an autosomal semi-dominant disorder usually caused by variants in the APOB gene that frequently interferes with protein length. Clinical manifestations include malabsorption, non-alcoholic fatty liver disease, low levels of lipid-soluble vitamins, and neurological, endocrine, and hematological dysfunction.MethodsGenomic DNA was isolated from the blood samples of the pediatric patient with hypocholesterolemia and his parents and brother. Next-generation sequencing (NGS) was performed, and an expanded dyslipidemia panel was employed for genetic analysis. In addition, a systematic review of the literature on FHBL heterozygous patients was performed.Case reportGenetic investigation revealed the presence of a heterozygous variant in the APOB (NM_000384.3) gene c.6624dup[=], which changes the open reading frame and leads to early termination of translation into the p.Leu2209IlefsTer5 protein (NP_000375.3). The identified variant was not previously reported. Familial segregation analysis confirmed the variant in the mother of the subject, who also has a low level of low-density lipoprotein and non-alcoholic fatty liver disease. We have introduced therapy that includes limiting fats in the diet and adding lipid-soluble vitamins E, A, K, and D and calcium carbonate. We reported 35 individuals with APOB gene variations linked to FHBL in the systematic review.ConclusionWe have identified a novel pathogenic variant in the APOB gene causing FHBL in pediatric patients with hypocholesterolemia and fatty liver disease. This case illustrates the importance of genetic testing for dyslipidemias in patients with significant decreases in plasma cholesterol as we can avoid damaging neurological and ophthalmological effects by sufficient vitamin supplementation and regular follow-ups.

Abstract Background We decided to compare some inflammatory, and oxidative stress markers, as well as lipid profiles between the obese and non-obese patients with type 2 diabetes considering ApoB gene polymorphism. Methods one-hundred sixty two patients with type 2 diabetes were included in this study. ApoB genotyping was conducted by the polymerase chain reaction. Serum interleukin-(IL-18), pentraxin-3 (PTX-3), and high sensitive- C reactive protein (hs-CRP) was measured as the inflammatory markers. Moreover, copper-zinc superoxide dismutase (Cu/Zn-SOD), total antioxidant capacity (TAC) and 8-isoprostane F2α were analyzed for oxidative stress assessment. Anthropometric indices and lipid profiles were measured. Results Adjusted for confounders, serum hs-CRP (p = 0.04), LDL-C (p = 0.01), LDL-C/HDL-C (p = 0.04), and TG (p = 0.02) were significantly lower at the Homozygous Insertion (Ins)/Ins vs. deletion (Del) allele carriers in the obese patients. Serum TAC was significantly lower at the obese Del allele carriers than Ins/Ins Homozygous (p = 0.03). Serum hs-CRP (p = 0.006), and 8-IsoprostanF2α (P = 0.04) were significantly higher in the obese Del allele carriers than non-obese. Serum Cu/Zn-SOD was significantly higher in the non-obese Del allele carriers than obese (p = 0.04). Conclusion Inflammation, dyslipidemia, and oxidative stress are higher in the Obese Del allele carriers with type 2 diabetes which prone them to other chronic disorders.

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. [ABSTRACT FROM AUTHOR]

Apolipoprotein B (APOB) is the major part of low density lipoprotein (LDL), with two major isoforms: APOB100 and APOB48 found in the human body. Both isoforms are involved in the formation and transport of chylomicron and LDL-cholesterol. Point mutations in APOB may lead to change in protein stereochemistry, which may result in premature coronary artery disease, familial hypobetalipoproteinemia, hypocholesterolemia, mono-genic dyslipisimias and other atherogenic events in CVD. Here we evaluated the impact of all missense and non-coding single nucleotide polymorphisms (SNPs) of APOB retrieved from dbSNP using 17 different computational tools and further evaluated the structural impact of these convergent deleterious SNPs on APOB through HOPE. We found 9 missenses, 15 intronic or regulatory region SNPs and 2 were found in miRNA target sites of APOB. Out of these variant, the rs13306194 (Arg532Trp) was found in the conserved region of protein domain, which can potentially disrupt overall chemical structure and function of the APOB. Six missense SNPs in the coding, and 17 SNPs in noncoding regions are proposed as novel most deleterious variants of APOB. We also try to predict the structural model of APOB through protein docking. The results indicate the applicability of in silico approach to propose the most deleterious SNPs of APOB that should be prioritize for future genetic association studies in cohort of cardiovascular patients. While their structural impact on APOB may suggest these predicted nsSNPs possibly be a better drug target and contribute to the treatment and better understanding of human cardiovascular disease. [ABSTRACT FROM AUTHOR]

