Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

Specification of ACMG/AMP variant classification guidelines for Familial Hypercholesterolemia – a ClinGen FH Variant Curation Committee Pilot Study

Familial hypercholesterolemia (FH) is a common autosomal dominant disorder (~1:250 individuals affected) of lipid metabolism, associated with an increased risk of cardiovascular disease. Individuals with FH characteristically present with severely elevated blood cholesterol levels, which leads to atherosclerotic plaque formation and subsequently, myocardial infarction due to premature coronary artery disease. Three main causative genes have been associated with FH: LDLR, APOB and PCSK9. Diagnosis is critical for early intervention and treatment, and it is imperative that family members of affected individuals be identified as early as possible.N/

Distribution of neutrons and protons in elongated targets

Analysis of neutron distribution was carried out for two elongated targets. The targets have cylindrical shape and are made of lead and carbon, respectively. The dimensions are approximately one meter in length and 19 cm in diameter. The targets were irradiated with 660 MeV proton beam at Phasotron accelerator at the Joint Institute for Nuclear Research. The total number of protons was 2.35(18)E15 for the experiment with carbon target and the total number of particles at the second experiment was 2.32(19)E15. The produced neutron field was monitored by cobalt threshold activation detectors at various positions. The activation detectors were measured by means of gamma spectroscopy using HPGe detectors. Reaction rates of different radionuclides produced in the activation detectors were determined and the results from both experiments were compared. The ratios were calculated for 7 reactions produced in cobalt detectors. The ratio of the reaction rates shows that the number of residual nuclei with higher threshold energies is higher for experiment with carbon target than for the experiment with the lead target

Adaptation of ACMG/AMP guidelines for variant interpretation in familial hypercholesterolemia – a ClinGen FH Expert Panel pilot study

Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipid metabolism associated with premature atherosclerosis and increased cardiovascular risk. Over 3,000 variants in LDLR, APOB, and PCSK9 have been identified in FH patients; however, <10% of these have been functionally proven to cause disease. The recent ACMG/AMP guidelines for standardized variant interpretation in Mendelian disorders are being used to help further classify FH-associated variants. Despite such efforts, these existing ACMG/AMP guidelines need to be modified to become more disease-specific for FH. In 2016, the Clinical Genome Resource (ClinGen) consortium FH Expert Panel was created with the goal to develop FH-specific variant interpretation guidelinesJR Chora was funded by SFRH/BD/108503/2015. The ClinGen Consortium is funded by the NHGRI, in conjunction with additional funding from the NICHD and NCI, through the following grants and contracts: 1U41HG006834-01A1 (Rehm), 1U01HG007437-01 (Berg), 1U01HG007436-01 (Bustamante), and HHSN261200800001E.N/

Immunohistochemical assessment of phosphorylated mTORC1-pathway proteins in human brain tumors

Background: Current pathological diagnostics include the analysis of (epi-)genetic alterations as well as oncogenic pathways. Deregulated mammalian target of rapamycin complex 1 (mTORC1) signaling has been implicated in a variety of cancers including malignant gliomas and is considered a promising target in cancer treatment. Monitoring of mTORC1 activity before and during inhibitor therapy is essential. The aim of our study is to provide a recommendation and report on pitfalls in the use of phospho-specific antibodies against mTORC1-targets phospho-RPS6 (Ser235/236; Ser240/244) and phospho-4EBP1 (Thr37/46) in formalin fixed, paraffin embedded material. Methods and findings: Primary, established cell lines and brain tumor tissue from routine diagnostics were assessed by immunocyto-, immunohistochemistry, immunofluorescent stainings and immunoblotting. For validation of results, immunoblotting experiments were performed. mTORC-pathway activation was pharmacologically inhibited by torin2 and rapamycin. Torin2 treatment led to a strong reduction of signal intensity and frequency of all tested antibodies. In contrast phospho-4EBP1 did not show considerable reduction in staining intensity after rapamycin treatment, while immunocytochemistry with both phospho-RPS6-specific antibodies showed a reduced signal compared to controls. Staining intensity of both phospho-RPS6-specific antibodies did not show considerable decrease in stability in a timeline from 0–230 minutes without tissue fixation, however we observed a strong decrease of staining intensity in phospho-4EBP1 after 30 minutes. Detection of phospho-signals was strongly dependent on tissue size and fixation gradient. mTORC1-signaling was significantly induced in glioblastomas although not restricted to cancer cells but also detectable in non-neoplastic cells. Conclusion: Here we provide a recommendation for phospho-specific immunohistochemistry for patient-orientated therapy decisions and monitoring treatment response