Prevalence of C282Y and H63D mutations in the hemochromatosis (HFE) gene in the United States

Novel mechanistic insights into the comorbidity of anemia and rheumatoid arthritis: Identification of therapeutic targets

OBJECTIVES

To investigate the mechanisms underlying the comorbidity of anemia and rheumatoid arthritis (RA) and identify promising therapeutic targets.

METHODS

We assessed the phenotypic linkage between anemia and RA. Using the largest genome-wide association studies (GWAS) summary statistics of European populations, we scrutinized the causal association and shared genetic architecture between the two conditions using multiple complementary approaches.

RESULTS

Logistic regression analysis confirmed a strong clinical association between anemia and RA. Using GWAS data, we identified a significant causal effect of RA on anemia and positive global genetic correlations between the two conditions (rg (genotype) = 0.28, P = 9.6 × 10-7; rg (gene expression) = 0.45, P = 2 × 10-3). After dividing the genome into 2495 independent regions, we identified 15 significant regions associated with both conditions, with 14 showing concordant effects. Fine-mapping at the SNP level revealed 72 % of RA-associated SNPs overlapped with anemia, most with concordant effects. Stratified Q-Q plots visualized the shared genetic enrichment, showing a 12-fold enrichment for RA conditional on anemia and 100-fold enrichment for anemia conditional on RA. Further analysis using conjFDR method pinpointed 14 pleiotropic loci, including several novel loci. Gene mapping identified 33 shared genes, with BLK and FAM167A further prioritized as the top two genes by SMR analysis. Enrichment analysis highlighted pathways related to inflammation, immune response, and iron metabolism. Blood and T cells showed significant tissue- and cell-type-specific enrichment.

CONCLUSIONS

This study provides novel insights into anemia-RA comorbidity mechanisms and identifies new drug targets for RA.

HFE-Related Hemochromatosis May Be a Primary Kupffer Cell Disease

Iron overload can lead to increased deposition of iron and cause organ damage in the liver, the pancreas, the heart and the synovium. Iron overload disorders are due to either genetic or acquired abnormalities such as excess transfusions or chronic liver diseases. The most common genetic disease of iron deposition is classic hemochromatosis (HH) type 1, which is caused by mutations of HFE. Other rare forms of HH include type 2A with mutations at the gene hemojuvelin or type 2B with mutations in HAMP that encodes hepcidin. HH type 3, is caused by mutations of the gene that encodes transferrin receptor 2. Mutations of SLC40A1 which encodes ferroportin cause either HH type 4A or HH type 4B. In the present review, an overview of iron metabolism including absorption by enterocytes and regulation of iron by macrophages, liver sinusoidal endothelial cells (LSECs) and hepatocyte production of hepcidin is presented. Hereditary Hemochromatosis and the current pathogenetic model are analyzed. Finally, a new hypothesis based on published data was suggested. The Kupffer cell is the primary defect in HFE hemochromatosis (and possibly in types 2 and 3), while the hepcidin-relative deficiency, which is the common underlying abnormality in the three types of HH, is a secondary consequence.

A decade of iron overload disorders and hemochromatosis: clinical and genetic findings from a specialized center in Colombia

Background

Iron overload disorders, including hereditary hemochromatosis (HH), are characterized by excessive iron accumulation, which can cause severe organ damage. HH is most associated with the C282Y mutation in Caucasian populations, but its prevalence and genetic profiles in Latin American populations remain underexplored.

Objectives

To describe the clinical manifestations, genetic profiles, and biochemical characteristics of patients with suspected iron overload disorders in a specialized hematology center in Cali, Colombia.

Methods

A retrospective observational study was conducted on 70 patients diagnosed with iron overload disorders between 2014 and 2024. Data on clinical presentation, laboratory results, imaging, and genetic mutations were collected. Statistical analyses, including chi-square tests and logistic regression, were used to evaluate factors associated with HH diagnosis.

Results

Male patients constituted 64.3% of the sample, with a mean age of 56.1 years at diagnosis. Fatigue (27.1%) and joint pain (17.1%) were the most common symptoms. Of the total sample, 32.9% were diagnosed with hemochromatosis. The H63D mutation was the most prevalent (52.2%), while the C282Y mutation was rare. A predominance of both slight (100.0%) and limitrophe (58.3%) iron overload was identified among patients with hemochromatosis (p = 0.036).

Conclusion

Colombian patients with iron overload disorders show clinical, epidemiological, and biochemical profiles consistent with global patterns, yet exhibit distinct genetic diversity. Notably, they have a low prevalence of the C282Y mutation and a higher prevalence of the H63D mutation, differing from European HH profiles. Despite elevated ferritin and transferrin saturation, no significant clinical symptoms were observed, suggesting potential delays in diagnosis. These findings highlight the need for early, region-specific diagnostic approaches to prevent complications like cirrhosis and underscore the importance of further genetic research across Latin America.