Abstract Background Drug response is below genetic influence, proven by the genetic variants. Pharmacogenetics trials are performed in many diseases, including coronary artery disease. This study was designed to determine the genetic polymorphism (rs676210) Pro2739leu G > A in the lipid metabolism-related gene (ApoB gene) and its pharmacogenetic role in the response to atorvastatin drug in a sample of Iraqi population with coronary artery disease (CAD). Results Significant differences of genotype distribution in CAD patients and controls were observed in ApoB + 8216 in Iraqi population from Hardy Weinberg Analysis. It also found that dramatic difference of low-density lipoprotein (LDL-C) level in response to 40 mg/day of atorvastatin therapy, the minor allele (A) observed a greater LDL-C lowering than the wild type allele (G). In ANOVA analysis, the result showed that the rs676210, Pro2739Leu, in ApoB gene increased non significantly, but gradually in plasma level of total cholesterol (TC), triglyceride (TG), very low-density lipoprotein (VLDL), and oxidize low-density lipoprotein (oxLDL) in the order of genotype AA, GA, and GG in response to 40 mg atorvastatin. Conclusion We found the results highlighted the function of the rs676210, Pro2739Leu, in the ApoB gene in CAD etiology, and the findings support this variant’s impact in predicting the response of (LDL-C) to 40 mg of atorvastatin therapy. ApoB gene polymorphism (rs676210, Pro2739Leu), specifically the AA genotype, may help to identify individuals who will profit from atorvastatin's lowering effects.

Background: We decided to compare some inflammatory, and oxidative stress markers, as well as lipid profiles between the obese and non-obese patients with type 2 diabetes considering ApoB gene polymorphism. Methods: one-hundred sixty two patients with type 2 diabetes were included in this study. ApoB genotyping was conducted by the polymerase chain reaction. Serum interleukin-(IL-18), pentraxin-3 (PTX-3), and high sensitive- C reactive protein (hs-CRP) was measured as the inflammatory markers. Moreover, copper-zinc superoxide dismutase (Cu/Zn-SOD), total antioxidant capacity (TAC) and 8-isoprostane F2α were analyzed for oxidative stress assessment. Anthropometric indices and lipid profiles were measured. Results: Adjusted for confounders, serum hs-CRP (p = 0.04), LDL-C (p = 0.01), LDL-C/HDL-C (p = 0.04), and TG (p = 0.02) were significantly lower at the Homozygous Insertion (Ins)/Ins vs. deletion (Del) allele carriers in the obese patients. Serum TAC was significantly lower at the obese Del allele carriers than Ins/Ins Homozygous (p = 0.03). Serum hs-CRP (p = 0.006), and 8-IsoprostanF2α (P = 0.04) were significantly higher in the obese Del allele carriers than non-obese. Serum Cu/Zn-SOD was significantly higher in the non-obese Del allele carriers than obese (p = 0.04). Conclusion: Inflammation, dyslipidemia, and oxidative stress are higher in the Obese Del allele carriers with type 2 diabetes which prone them to other chronic disorders. [ABSTRACT FROM AUTHOR]

Background: Drug response is below genetic influence, proven by the genetic variants. Pharmacogenetics trials are performed in many diseases, including coronary artery disease. This study was designed to determine the genetic polymorphism (rs676210) Pro2739leu G > A in the lipid metabolism-related gene (ApoB gene) and its pharmacogenetic role in the response to atorvastatin drug in a sample of Iraqi population with coronary artery disease (CAD). Results: Significant differences of genotype distribution in CAD patients and controls were observed in ApoB+ 8216 in Iraqi population from Hardy Weinberg Analysis. It also found that dramatic difference of low-density lipoprotein (LDL-C) level in response to 40 mg/day of atorvastatin therapy, the minor allele (A) observed a greater LDL-C lowering than the wild type allele (G). In ANOVA analysis, the result showed that the rs676210, Pro2739Leu, in ApoB gene increased non significantly, but gradually in plasma level of total cholesterol (TC), triglyceride (TG), very low-density lipoprotein (VLDL), and oxidize low-density lipoprotein (oxLDL) in the order of genotype AA, GA, and GG in response to 40 mg atorvastatin. Conclusion: We found the results highlighted the function of the rs676210, Pro2739Leu, in the ApoB gene in CAD etiology, and the findings support this variant's impact in predicting the response of (LDL-C) to 40 mg of atorvastatin therapy. ApoB gene polymorphism (rs676210, Pro2739Leu), specifically the AA genotype, may help to identify individuals who will profit from atorvastatin's lowering effects. [ABSTRACT FROM AUTHOR]

