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Background: Familial hypercholesterolemia (FH) is an autosomal dominant disorder characterized by increased LDL-cholesterol levels. About 85% of FH cases are caused by LDLR mutations encoding the low-density lipoprotein receptor (LDLR). LDLR is synthesized in the endoplasmic reticulum (ER) where it undergoes post-translational modifications and then transported through Golgi apparatus to the plasma membrane. Over 2900 LDLR variants have been reported in FH patients with limited information on the pathogenicity and functionality of many of them. This study aims to elucidate the cellular trafficking and functional implications of LDLR missense variants identified in suspected FH patients using biochemical and functional methods., Methods: We used HeLa, HEK293T, and LDLR-deficient-CHO-ldlA7 cells to evaluate the subcellular localization and LDL internalization of ten LDLR missense variants (p.C167F, p.D178N, p.C243Y, p.E277K, p.G314R, p.H327Y, p.D477N, p.D622G, p.R744Q, and p.R814Q) reported in multiethnic suspected FH patients. We also analyzed the functional impact of three variants (p.D445E, p.D482H, and p.C677F), two of which previously shown to be retained in the ER., Results: We show that p.D622G, p.D482H, and p.C667F are largely retained in the ER whereas p.R744Q is partially retained. The other variants were predominantly localized to the plasma membrane. LDL internalization assays in CHO-ldlA7 cells indicate that p.D482H, p.C243Y, p.D622G, and p.C667F have quantitatively lost their ability to internalize Dil-LDL with the others (p.C167F, p.D178N, p.G314R, p.H327Y, p.D445E, p.D477N, p.R744Q and p.R814Q) showing significant losses except for p.E277K which retained full activity. However, the LDL internalization assay is only to able evaluate the impact of the variants on LDL internalization and not the exact functional defects such as failure to bind LDL. The data represented illustrate the hypomorphism nature of variants causing FH which may explain some of the variable expressivity of FH., Conclusion: Our combinatorial approach of in silico , cellular, and functional analysis is a powerful strategy to determine pathogenicity and FH disease mechanisms which may provide opportunitites for novel therapeutic strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jawabri, John, Ghattas, Mahgoub, Hamad, Barakat, Shobi, Daggag and Ali.)

Background and Objective: Early-onset pancreatic cancer (EOPC) is associated with poor prognosis and high disease burden. Metabolic risk factors such as diabetes and obesity are considered risk factors of EOPC. Recently, there has been an increasing number of EOPCs worldwide. However, the analysis of EOPC, including its metabolic risk factors, in the Middle East and North Africa (MENA) region has not been fully addressed., Methods: Data from the Global Burden of Disease Study between 2000 and 2019 was used to analyze the prevalence, incidence, deaths and disability-adjusted life years (DALYs) associated with EOPC and its metabolic risk factors. The analysis further categorized the data based on countries, income status and sex and examined the annual percentage change (APC)., Results: Approximately 2800 cases, 2400 deaths and 114,000 DALYs were attributable to EOPC in the MENA region. The incidence (APC + 3.42%), death (APC + 0.73%) and DALYs (APC + 3.23%) rates of EOPC increased. In addition, the death and DALY rates of EOPC attributable to obesity and diabetes increased. High and upper-middle-income countries exhibited a higher burden of EOPC than lower-income countries., Conclusion: Over the past two decades, the burden of EOPC and its associated metabolic risk factors has increased. There is an urgent need for region-wide policy development, including screening methods and risk factor reduction, to mitigate the high and rising burden of EOPC in the MENA region., (© 2024. Indian Society of Gastroenterology.)