Iron-Status Indicators and HFE Gene Polymorphisms in Individuals with Amyotrophic Lateral Sclerosis: An Umbrella Review of Meta-analyses and Systematic Reviews

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of motor neurons. Recent meta-analyses and systematic reviews suggest that HFE gene polymorphisms and iron-associated biomarkers may play a key role in the risk and occurrence of ALS. This umbrella study aimed to explore the roles of HFE gene polymorphisms and iron-associated biomarkers in individuals with ALS. A thorough search of three online scientific databases, namely Scopus, Web of Science, and PubMed, was conducted from their inception until September 13, 2024. The screening and selection processes were executed based on the PICO framework and eligibility criteria, followed by two independent reviewers. The Assessment of Multiple Systematic Reviews (AMSTAR)-2 and GRADE tools were utilized to assess the methodological quality and the certainty of evidence. Through an advanced search, 101 records were retrieved, of which eight meta-analyses and systematic reviews were selected for this umbrella review. A significant increase in iron concentrations was found in individuals with ALS compared to healthy controls (SMD, 0.26; 95% CI - 0.05, 0.57). Conversely, selected meta-analyses reported that serum transferrin concentrations in ALS patients were lower compared to healthy controls (SMD, - 0.15; 95% CI - 0.36, 0.05). Furthermore, mutations in H63D polymorphisms resulted in a 13% significant increase in the risk of ALS (OR, 1.13; 95% CI 1.05, 1.22). Our umbrella study of meta-analyses and systematic reviews reveals that individuals with ALS have lower serum concentrations of transferrin compared to healthy controls. Additionally, the H63D polymorphism in the HFE gene is associated with a slight increase in the risk of ALS. Future research should investigate broader aspects of iron-related biomarkers and HFE genes to elucidate their roles in ALS pathogenesis. Registration: Our umbrella study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the identification number CRD42024559032 ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024559032 ).

A common variant in the iron regulatory gene (Hfe) alters the metabolic and transcriptional landscape in brain regions vulnerable to neurodegeneration

The role of iron dyshomeostasis in neurodegenerative disease has implicated the involvement of genes that regulate brain iron. The homeostatic iron regulatory gene (HFE) has been at the forefront of these studies given the role of the H63D variant (H67D in mice) in increasing brain iron load. Despite iron's role in oxidative stress production, H67D mice have shown robust protection against neurotoxins and improved recovery from intracerebral hemorrhage. Previous data support the notion that H67D mice adapt to the increased brain iron concentrations and hence develop a neuroprotective environment. This adaptation is particularly evident in the lumbar spinal cord (LSC) and ventral midbrain (VM), both relevant to neurodegeneration. We studied C57BL6/129 mice with homozygous H67D compared to WT HFE. Immunohistochemistry was used to analyze dopaminergic (in the VM) and motor (in the LSC) neuron population maturation in the first 3 months. Immunoblotting was used to measure protein carbonyl content and the expression of oxidative phosphorylation complexes. Seahorse assay was used to analyze metabolism of mitochondria isolated from the LSC and VM. Finally, a Nanostring transcriptomic analysis of genes relevant to neurodegeneration within these regions was performed. Compared to WT mice, we found no difference in the viability of motor neurons in the LSC, but the dopaminergic neurons in H67D mice experienced significant decline before 3 months of age. Both regions in H67D mice had alterations in oxidative phosphorylation complex expression indicative of stress adaptation. Mitochondria from both regions of H67D mice demonstrated metabolic differences compared to WT. Transcriptional differences in these regions of H67D mice were related to cell structure and adhesion as well as cell signaling. Overall, we found that the LSC and VM undergo significant and distinct metabolic and transcriptional changes in adaptation to iron-related stress induced by the H67D HFE gene variant.

Clinical characteristics of HFE C282Y/H63D compound heterozygotes identified in a specialty practice: key differences from HFE C282Y homozygotes

BACKGROUND

Patients with p.C282Y homozygous (p.C282Y) HFE mutations are more likely to develop hemochromatosis (HC) than p.C282Y/p.H63D compound heterozygotes (p.C282Y/H63D).

RESEARCH DESIGN AND METHODS

We conducted a retrospective chart review of 90 p.C282Y and 31 p.C282Y/H63D patients at a referral practice to illustrate the differences in the natural history of the disease in these two HC cohorts.

RESULTS

Over a median follow-up of 17 years, p.C282Y had higher mean serum ferritin (1105 mg/dL vs. 534 mg/dL, p = 0.001) and transferrin saturations (75.3% vs. 49.5%, p = 0.001) at diagnosis. p.C282Y underwent more therapeutic phlebotomies (TP) till de-ironing (mean 24 vs. 10), had higher mean mobilized iron stores (4759 mg vs. 1932 mg), and required more annual maintenance TP (1.9/year vs. 1.1/year, p = 0.039). p.C282Y/H63D were more likely to have obesity (45.2% vs. 20.2%, p = 0.007) at diagnosis, with a non-significant trend toward consuming more alcohol. There was no significant difference in the development of HC-related complications between the two cohorts.

CONCLUSIONS

p.C282Y have a higher mobilizable iron and require more TP. p.C282Y/H63D likely require additional insults such as obesity or alcohol use to develop elevated ferritin. De-ironing may mitigate the risk of developing HC-related complications.