The first studies of familial hypercholesterolemia (FH) in Russia go back to late 1980-ies. For more than 10 years the research in this field was carried out in Saint-Petersburg, the megapolis in the North-West Russia. Studies were focused on the search for causative mutations in low-density lipoprotein receptor gene (LDLR). Gradually the research was spread to Petrozavodsk in Karelia and in the XXI century two more centers contributed in investigations of genetics of FH, i.e., in Moscow and Novosibirsk. The best studied is the spectrum of mutations in LDLR, though genetic abnormalities in APOB and PCSK9 genes were also considered. Despite that some 40% mutations in LDLR found in Saint-Petersburg and Moscow are referred to as specific for Russian population, and this proportion is even higher in Karelia (ca. 70%), rapid introduction of NGS and intensifying genetic research all over the world result in continuous decrease of these numbers as “Slavic” mutations become documented in other countries. The samplings of genetically characterized patients in Russia were relatively small, which makes difficult to specify major mutations reflecting the national specificity of FH. Moreover, the majority of studies accomplished so far did not explore possible associations of certain mutations with ethnic origin of patients. By now the only exception is the study of Karelian population showing the absence of typical Finnish mutations in the region that borders on Finland. It can be concluded that the important primary research partly characterizing the mutation spectrum in FH patients both in the European and Siberian parts of Russia has been done. However, it seems likely that the most interesting and comprehensive genetic studies of FH in Russia, concerning various mutations in different genes and the variety of ethnic groups in this multi-national country, are still to be undertaken.

Abstract Genes can influence lipid profile and anthropometric variables related to obesity. The present study aimed to verify if variants of the APOE, APOB, ADIPOQ, HSD11β1, and PLIN4 genes are associated with lipid levels or anthropometric variables in a sample comprised of 393 Euro-Brazilian children and adolescents. DNA was genotyped by TaqMan allelic discrimination assay. The ε4 and ε2 alleles of the APOE gene were associated respectively with lower high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels (p=0.015 and p=0.012, respectively), while the ε3 allele was associated with higher abdominal circumference (p=0.0416) and excess weight (p=0.0001). The G allele (rs846910) of the HSD11β1 gene was also associated with excess weight (p=0.039). No other association was found. Our results indicate that the ε4 and ε2 alleles could contribute to lower HDL-C and LDL-C levels, respectively, furthermore, the ε3 allele and the G allele (rs846910) of HSD11β1 gene may be risk factors for excess of weight.These findings are very important because we observed that some genetic variants influence the lipid profile and anthropometric variables early in life.

The first studies of familial hypercholesterolemia (FH) in Russia go back to late 1980-ies. For more than 10 years the research in this field was carried out in Saint-Petersburg, the megapolis in the North-West Russia. Studies were focused on the search for causative mutations in low-density lipoprotein receptor gene (LDLR). Gradually the research was spread to Petrozavodsk in Karelia and in the XXI century two more centers contributed in investigations of genetics of FH, i.e., in Moscow and Novosibirsk. The best studied is the spectrum of mutations in LDLR , though genetic abnormalities in APOB and PCSK9 genes were also considered. Despite that some 40% mutations in LDLR found in Saint-Petersburg and Moscow are referred to as specific for Russian population, and this proportion is even higher in Karelia (ca. 70%), rapid introduction of NGS and intensifying genetic research all over the world result in continuous decrease of these numbers as "Slavic" mutations become documented in other countries. The samplings of genetically characterized patients in Russia were relatively small, which makes difficult to specify major mutations reflecting the national specificity of FH. Moreover, the majority of studies accomplished so far did not explore possible associations of certain mutations with ethnic origin of patients. By now the only exception is the study of Karelian population showing the absence of typical Finnish mutations in the region that borders on Finland. It can be concluded that the important primary research partly characterizing the mutation spectrum in FH patients both in the European and Siberian parts of Russia has been done. However, it seems likely that the most interesting and comprehensive genetic studies of FH in Russia, concerning various mutations in different genes and the variety of ethnic groups in this multi-national country, are still to be undertaken. [ABSTRACT FROM AUTHOR]

