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1.
The pockets guide to HLA class I molecules.
Nguyen, AT, Szeto, C, Gras, S
Biochemical Society transactions. 2021;(5):2319-2331
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Abstract
Human leukocyte antigens (HLA) are cell-surface proteins that present peptides to T cells. These peptides are bound within the peptide binding cleft of HLA, and together as a complex, are recognised by T cells using their specialised T cell receptors. Within the cleft, the peptide residue side chains bind into distinct pockets. These pockets ultimately determine the specificity of peptide binding. As HLAs are the most polymorphic molecules in humans, amino acid variants in each binding pocket influences the peptide repertoire that can be presented on the cell surface. Here, we review each of the 6 HLA binding pockets of HLA class I (HLA-I) molecules. The binding specificity of pockets B and F are strong determinants of peptide binding and have been used to classify HLA into supertypes, a useful tool to predict peptide binding to a given HLA. Over the years, peptide binding prediction has also become more reliable by using binding affinity and mass spectrometry data. Crystal structures of peptide-bound HLA molecules provide a means to interrogate the interactions between binding pockets and peptide residue side chains. We find that most of the bound peptides from these structures conform to binding motifs determined from prediction software and examine outliers to learn how these HLAs are stabilised from a structural perspective.
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Single nucleotide polymorphisms in ZNRD1-AS1 increase cancer risk in an Asian population.
Wang, PY, Li, JH, Liu, YM, Lv, Q, Xie, N, Zhang, HH, Xie, SY
Oncotarget. 2017;(6):10064-10070
Abstract
Single nucleotide polymorphisms (SNPs) in human zinc ribbon domain containing 1 antisense RNA 1 (ZNRD1-AS1) have been associated with cancer development. In this meta-analysis, we more precisely estimated the associations between three expression quantitative trait loci SNPs in ZNRD1-AS1 (rs3757328, rs6940552, and rs9261204) and cancer susceptibility. The data for three SNPs were extracted from eligible studies, which included 5,293 patients and 5,440 controls. Overall, no significant associations between SNPs in ZNRD1-AS1 (rs3757328, rs6940552, and rs9261204) and cancer risk were observed. However, in further subgroup analyses based on cancer type, we found that the A allele of rs3757328 increased the risk of some cancer in both allele contrast (OR = 1.15, 95% CI = 1.05 - 1.25) and recessive models (OR = 1.79; 95% CI = 1.33 - 2.41). The A allele of rs6940552 and the G allele of rs9261204 also increased the risk of some cancer in an Asian population in allele contrast (OR = 1.17, 95% CI = 1.08 - 1.26, and OR = 1.25, 95% CI = 1.16 - 1.34, respectively) and recessive models (OR = 1.44, 95% CI = 1.18 - 1.77, and OR = 1.49; 95% CI = 1.23 - 1.80, respectively). Thus, rs3757328, rs6940552, and rs9261204 in ZNRD1-AS1 are all associated with increased some cancer risk in an Asian population.
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Mutations in the HFE gene and sporadic amyotrophic lateral sclerosis risk: a meta-analysis of observational studies.
Li, M, Wang, L, Wang, W, Qi, XL, Tang, ZY
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas. 2014;(3):215-22
Abstract
Iron homeostasis dysregulation has been regarded as an important mechanism in neurodegenerative diseases. The H63D and C282Y polymorphisms in the HFE gene may be involved in the development of sporadic amyotrophic lateral sclerosis (ALS) through the disruption of iron homeostasis. However, studies investigating the relationship between ALS and these two polymorphisms have yielded contradictory outcomes. We performed a meta-analysis to assess the roles of the H63D and C282Y polymorphisms of HFE in ALS susceptibility. PubMed, MEDLINE, EMBASE, and Cochrane Library databases were systematically searched to identify relevant studies. Strict selection criteria and exclusion criteria were applied. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. A fixed- or random-effect model was selected, depending on the results of the heterogeneity test. Fourteen studies were included in the meta-analysis (six studies with 1692 cases and 8359 controls for C282Y; 14 studies with 5849 cases and 13,710 controls for H63D). For the C282Y polymorphism, significant associations were observed in the allele model (Y vs C: OR=0.76, 95%CI=0.62-0.92, P=0.005) and the dominant model (YY+CY vs CC: OR=0.75, 95%CI=0.61-0.92, P=0.006). No associations were found for any genetic model for the H63D polymorphism. The C282Y polymorphism in HFE could be a potential protective factor for ALS in Caucasians. However, the H63D polymorphism does not appear to be associated with ALS.
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4.
HFE-associated hereditary hemochromatosis.