Drug-Resistant Parkinson's Disease in a Patient With Hereditary Hemochromatosis: A Case Report

A 55-year-old male, with a strong family history of hereditary hemochromatosis, presented with progressively worsening right-sided tremor and Parkinsonian symptoms. He was diagnosed with hereditary hemochromatosis based on genetic testing and started undergoing regular phlebotomies to reduce his blood iron levels. Despite extensive trials of different pharmaceutical therapies, including levodopa-carbidopa, his Parkinsonian symptoms were not relieved and continued to worsen. This report serves to highlight the importance of early disease identification and intervention in patients with hereditary hemochromatosis to prevent the development of neurological sequelae, as well as a need for further research into effective therapies in such patients.

Polycystic ovary syndrome and iron overload: biochemical link and underlying mechanisms with potential novel therapeutic avenues

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder in women with components of significant genetic predisposition and possibly multiple, but not yet clearly defined, triggers. This disorder shares several clinical features with hemochromatosis, a genetically defined inheritable disorder of iron overload, which includes insulin resistance, increased adiposity, diabetes, fatty liver, infertility, and hyperandrogenism. A notable difference between the two disorders, however, is that the clinical symptoms in PCOS appear at much younger age whereas they become evident in hemochromatosis at a much later age. Nonetheless, noticeable accumulation of excess iron in the body is a common finding in both disorders even at adolescence. Hepcidin, the iron-regulatory hormone secreted by the liver, is reduced in both disorders and consequently increases intestinal iron absorption. Recent studies have shown that gut bacteria play a critical role in the control of iron absorption in the intestine. As dysbiosis is a common finding between PCOS and hemochromatosis, changes in bacterial composition in the gut may represent another cause for iron overload in both diseases via increased iron absorption. This raises the possibility that strategies to prevent accumulation of excess iron with iron chelators and/or probiotics may have therapeutic potential in the management of polycystic ovary syndrome.

Risk of Hepatocellular Carcinoma in Patients with Various HFE Genotypes

BACKGROUND AND AIMS

Hereditary hemochromatosis (HH) is associated with increased risk of hepatocellular carcinoma (HCC). However, HCC risk factors within this population and across various HFE genotypes remain unclear.

METHODS

We conducted a retrospective cohort study of patients with ≥ 1 HFE genotype test in the Veterans Health Administration. We followed patients until HCC, death, or 6/30/19. We calculated incidence rates (IRs) and used Cox proportional hazards models to estimate HCC risk. In patients with type-1 HH genotypes (C282Y/C282Y or C282Y/H63D), we examined risk factors for HCC.

RESULTS

We identified 5225 patients: 260 were C282Y/C282Y; 227 were C282Y/H63D; 436 were H63D heterozygous; 535 had other HFE mutations; 3767 without mutation. IR for C282Y/C282Y homozygotes (5.59/1000 PYs) and C282Y/H63D compound heterozygotes (4.12/1000 PYs) were significantly higher than controls (0.92/1000 PYs) with adjusted hazard ratio (adj HR), 95% CI 8.80, 4.17-18.54; and 5.25, 2.24-12.32, respectively. HCC risk was higher in H63D heterozygote than controls (adj HR = 2.82, 95% CI 1.21-6.58); cases were related to non-alcoholic fatty liver disease. Among patients with HH, age ≥ 65 (adj HR = 2.2, 95% CI 0.47-10.27), diabetes (adj HR 3.74, 95% CI 1.25-11.20) and high baseline aspartate-aminotransferase to platelet ratio-index (APRI, adj HR = 3.91, 95% CI 1.29-11.89) had higher risk. Among patients with high baseline ferritin, persistent ferritin > 250 ng/mL had higher risk.

CONCLUSION

HCC risk was high in C282Y homozygous and C282Y/H63D patients. These HFE genotypes, older age, diabetes, high APRI/ferritin levels were associated with increased risk. While H63D heterozygous genotype was associated with HCC risk, this association might be due to metabolic factors.

Twenty-Five Years of Contemplating Genotype-Based Hereditary Hemochromatosis Population Screening

Hereditary hemochromatosis (HH) is a rather frequent, preventable disease because the progressive iron overload affecting many organs can be effectively reduced by phlebotomy. Even before the discovery of the major gene, HFE, in 1996, hemochromatosis was seen as a candidate for population-wide screening programmes. A US Centers of Disease Control and the National Human Genome Research Institute expert panel convened in 1997 to consider genotype-based HH population-wide screening and decided that the scientific evidence available at that time was insufficient and advised against. In spite of a large number of studies performed within the last 25 years, addressing all aspects of HH natural history, health economics, and social acceptability, no professional body worldwide has reverted this decision, and HH remains a life-threatening condition that often goes undetected at a curable stage.

EASL Clinical Practice Guidelines on haemochromatosis

Haemochromatosis is characterised by elevated transferrin saturation (TSAT) and progressive iron loading that mainly affects the liver. Early diagnosis and treatment by phlebotomy can prevent cirrhosis, hepatocellular carcinoma, diabetes, arthropathy and other complications. In patients homozygous for p.Cys282Tyr in HFE, provisional iron overload based on serum iron parameters (TSAT >45% and ferritin >200 μg/L in females and TSAT >50% and ferritin >300 μg/L in males and postmenopausal women) is sufficient to diagnose haemochromatosis. In patients with high TSAT and elevated ferritin but other HFE genotypes, diagnosis requires the presence of hepatic iron overload on MRI or liver biopsy. The stage of liver fibrosis and other end-organ damage should be carefully assessed at diagnosis because they determine disease management. Patients with advanced fibrosis should be included in a screening programme for hepatocellular carcinoma. Treatment targets for phlebotomy are ferritin <50 μg/L during the induction phase and <100 μg/L during the maintenance phase.