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. 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. 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). 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. [ABSTRACT FROM AUTHOR]

Familial hypobetalipoproteinaemia is a disorder of lipid metabolism characterized by low levels of total cholesterol, low-density lipoprotein cholesterol and apolipoprotein B. ApoB-related familial hypolipoproteinemia is an autosomal condition with a codominance inheritance pattern. Non-classical congenital adrenal hyperplasia is an autosomal recessive disorder due to mutations in the CYP21A2, a gene encoding for the enzyme 21-hydroxylase, which results in an androgen excess production from adrenal source. We here present the case of a 25-year-old woman with NCAH showing decreased levels of total-cholesterol, low-density lipoprotein cholesterol and triglycerides. Her parent had digestive symptoms and severe hepatic steatosis with elevated liver enzymes, as well as decreased levels of total and low-density lipoprotein cholesterol. A genetic-molecular study of the proband identified a mutation in the APOB gene, which allowed a diagnosis of heterozygous ApoB-related hypolipoproteinaemia to be made., (Copyright © 2023 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.)

The incidence rate of Parkinson's disease ranks the second among degenerative diseases of the nervous system, only lower than Alzheimer's disease. Early-onset Parkinson's disease (EPOD) refers to Parkinson's disease with initial symptoms appearing before the age of 50. EOPD is associated with certain genetic mutations and has distinct clinical features. This study reports a case of EOPD with mutations in both the PRKN and the APOB genes. The patient presented with the initial symptom of unstable walking at the age of 28, followed by bradykinesia, limb tremors, masked face, shuffling gait, and cogwheel rigidity in both upper limbs. The blood lipid test showed total cholesterol of 6.48 mmol/L and low-density lipoprotein cholesterol of 4.13 mmol/L. Genetic testing showed a deletion in exon 5 and a point mutation [c.850G>C(p.Gly284Arg)] in exon 7 of the PRKN gene, as well as a point mutation [c.10579C>T(p.Arg3527Trp)] in exon 26 of the APOB gene. Based on these clinical manifestations and examination results, the patient was diagnosed with EOPD. The compound heterozygous mutations in the PRKN gene, as well as the combined mutations in the PRKN and APOB genes, are both reported for the first time, expanding the spectrum of genetic mutations associated with EOPD.

Familial hypobetalipoproteinemia (FHBL) is a codominant genetic disorder characterized by reduced plasma levels of low-density lipoprotein cholesterol and apolipoprotein B. To our knowledge, no study on FHBL in Lebanon and the Middle East region has been reported. Therefore, we conducted genetic studies in unrelated families and probands of Lebanese origin presenting with FHBL, in order to identify the causes of this disease. We found that 71% of the recruited probands and their affected relatives were heterozygous for the p.(Arg490Trp) variant in the APOB gene. Haplotype analysis showed that these patients presented the same mutant haplotype. Moreover, there was a decrease in plasma levels of PCSK9 in affected individuals compared to the non-affected and a significant positive correlation between circulating PCSK9 and ApoB levels in all studied probands and their family members. Some of the p.(Arg490Trp) carriers suffered from diabetes, hepatic steatosis or neurological problems. In conclusion, the p.(Arg490Trp) pathogenic variant seems a cause of FHBL in patients from Lebanese origin, accounting for approximately 70% of the probands with FHBL presumably as a result of a founder mutation in Lebanon. This study is crucial to guide the early diagnosis, management and prevention of the associated complications of this disease.

Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1. • APOB gene variants may be the cause of familial hypobetalipoproteinemia (FHBL-1). • Six rare APOB intronic variants involving splice sites were found in FHBL-1 subjects. • The functional impact of each variant was assessed in vitro using minigene strategy. • Four variants were found to generate abnormal transcripts encoding truncated apoBs. [ABSTRACT FROM AUTHOR]