Alexander, J, Kowdley, KV
Genetics in medicine : official journal of the American College of Medical Genetics. 2009;(5):307-13
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Abstract
In populations of northern European descent, the p.C282Y mutation in the HFE gene is highly prevalent, and HFE-associated hereditary hemochromatosis is the most common type of inherited iron overload disorder. Inappropriate low secretion of hepcidin, which negatively regulates iron absorption, is postulated to be the mechanism for iron overload in this condition. The characteristic biochemical abnormalities are elevated serum transferrin-iron saturation and serum ferritin. Typical clinical manifestations include cirrhosis, liver fibrosis, hepatocellular carcinoma, elevated serum aminotransferase levels, diabetes mellitus, restrictive cardiomyopathy and arthropathy of the second and third metacarpophalangeal joints. Most patients are now diagnosed before the development of these clinical features. Molecular genetic tests are currently available for genotypic diagnosis. In selected individuals, diagnosis might require liver biopsy or quantitative phlebotomy. Iron depletion by phlebotomy is the mainstay of treatment and is highly effective in preventing the complications of iron overload if instituted before the development of cirrhosis. Genetic testing is currently not recommended for population screening because of low yield as the majority of the healthy, asymptomatic p.C282Y homozygotes do not develop clinically significant iron overload. HFE gene testing remains an excellent tool for the screening of first-degree relatives of affected probands who are p.C282Y homozygotes.
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5.
[HFE gene mutations and risk of hepatocellular carcinoma].
Solís Herruzo, JA, Solís Muñoz, P
Revista espanola de enfermedades digestivas. 2007;(7):369-75
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6.
HFE gene in primary and secondary hepatic iron overload.
Sebastiani, G, Walker, AP
World journal of gastroenterology. 2007;(35):4673-89
Abstract
Distinct from hereditary haemochromatosis, hepatic iron overload is a common finding in several chronic liver diseases. Many studies have investigated the prevalence, distribution and possible contributory role of excess hepatic iron in non-haemochromatotic chronic liver diseases. Indeed, some authors have proposed iron removal in liver diseases other than hereditary haemochromatosis. However, the pathogenesis of secondary iron overload remains unclear. The High Fe (HFE) gene has been implicated, but the reported data are controversial. In this article, we summarise current concepts regarding the cellular role of the HFE protein in iron homeostasis. We review the current status of the literature regarding the prevalence, hepatic distribution and possible therapeutic implications of iron overload in chronic hepatitis C, hepatitis B, alcoholic and non-alcoholic fatty liver diseases and porphyria cutanea tarda. We discuss the evidence regarding the role of HFE gene mutations in these liver diseases. Finally, we summarize the common and specific features of iron overload in liver diseases other than haemochromatosis.
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7.
Review article: the genetic basis of haemochromatosis.
Griffiths, WJ
Alimentary pharmacology & therapeutics. 2007;(3):331-42
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Abstract
BACKGROUND Since the seminal discovery of the HFE gene a decade ago, considerable further progress in unravelling the genetic basis of haemochromatosis has been made. Novel genes and iron overload phenotypes have been described with potential insights into the molecular pathophysiology of human iron metabolism. AIM: To review recent key advances in the field of inherited iron overload and assess their impact on clinical practice and on our understanding of iron regulation. METHODS A PubMed search was undertaken predominantly using 'haemochromatosis', 'HFE', 'hepcidin' and 'ferroportin'. Illustrative cases were sought. RESULTS The impact of HFE mutation analysis on the management of haemochromatosis is significant and allows early accurate diagnosis. HFE is also implicated in the siderosis associated with other liver pathologies. Non-HFE genes underpinning other forms of haemochromatosis are now recognized and genotype-phenotype interactions result in a spectrum of disease. These novel gene products interact with HFE in a common pathway for iron homeostasis. CONCLUSIONS Further identification of non-HFE genes associated with iron homeostasis will enhance our diagnostic certainty of primary haemochromatosis and may explain the variable expression seen in HFE-related disease. Improving our understanding of the mechanisms of iron regulation may lead to novel therapeutic strategies for the management of iron overload.
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Coincident natural selection of CCR5Delta32 and C282Y in Europe: to be or not to be?
Gharagozloo, M, Ghaderi, A
Journal of genetics. 2005;(1):47-8
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9.
[Update on hemochromatosis].
Loréal, O, Le Lan, C, Troadec, MB, Guyader, D, Brissot, P
Gastroenterologie clinique et biologique. 2004;(5 Suppl):D92-102
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10.
Clinical consequences of iron overload in hemochromatosis homozygotes.
Ajioka, RS, Kushner, JP
Blood. 2003;(9):3351-3; discussion 3354-8