Hemochromatosis Gene Mutation in Persons Developing Erythrocytosis on Combined Testosterone and SGLT-2 Inhibitor Therapy

In clinical trials, sodium-glucose cotransporter-2 inhibitors (SGLT-2i) use alone in persons with type 2 diabetes (T2D) or testosterone replacement therapy (TRT) prescription alone in men with hypogonadism was shown to lead to a modest but significant increase in red blood cell mass. Recent evidence indicates that combined use of TRT and SGLT-2i in persons with T2D may be associated with risk of erythrocytosis. However, factor(s) that may lead to the development of erythrocytosis in these patients is unknown. We describe here 5 consecutive patients with hypogonadism on chronic TRT who developed erythrocytosis following addition of SGLT-2i empagliflozin for optimization of T2D management. In addition to the careful review of medical history, all patients underwent genetic screening for hereditary hemochromatosis. We have found that none of the patients had C282Y mutation in the HFE (Homeostatic Iron Regulator) gene and 4 out of 5 patients had heterozygosity in the H63D allele. Upon TRT discontinuation or its dose reduction or referral for scheduled phlebotomy, patients showed resolution of erythrocytosis. Our study reaffirms that practitioners should monitor for changes in hematocrit following the initiation of SGLT-2i in persons with T2D and hypogonadism on chronic TRT. Also, for the first time, we showed that in some of the patients receiving combined TRT and SGLT-2i H63D heterozygosity in the HFE gene may mediate the development of new-onset erythrocytosis.

HFE H63D Limits Nigral Vulnerability to Paraquat in Agricultural Workers

Paraquat is an herbicide whose use is associated with Parkinson's disease (PD), a neurodegenerative disorder marked by neuron loss in the substantia nigra pars compacta (SNc). We recently observed that the murine homolog to the human H63D variant of the homeostatic iron regulator (HFE) may decrease paraquat-associated nigral neurotoxicity in mice. The present study examined the potential influence of H63D on paraquat-associated neurotoxicity in humans. Twenty-eight paraquat-exposed workers were identified from exposure histories and compared with 41 unexposed controls. HFE genotypes, and serum iron and transferrin were measured from blood samples. MRI was used to assess the SNc transverse relaxation rate (R2*), a marker for iron, and diffusion tensor imaging scalars of fractional anisotropy (FA) and mean diffusivity, markers of microstructural integrity. Twenty-seven subjects (9 exposed and 18 controls) were H63D heterozygous. After adjusting for age and use of other PD-associated pesticides and solvents, serum iron and transferrin were higher in exposed H63D carriers than in unexposed carriers and HFE wildtypes. SNc R2* was lower in exposed H63D carriers than in unexposed carriers, whereas SNc FA was lower in exposed HFE wildtypes than in either unexposed HFE wildtypes or exposed H63D carriers. Serum iron and SNc FA measures correlated positively among exposed, but not unexposed, subjects. These data suggest that H63D heterozygosity is associated with lower neurotoxicity presumptively linked to paraquat. Future studies with larger cohorts are warranted to replicate these findings and examine potential underlying mechanisms, especially given the high prevalence of the H63D allele in humans.

Ethnic Differences in Iron Status

Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.

The Perfect Balance? Managing Heavy Menstrual Bleeding and Dysmenorrhea in a Patient with Hereditary Hemochromatosis and von Willebrand Disease

BACKGROUND

Hereditary hemochromatosis typically presents in adulthood with organ damage secondary to iron overload. In women, menstrual periods are a protective mechanism allowing for monthly loss of iron stores.

CASE

We report the case of a female adolescent whose family history, clinical presentation, and laboratory investigation revealed a diagnosis of hereditary hemochromatosis and von Willebrand disease. For control of heavy menstrual bleeding, menstrual suppression was started with a subsequent increase of her ferritin levels.

SUMMARY AND CONCLUSION

No significant data exist regarding the management of women with hereditary hemochromatosis who require menstrual suppression. This case highlights the difficulty in balancing the need for hormonal menstrual suppression with its effect on treatment choices, monitoring, and managing iron levels.