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. Summary: 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • Consumption of extra virgin olive oil (EVOO) decreased food intake. • The interaction between the Eastern diet and EVOO led to LIPC expression increase. • EVOO and the Eastern diet had independent effects lowering triglyceride levels. • EVOO nutrigenomic effects were restricted to an Eastern human-based diet. Some nutrigenomic effects of extra virgin olive oil (EVOO) are described in the literature; however, it is unknown whether its interaction with lipid-related genes is independent of the combined diet. In this sense, our objective was to investigate whether EVOO consumption associated with Western or Eastern human-based chow modulates the expression of APOE , APOB , and LIPC genes in rats. In view of this, the hypothesis is that the consumption of olive oil may not have the same nutrigenomic effects, depending on the diet consumed. For this study, 56 female rats were randomly divided into four groups: Western diet with EVOO (WS), Western-diet control (WC), Eastern-diet with EVOO (ES), and Eastern-diet control (EC). After 15 weeks, the animals were anesthetized with an intraperitoneal injection of chloral hydrate 15% (1.5 mL/kg) and euthanized by guillotining, and adipose tissue, liver, and blood were extracted. Triglycerides, cholesterol, and glucose levels were obtained following standard protocols, and relative gene expressions were calculated using the ΔΔCt method after quantitative PCR. The EVOO consumption was associated with LIPC gene expression increase in the liver only in animals fed the Eastern diet, compared to EC and WS animals. The EVOO consumption, combined with the Eastern diet, was associated with decreased triglyceride levels compared to WC. Although final weight and weight gain were similar between groups, WS animals had lower daily energy consumption. Conclusion: Given these results, the authors suggested that the EVOO nutrigenomic effects were restricted to an Eastern human-based diet. [ABSTRACT FROM AUTHOR]

The RNA interference pathway (RNAi) is a specific and powerful biological process, triggered by small non-coding RNA molecules and involved in gene expression regulation. In this work, we explored the possibility of increasing the biological stability of these RNA molecules by replacing their natural ribose ring with an acyclic L-threoninol backbone. In particular, this modification has been incorporated at certain positions of the oligonucleotide strands and its effects on the biological properties of the siRNA have been evaluated. In vitro cellular RNAi assays have demonstrated that the L-threoninol backbone is well tolerated by the RNAi machinery in both double and single-stranded fashion, with activities significantly higher than those evinced by the unmodified RNAs and comparable to the well-known phosphorothioate modification. Additionally, this modification conferred extremely strong resistance to serum and 3′/5′-exonucleases. In view of these results, we applied this modification to the knockdown of a therapeutically relevant human gene such as apolipoprotein B (ApoB). Further studies on the activation of the innate immune system showed that L-threoninol-modified RNAs are slightly less stimulatory than unmodified RNAs.

Background The most frequent monogenic causes of low plasma cholesterol are familial hypobetalipoproteinemia (FHBL1) because of truncating mutations in apolipoprotein B coding gene ( APOB ) and familial combined hypolipidemia (FHBL2) due to loss-of-function mutations in ANGPTL3 gene. Objective A direct comparison of lipid phenotypes of these 2 conditions has never been carried out. In addition, although an increased prevalence of liver steatosis in FHBL1 has been consistently reported, the hepatic consequences of FHBL2 are not well established. Methods We investigated 350 subjects, 67 heterozygous carriers of APOB mutations, 63 carriers of the p.S17* mutation in ANGPTL3 (57 heterozygotes and 6 homozygotes), and 220 noncarrier normolipemic controls. Prevalence and degree of hepatic steatosis were assessed by ultrasonography. Results A steady decrease of low-density lipoprotein cholesterol levels were observed from heterozygous to homozygous FHBL2 and to FHBL1 individuals, with the lowest levels in heterozygous FHBL1 carrying truncating mutations in exons 1 to 25 of APOB ( P for trend <.001). Plasma triglycerides levels were similar in heterozygous FHBL1 and homozygous FHBL2 individuals, but higher in heterozygous FHBL2. The lowest high-density lipoprotein cholesterol levels were detected in homozygous FHBL2 ( P for trend <.001). Compared with controls, prevalence and severity of hepatic steatosis were increased in heterozygous FHBL1 ( P < .001), but unchanged in FHBL2 individuals. Conclusion Truncating APOB mutations showed the more striking low-density lipoprotein cholesterol lowering effect compared with p.S17* mutation in ANGPTL3 . Reduced high-density lipoprotein cholesterol levels were the unique lipid characteristic associated with FHBL2. Mutations impairing liver synthesis or secretion of apolipoprotein B are crucial to increase the risk of liver steatosis. [ABSTRACT FROM AUTHOR]

