Diagnostic Yield and Clinical Utility of Sequencing Familial Hypercholesterolemia Genes in Patients With Severe Hypercholesterolemia

Familial hypercholesterolemia (FH) is caused predominately by variants in the low-density lipoprotein receptor gene (LDLR). We report here an update of the UCL LDLR variant database to include variants reported in the literature and in-house between 2008 and 2010, transfer of the database to LOVDv.2.0 platform (https://grenada.lumc.nl/LOVD2/UCL-Heart/home.php?select_db=LDLR) and pathogenicity analysis. The database now contains over 1288 different variants reported in FH patients: 55% exonic substitutions, 22% exonic small rearrangements ( 100 bp), 2% promoter variants, 10% intronic variants and 1 variant in the 3' untranslated sequence. The distribution and type of newly reported variants closely matches that of the 2008 database, and we have used these variants (n= 223) as a representative sample to assess the utility of standard open access software (PolyPhen, SIFT, refined SIFT, Neural Network Splice Site Prediction Tool, SplicePort and NetGene2) and additional analyses (Single Amino Acid Polymorphism database, analysis of conservation and structure and Mutation Taster) for pathogenicity prediction. In combination, these techniques have enabled us to assign with confidence pathogenic predictions to 8/8 in-frame small rearrangements and 8/9 missense substitutions with previously discordant results from PolyPhen and SIFT analysis. Overall, we conclude that 79% of the reported variants are likely to be disease causing.

Low-density lipoprotein receptor gene familial hypercholesterolemia variant database: update and pathological assessment.

Overview of the current status of familial hypercholesterolaemia care in over 60 countries - The EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC).

Universal Screening for Familial Hypercholesterolemia in Children

Molecular characterization of familial hypercholesterolemia in Spain.

Autosomal dominant hypercholesterolemia (ADH) is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9). In this study, a molecular analysis ofLDLR andAPOB was performed in a group of 378 unrelated ADH patients, to explore the mutation spectrum that causes hypercholesterolemia in Poland. All patients were clinically diagnosed with ADH according to a uniform protocol and internationally accepted WHO criteria. Mutational analysis included all exons, exon-intron boundaries and the promoter sequence of theLDLR, and a fragment of exon 26 ofAPOB. Additionally, the MLPA technique was applied to detect rearrangements withinLDLR. In total, 100 sequence variations were identified in 234 (62%) patients. WithinLDLR, 40 novel and 59 previously described sequence variations were detected. Of the 99LDLR sequence variations, 71 may be pathogenic mutations. The most frequentLDLR alteration was a point mutation p.G592E detected in 38 (10%) patients, followed by duplication of exons 4–8 found in 16 individuals (4.2%). Twenty-five cases (6.6%) demonstrated the p.R3527Q mutation ofAPOB. Our findings imply that major rearrangements of theLDLR gene as well as 2 point mutations (p.G592E inLDLR and p.R3527Q inAPOB) are frequent causes of ADH in Poland. However, the heterogeneity ofLDLR mutations detected in the studied group confirms the requirement for complex molecular studies of Polish ADH patients.

Molecular characterization of Polish patients with familial hypercholesterolemia: novel and recurrent LDLR mutations.

The overall prevalence of germline BRCA1/2 mutations is estimated between 11% and 15% of all ovarian cancers. Individuals with germline BRCA1/2 alterations treated with the PARP1 inhibitors (iPARP1) tend to respond better than patients with wild-type BRCA1/2. Additionally, also somatic BRCA1/2 alterations induce the sensitivity to iPARP1. Therefore, the detection of both germline and somatic BRCA1/2 mutations is required for effective iPARP1 treatment. The aim of this study was to identify the frequency and spectrum of germline and somatic BRCA1/2 alterations in a group of Polish patients with ovarian serous carcinoma. In total, 100 formalin-fixed paraffin-embedded (FFPE) ovarian serous carcinoma tissues were enrolled to the study. Mutational analysis of BRCA1/2 genes was performed by using next-generation sequencing. The presence of pathogenic variants was confirmed by Sanger sequencing. In addition, to confirm the germline or somatic status of the mutation, the nonneoplastic tissue was analyzed by bidirectional Sanger sequencing. In total, 27 (28% of patient samples) mutations (20 in BRCA1 and 7 in BRCA2) were identified. For 22 of 27 patients, nonneoplastic cells were available and sequencing revealed the somatic character of two BRCA1 (2/16; 12.5%) and two BRCA2 (2/6; 33%) mutations. Notably, we identified six novel frameshift or nonsense BRCA1/2 mutations. The heterogeneity of the detected mutations confirms the necessity of simultaneous analysis of BRCA1/2 genes in all patients diagnosed with serous ovarian carcinoma. Moreover, the use of tumor tissue for mutational analysis allowed the detection of both somatic and germline BRCA1/2 mutations.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cam4.748

Detection of somatic BRCA1/2 mutations in ovarian cancer – next‐generation sequencing analysis of 100 cases

Efficacy of clinical diagnostic criteria for familial hypercholesterolemia genetic testing in Poland

Molecular basis of familial hypercholesterolemia in Poland – update from the Polish national centre of diagnostics and treatment of familial hypercholesterolemia

M. Zuk

Papers

Molecular characterization of Polish patients with familial hypercholesterolemia: novel and recurrent LDLR mutations.

Detection of somatic BRCA1/2 mutations in ovarian cancer – next‐generation sequencing analysis of 100 cases

Efficacy of clinical diagnostic criteria for familial hypercholesterolemia genetic testing in Poland

Molecular basis of familial hypercholesterolemia in Poland – update from the Polish national centre of diagnostics and treatment of familial hypercholesterolemia