Frequency of hereditary hemochromatosis gene mutations and their effects on iron overload among beta thalassemia patients of Chennai residents

<abstract> <p>Hereditary Hemochromatosis (HH) is an autosomal recessive disorder of iron metabolism associated with <italic>HFE</italic> gene mutations, characterized by increased iron absorption and accumulation leading to multi-organ damage caused by iron overload toxicity. Beta thalassemia is caused by a mutation in the human beta globin gene. Imbalanced production of globin chain results in beta thalassemia, where the unpaired alpha chains precipitates in red cell precursors leading to ineffective erythropoiesis and reduced RBC survival. Both HH and beta thalassemia condition results in rapid accumulation of iron lead to iron overload in tissues and organs. The study aims to analyze the frequency of <italic>HFE</italic> variants among beta thalassemia cases and their effect on iron overload. The frequency of three <italic>HFE</italic> variants C282Y, H63D, S65C was analyzed by PCR RFLP method among Beta Thalassemia Trait (BTT) (n = 203), Beta Thalassemia Major (BTM) (n = 19) and age and sex-matched control samples (n = 200). The present study furnished allele frequency of H63D variant in BTT, BTM and controls 8.13, 15.8 and 6% respectively. Ten out of 33 heterozygous H63D variants exhibited iron overload with higher ferritin levels indicating <italic>HFE</italic> variant might aggravate the absorption of iron. The C282Y variant was present in heterozygous state in 1 case among beta thalassemia carriers. The C282Y variant was absent among BTM and control cases. S65C <italic>HFE</italic> variant was absent in the present study. Iron overload was completely absent in the control cases among all three <italic>HFE</italic> genotypes. Hence it is inferred from the present investigation, analysis of <italic>HFE</italic> genes and iron status will remarkably help to reason out the probable reason behind the iron status and support in proper management of beta thalassemia cases.</p> </abstract>

Genetic diagnosis history and osteoarticular phenotype of a non-transfusion secondary hemochromatosis

BACKGROUND

It is not easy to identify the cause of various iron overload diseases because the phenotypes overlap. Therefore, it is important to perform genetic testing to determine the genetic background of patients.

AIM

To investigate the genetic background of a patient with hemochromatosis complicated by psoriasis on both lower extremities.

METHODS

Ten years ago, a 61-year-old male presented with iron overload, jaundice, hemolytic anemia and microcytic hypochromic anemia. Computed tomography of the left knee joint showed enlargement of the tibial medullary cavity and thinned bone cortices. Magnetic resonance imaging showed hepatic hemochromatosis, extensive abnormal signals from bone marrow cavities and nodular lesions in the lateral medullary cavity of the upper left lateral tibia. Single photon emission computed tomography showed radial dots of abnormal concentration in the upper end of the left tibia and radial symmetry of abnormal concentrations in joints of the extremities. The patient showed several hot spot mutations of the HFE and G6PD genes detected by next-generation sequencing, but no responsible gene mutation was found. The thalassemia gene was detected by gap-PCR.

RESULTS

The patient was found to carry the -α^4.2 and --^SEA deletion mutations of the globin gene. These two mutations are common causes of Southeast Asian α-thalassemia, but rarely cause severe widespread non-transfusion secondary hemochromatosis osteoarthropathy. The simultaneous presence of an auxiliary superposition effect of a rare missense mutation of the PIEZO1 gene (NM_001142864, c.C4748T, p.A1583V) was considered. Moreover, several rare mutations of the IFIH1, KRT8, POFUT1, FLG, KRT2, and TGM5 genes may be involved in the pathogenesis of psoriasis.

CONCLUSION

The selection of genetic detection methods for hemochromatosis still needs to be based on an in-depth study of the clinical manifestations of the disease.

Higher iron stores and the HFE 187C>G variant delay onset of peripheral neuropathy during combination antiretroviral therapy

OBJECTIVE

People with HIV (PWH) continue to experience sensory neuropathy and neuropathic pain in the combination antiretroviral therapy (cART) era for unclear reasons. This study evaluated the role of iron in a previously reported association of iron-loading hemochromatosis (HFE) gene variants with reduced risk of neuropathy in PWH who received more neurotoxic cART, since an iron-related mechanism also might be relevant to neuropathic symptoms in PWH living in low-resource settings today.

DESIGN

This time-to-event analysis addressed the impact of systemic iron levels on the rapidity of neuropathy onset in PWH who initiated cART.

METHODS

Soluble transferrin receptor (sTFR), the sTFR-ferritin index of iron stores, and high-sensitivity C-reactive protein (hsCRP) levels were determined in stored baseline sera from participants of known HFE genotype from AIDS Clinical Trials Group (ACTG) Study 384, a multicenter randomized clinical trial that evaluated cART strategies. Associations with incident neuropathy were evaluated in proportional-hazards, time-to-event regression models, adjusting for potential confounders.

RESULTS

Of 151 eligible participants with stored serum who were included in the original genetic study, 43 had cART-associated neuropathy; 108 had sufficient serum for analysis, including 30 neuropathy cases. Carriers of HFE variants had higher systemic iron (lower sTFR and sTFR-ferritin index) and lower hsCRP levels than non-carriers (all p<0.05). Higher sTFR or iron stores, the HFE 187C>G variant, and lower baseline hsCRP were associated with significantly delayed neuropathy in self-reported whites (n = 28; all p-values<0.05), independent of age, CD4+ T-cell count, plasma HIV RNA, and cART regimen.

CONCLUSIONS

Higher iron stores, the HFE 187C>G variant, and lower hsCRP predicted delayed onset of neuropathy among self-reported white individuals initating cART. These findings require confirmation but may have implications for cART in HIV+ populations in areas with high endemic iron deficiency, especially those PWH in whom older, more neurotoxic antiretroviral drugs are occasionally still used.