Apolipoprotein B (ApoB) is a major protein component of plasma lipoproteins. It is involved in many important biological processes such as lipid transportation, enzyme activity regulation, and receptor recognition. Extensive studies have shown that the expression of ApoB is regulated at multiple levels. However, the regulation of ApoB expression by microRNAs (miRNAs) still remains unknown. In the present study, identified are miRNAs that are predicted to interact with ApoB in chicken. The predicted relationship between the identified miRNAs and ApoB was verified through dual luciferase reporter assay in chicken DF1 cells, and the effect of miRNAs on ApoB expression was analyzed in chicken embryo hepatocytes stimulated by 17β-estradiol. The results show that miR-101-2-5p was predicted to interact with ApoB. Dual luciferase reporter assay together with the miR-101-2-5p mimics study demostrate that ApoB is the target of miR-101-2-5p, which suppresses the expression of ApoB through binding with the 3′UTR of ApoB. Our experiments suggest that miR-101-2-5p might be involved in lipid metabolism through binding to the 3′UTR of ApoB in the liver of egg-laying chickens. [ABSTRACT FROM AUTHOR]

Purpose of Review: Familial hypercholesterolaemia (FH) is an inherited disorder of low-density lipoprotein cholesterol (LDL-C) which is characterised by a raised cholesterol level from birth and a high risk of premature coronary heart disease. In this paper, we review the genetic basis of FH and its impact on the clinical presentation. Recent Findings: Mutations in any of three genes ( LDLR, APOB and PCSK9) are known to cause autosomal dominant FH, but a mutation can be found in only ∼40% of patients with a clinical diagnosis of FH. In the remainder, a polygenic aetiology is most likely, due to the co-inheritance of common LDL-C-raising variants. The cardiovascular presentation and management of FH will differ between patients based on their underlying genetic factors. Summary: New genotyping methods such as next-generation sequencing will provide us with better understanding of the genetic architecture of FH. [ABSTRACT FROM AUTHOR]

Diarrhoea is a common clinical problem for treating clinicians in developing countries. Mostly, it is attributed to malnutrition and infection. We, as clinicians, tend to miss some of cases who have inherited enteropathies because of lack of suspicion and non availability of diagnostic facilities. Here, we report a case of homozygous hypobetalipoproteinaemia in a nine-month-old female patient presenting with chronic diarrhoea and failure to thrive. Simple parental screening of lipid parameters led to correct diagnosis and early intervention in present case.

Monogenically inherited hypercholesterolemia is most commonly caused by mutations at the low density lipoprotein receptor (LDLR) locus causing familial hypercholesterolemia (FH) or at the apolipoprotein B (APOB) locus causing the disorder familial defective apoB (FDB). Probands from 47 kindreds with a strict clinical diagnosis of FH were selected from the Cardiovascular Genetics Research Lipid Clinic, Utah, for molecular genetic analysis. Using a combination of single-strand conformation polymorphism (SSCP) and direct sequencing, 12 different LDLR gene mutations were found in 16 of the probands. Three of the probands were carriers of the APOB R3500Q mutation. In five of the remaining 28 pedigrees where no mutation had been detected, samples from enough relatives were available to examine co-segregation with the LDLR region using the microsatellite marker D19S221, which is within 1 Mb centromeric of the LDLR locus, and D19S394, sited within 150 kb telomeric of the LDLR locus. In four of the families there was strong evidence for co-segregation between the LDLR locus and the phenotype of hypercholesterolemia, but in one large family with 18 living affected members and clear-cut bimodal hypercholesterolemia, there were numerous exclusions of co-segregation. Using length polymorphic markers within and outside the APOB gene, linkage of phenotype in this family to the APOB region was similarly excluded. In this large family, the degree of hypercholesterolemia, prevalence of tendon xanthomata, and occurrence of early coronary disease were indistinguishable from the other families studied. In summary, the data provide unequivocal evidence that a third locus can be etiological for monogenic familial hypercholesterolemia and should be reinvigorating to research in this field.—Haddad, L., I. N. M. Day, S. Hunt, R. R. Williams, S. E. Humphries, and P. N. Hopkins. Evidence for a third genetic locus causing familial hypercholesterolemia: a non-LDLR, non-APOB kindred. J. Lipid Res. 1999. 40: 1113–1122.