Possible Susceptibility Genes for Intervention against Chemotherapy-Induced Cardiotoxicity

Recent therapeutic advances have significantly improved the short- and long-term survival rates in patients with heart disease and cancer. Survival in cancer patients may, however, be accompanied by disadvantages, namely, increased rates of cardiovascular events. Chemotherapy-related cardiac dysfunction is an important side effect of anticancer therapy. While advances in cancer treatment have increased patient survival, treatments are associated with cardiovascular complications, including heart failure (HF), arrhythmias, cardiac ischemia, valve disease, pericarditis, and fibrosis of the pericardium and myocardium. The molecular mechanisms of cardiotoxicity caused by cancer treatment have not yet been elucidated, and they may be both varied and complex. By identifying the functional genetic variations responsible for this toxicity, we may be able to improve our understanding of the potential mechanisms and pathways of treatment, paving the way for the development of new therapies to target these toxicities. Data from studies on genetic defects and pharmacological interventions have suggested that many molecules, primarily those regulating oxidative stress, inflammation, autophagy, apoptosis, and metabolism, contribute to the pathogenesis of cardiotoxicity induced by cancer treatment. Here, we review the progress of genetic research in illuminating the molecular mechanisms of cancer treatment-mediated cardiotoxicity and provide insights for the research and development of new therapies to treat or even prevent cardiotoxicity in patients undergoing cancer treatment. The current evidence is not clear about the role of pharmacogenomic screening of susceptible genes. Further studies need to done in chemotherapy-induced cardiotoxicity.

Infectious Mononucleosis Causing Acute Liver Failure and Hemolytic Anemia in a Patient with Underlying Hereditary Hemochromatosis

Infectious mononucleosis is a largely benign disease process that occurs secondary to infection with the Epstein-Barr virus. However, it can also present with more serious complications, including auto-immune hemolytic anemia and acute liver failure. Hereditary hemochromatosis is a genetic disorder that leads to organ damage via increased iron uptake and deposition. This case report describes a 25-year-old man who presented with acute liver failure and severe hemolytic anemia. Workup revealed that not only did he have a rare presentation of Epstein-Barr virus-induced acute liver failure and C₃-positive IgG-negative hemolytic anemia, he also had previously undiagnosed hereditary hemochromatosis. This combined presentation of these pathologies presents a unique opportunity to study their interaction and possible synergistic pathophysiology. Furthermore, the evolving understanding of the disease mechanisms behind these disease processes is described.

H63D variant of the homeostatic iron regulator (HFE) gene alters α-synuclein expression, aggregation, and toxicity

Pathological features of Parkinson's disease include the formation of Lewy bodies containing α-synuclein and the accumulation of iron in the substantia nigra. Previous studies have suggested that iron accumulation contributes to the Parkinson's disease pathology through reactive oxygen species production and accelerated α-synuclein aggregation. This study examines the effects of commonly occurring H63D variant of the homeostatic iron regulatory (HFE) gene on α-synuclein pathology in cell culture and animal models. H63D HFE expression in SH-SY5Y cells lowered endogenous α-synuclein levels and significantly decreased pre-formed fibril-induced α-synuclein aggregation. H63D HFE cells were also protected from pre-formed fibril-induced apoptosis. Autophagic flux, a major pathway for α-synuclein clearance, was increased in H63D HFE cells. Expression of REDD1 was elevated and rapamycin treatment was unable to further induce autophagy, indicating mTORC1 inhibition as the main mechanism of autophagy induction. Moreover, siRNA knockdown of REDD1 in H63D HFE cells decreased autophagic flux and increased the sensitivity to PFF-mediated toxicity. While iron chelator (deferiprone) treatment rescued WT HFE cells from pre-formed fibril toxicity, it exacerbated or was unable to rescue H63D HFE cells. In the in vivo pre-formed fibril intracranial injection model, H67D Hfe (mouse homolog of the human H63D HFE variant) C57BL/6J × 129 mice showed less α-synuclein aggregation and less decline in motor function compared to WT Hfe. Collectively, this study suggests that H63D HFE variant modifies α-synuclein pathology through the induction of autophagy and has the potential to impact the pathogenesis and treatment response in Parkinson's disease.

Evaluation of a screening program for iron overload and HFE mutations in 50,493 blood donors

Early detection of individuals with hereditary hemochromatosis (HH) is important to manage iron levels and prevent future organ damage. Although theHFE mutations that cause most cases of HH have been identified, their geographic distribution is highly variable, and their contribution to iron overload is not fully understood. All new registered blood donors at the Sahlgrenska University hospital between 1998 and 2015 were included in the study. Donors with signs of iron overload at baseline and subsequent follow-up testing were recommended genotyping of the HFE gene. Of the 50,493 donors that were included in the study, 950 (1.9%) had signs of iron overload on both test occasions. Of the 840 donors with iron overload that performed HFE genotyping, 117 were homozygous for C282Y, and 97 were compound heterozygotes. The prevalence of C282Y homozygosity was 0.23%. Iron overload screening effectively detects individuals at risk of carrying the C282Y mutation of the HFE gene and enables early treatment to prevent HH complications.

Prevalence and characteristics of anti-HCV positivity and chronic hepatitis C virus infection in HFE p.C282Y homozygotes

INTRODUCTION AND AIM

Observations of hepatitis C virus (HCV) infection in adults with hemochromatosis are limited.

MATERIALS AND METHODS

We determined associations of serum ferritin (SF) with anti-HCV in non-Hispanic white North American adults in a post-screening examination. Cases included p.C282Y homozygotes (regardless of screening transferrin saturation (TS) and SF) and participants (regardless of HFE genotype) with high screening TS/SF. Controls included participants without p.C282Y or p.H63D who had normal screening TS/SF. Participants with elevated alanine aminotransferase underwent anti-HCV testing. We determined prevalence of chronic HCV infection in consecutive Alabama and Ontario referred adults with HFE p.C282Y homozygosity.

RESULTS

In post-screening participants, anti-HCV prevalence was 0.3% [95% CI: 0.02, 2.2] in 294 p.C282Y homozygotes, 9.5% [7.2, 12.3] in 560 Cases without p.C282Y homozygosity, and 0.7% [0.2, 2.3] in 403 Controls. Anti-HCV was detected in 7.2% of 745 participants with and 0.8% of 512 participants without elevated SF (odds ratio 9.9 [3.6, 27.6]; p<0.0001). Chronic HCV infection prevalence in 961 referred patients was 1.0% (10/961) [95% confidence interval (CI): 0.5, 2.0]. Ten patients with chronic HCV infection had median age 45y (range 29-67) and median SF 1163μg/L (range 303-2001). Five of eight (62.5%) patients had biopsy-proven cirrhosis.

CONCLUSIONS

Odds ratio of anti-HCV was increased in post-screening participants with elevated SF. Prevalence of anti-HCV in post-screening participants with HFE p.C282Y homozygosity and chronic HCV infection in referred adults with HFE p.C282Y homozygosity in North America is similar to that of Control participants with HFE wt/wt and normal screening TS/SF.

Impact of HFE variants and sex in lung cancer

The homeostatic iron regulator protein HFE is involved in regulation of iron acquisition for cells. The prevalence of two common HFE gene variants (H63D, C282Y) has been studied in many cancer types; however, the impact of HFE variants, sex and HFE gene expression in lung cancer has not been studied. We determined the prevalence of HFE variants and their impact on cancer phenotypes in lung cancer cell lines, in lung cancer patient specimens, and using The Cancer Genome Atlas (TCGA) database. We found that seven out of ten human lung cancer cell lines carry the H63D or C282Y HFE variant. Analysis of lung cancer specimens from our institute (Penn State Hershey Medical Center) revealed a sex and genotype interaction risk for metastasis in lung adenocarcinoma (LUAD) patients; H63D HFE is associated with less metastasis in males compared to wild type (WT) HFE; however, females with the H63D HFE variant tend to develop more metastatic tumors than WT female patients. In the TCGA LUAD dataset, the H63D HFE variant was associated with poorer survival in females compared to females with WT HFE. The frequency of C282Y HFE is higher in female lung squamous cell carcinoma (LUSC) patients of TCGA than males, however the C282Y HFE variant did not impact the survival of LUSC patients. In the TCGA LUSC dataset, C282Y HFE patients (especially females) had poorer survival than WT HFE patients. HFE expression level was not affected by HFE genotype status and did not impact patient's survival, regardless of sex. In summary, these data suggest that there is a sexually dimorphic effect of HFE polymorphisms in the survival and metastatic disease in lung cancer.

ACG Clinical Guideline: Hereditary Hemochromatosis

Hereditary hemochromatosis (HH) is one of the most common genetic disorders among persons of northern European descent. There have been recent advances in the diagnosis, management, and treatment of HH. The availability of molecular diagnostic testing for HH has made possible confirmation of the diagnosis for most patients. Several genotype-phenotype correlation studies have clarified the differences in clinical features between patients with the C282Y homozygous genotypes and other HFE mutation patterns. The increasing use of noninvasive tests such as MRI T2* has made quantification of hepatic iron deposition easier and eliminated the need for liver biopsy in most patients. Serum ferritin of <1,000 ng/mL at diagnosis remains an important diagnostic test to identify patients with a low risk of advanced hepatic fibrosis and should be used routinely as part of the initial diagnostic evaluation. Genetic testing for other types of HH is available but is expensive and generally not useful in most clinical settings. Serum ferritin may be elevated among patients with nonalcoholic fatty liver disease and in those with alcoholic liver disease. These diagnoses are more common than HH among patients with elevated serum ferritin who are not C282Y homozygotes or C282Y/H63D compound heterozygotes. A secondary cause for liver disease should be excluded among patients with suspected iron overload who are not C282Y homozygotes. Phlebotomy remains the mainstay of therapy, but emerging novel therapies such as new chelating agents may have a role for selected patients.