Background: Apolipoprotein (apo)B is the structural apoprotein of intestinally- and liver- derived lipoproteins and plays an important role in the transport of triacylglycerol (TAG) and cholesterol. Previous studies have examined the association between the APOB insertion/deletion (ins/del) polymorphism (rs17240441) and postprandial lipaemia in response to a single meal; however the findings have been inconsistent with studies often underpowered to detect genotype-lipaemia associations, focused mainly on men, or with limited postprandial characterisation of participants. In the present study, using a novel sequential test meal protocol which more closely mimics habitual eating patterns, we investigated the impact of APOB ins/del polymorphism on postprandial TAG, non-esterified fatty acids, glucose and insulin levels in healthy adults. Findings: Healthy participants (n = 147) consumed a standard test breakfast (0 min; 49 g fat) and lunch (330 min; 29 g fat), with blood samples collected before (fasting) and on 11 subsequent occasions until 480 min after the test breakfast. The ins/ins homozygotes had higher fasting total cholesterol, LDL-cholesterol, TAG, insulin and HOMA-IR and lower HDL-cholesterol than del/del homozygotes (P < 0.017). A higher area under the time response curve (AUC) was evident for the postprandial TAG (P < 0.001) and insulin (P = 0.032) responses in the ins/ins homozygotes relative to the del/del homozygotes, where the genotype explained 35% and 7% of the variation in the TAG and insulin AUCs, respectively. Conclusions: In summary, our findings indicate that the APOB ins/del polymorphism is likely to be an important genetic determinant of the large inter-individual variability in the postprandial TAG and insulin responses to dietary fat intake. [ABSTRACT FROM AUTHOR]

The RNA interference pathway (RNAi) is a specific and powerful biological process, triggered by small non-coding RNA molecules and involved in gene expression regulation. In this work, we explored the possibility of increasing the biological stability of these RNA molecules by replacing their natural ribose ring with an acyclic L-threoninol backbone. In particular, this modification has been incorporated at certain positions of the oligonucleotide strands and its effects on the biological properties of the siRNA have been evaluated. In vitro cellular RNAi assays have demonstrated that the L-threoninol backbone is well tolerated by the RNAi machinery in both double and single-stranded fashion, with activities significantly higher than those evinced by the unmodified RNAs and comparable to the well-known phosphorothioate modification. Additionally, this modification conferred extremely strong resistance to serum and 3'/5'-exonucleases. In view of these results, we applied this modification to the knockdown of a therapeutically relevant human gene such as apolipoprotein B (ApoB). Further studies on the activation of the innate immune system showed that L-threoninol-modified RNAs are slightly less stimulatory than unmodified RNAs. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To study correlation between the Xba I polymorphism of apoB gene and plasma lipid profiles in Li ethnic group. Methods: Total 151 cases of healthy Li people were recruited randomly by cluster sampling and 200 Han people were recruited as control; blood was drawn to analyze Xba I polymorphism distribution of apoB gene and serum lipid levels. Results: There were lower serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels in serum of Li people; while, high density lipoprotein cholesterol (HDL-C), X−/X+ genotype and X+ allele frequencies exhibited higher levels than Han people. Interestingly, HDL-C level was reduced, while LDL-C level was enhanced in subjects carrying heterozygous (X−/X+) genotype compared to homozygous (X−/X−) genotype. Additionally, there were no difference in serum level of triglyceride, TC, apoprotein A (apo A) and apoprotein B (apo B) between Li and Han people, the same results were showed between X−/X+ and X−/X− genotype carriers. Conclusions: Xba I polymorphism of apoB gene is correlated to the profiles of serum lipid level, X−/X+ genotype carriers are phenotyped with higher LDL-C level and lower level of HDL-C in Li ethnic group. [Copyright &y& Elsevier]

Familial hypercholesterolemia (FH) is a genetic disorder that may lead to premature coronary heart disease (CHD) and sudden cardiac death (SCD). Mutations in the LDLR or APOB genes cause FH. We have screened the LDLR and the ligand-binding region of APOB genes in 52 cases of SCD. Deceased patients were younger than 40 years of age and were suspected of having FH. The LDLR and APOB genes were examined via PCR, high-resolution melting, and DNA sequencing. Therein, it was observed that 7.7% of the screened patients exhibited a rare sequence variant in the LDLR gene, with 5.7% suspected of being pathogenic mutations. Lipid profiles and genetic testing for FH could be considered when autopsy reveals significant atherosclerosis of the coronary arteries in young adults. First-degree family members are advised to seek medical advice and testing to determine their own risks of atherosclerosis to prevent premature CHD and SCD. [ABSTRACT FROM AUTHOR]