Hereditary Hemochromatosis Associations with Frailty, Sarcopenia and Chronic Pain: Evidence from 200,975 Older UK Biobank Participants

BACKGROUND

Iron is essential for life but contributes to oxidative damage. In Northern-European ancestry populations, HFE gene C282Y mutations are relatively common (0.3%-0.6% rare homozygote prevalence) and associated with excessive iron absorption, fatigue, diabetes, arthritis, and liver disease, especially in men. Iron excess can be prevented or treated but diagnosis is often delayed or missed. Data on sarcopenia, pain, and frailty are scarce.

METHODS

Using 200,975 UK Biobank volunteers aged 60-70 years, we tested associations between C282Y homozygosity with Fried frailty, sarcopenia, and chronic pain using logistic regression adjusted for age and technical genetic covariates. As iron overload is progressive (with menstruation protective), we included specific analyses of older (65-70 years) females and males.

RESULTS

One thousand three hundred and twelve (0.65%) participants were C282Y homozygotes; 593 were men (0.62%) and 719 were women (0.68%). C282Y homozygote men had increased likelihoods of reporting chronic pain (odds ratio [OR] 1.23: 95% confidence interval [CI] 1.05-1.45, p = .01) and diagnoses of polymyalgia rheumatica, compared to common "wild-type" genotype. They were also more likely to have sarcopenia (OR 2.38: 1.80-3.13, p = 9.70 × 10-10) and frailty (OR 2.01: 1.45-2.80, p = 3.41 × 10-05). C282Y homozygote women (n = 312, 0.7%) aged 65-70 were more likely to be frail (OR 1.73: 1.05-2.84, p = .032) and have chronic knee, hip, and back pain. Overall, 1.50% of frail men and 1.51% of frail women in the 65-70 age group were C282Y homozygous.

CONCLUSIONS

HFE C282Y homozygosity is associated with substantial excess sarcopenia, frailty, and chronic pain at older ages. Given the availability of treatment, hereditary hemochromatosis is a strong candidate for precision medicine approaches to improve outcomes in late life.

Common conditions associated with hereditary haemochromatosis genetic variants: cohort study in UK Biobank

OBJECTIVE

To compare prevalent and incident morbidity and mortality between those with the HFE p.C282Y genetic variant (responsible for most hereditary haemochromatosis type 1) and those with no p.C282Y mutations, in a large UK community sample of European descent.

DESIGN

Cohort study.

SETTING

22 centres across England, Scotland, and Wales in UK Biobank (2006-10).

PARTICIPANTS

451 243 volunteers of European descent aged 40 to 70 years, with a mean follow-up of seven years (maximum 9.4 years) through hospital inpatient diagnoses and death certification.

MAIN OUTCOME MEASURE

Odds ratios and Cox hazard ratios of disease rates between participants with and without the haemochromatosis mutations, adjusted for age, genotyping array type, and genetic principal components. The sexes were analysed separately as morbidity due to iron excess occurs later in women.

RESULTS

Of 2890 participants homozygous for p.C282Y (0.6%, or 1 in 156), haemochromatosis was diagnosed in 21.7% (95% confidence interval 19.5% to 24.1%, 281/1294) of men and 9.8% (8.4% to 11.2%, 156/1596) of women by end of follow-up. p.C282Y homozygous men aged 40 to 70 had a higher prevalence of diagnosed haemochromatosis (odds ratio 411.1, 95% confidence interval 299.0 to 565.3, P<0.001), liver disease (4.30, 2.97 to 6.18, P<0.001), rheumatoid arthritis (2.23, 1.51 to 3.31, P<0.001), osteoarthritis (2.01, 1.71 to 2.36, P<0.001), and diabetes mellitus (1.53, 1.16 to 1.98, P=0.002), versus no p.C282Y mutations (n=175 539). During the seven year follow-up, 15.7% of homozygous men developed at least one incident associated condition versus 5.0% (P<0.001) with no p.C282Y mutations (women 10.1% v 3.4%, P<0.001). Haemochromatosis diagnoses were more common in p.C282Y/p.H63D heterozygotes, but excess morbidity was modest.

CONCLUSIONS

In a large community sample, HFE p.C282Y homozygosity was associated with substantial prevalent and incident clinically diagnosed morbidity in both men and women. As p.C282Y associated iron overload is preventable and treatable if intervention starts early, these findings justify re-examination of options for expanded early case ascertainment and screening.

HFE H63D Polymorphism and the Risk for Systemic Hypertension, Myocardial Remodeling, and Adverse Cardiovascular Events in the ARIC Study

H63D has been identified as a novel locus associated with the development of hypertension. The quantitative risks for hypertension, cardiac remodeling, and adverse events are not well studied. We analyzed white participants from the ARIC study (Atherosclerosis Risk in Communities) with H63D genotyping (N=10 902). We related genotype status to prevalence of hypertension at each of 5 study visits and risk for adverse cardiovascular events. Among visit 5 participants (N=4507), we related genotype status to echocardiographic features. Frequencies of wild type (WT)/WT, H63D/WT, and H63D/H63D were 73%, 24.6%, and 2.4%. The average age at baseline was 54.9±5.7 years and 47% were men. Participants carrying the H63D variant had higher systolic blood pressure ( P=0.004), diastolic blood pressure (0.012), and more frequently had hypertension ( P<0.001). Compared with WT/WT, H63D/WT and H63D/H63D participants had a 2% to 4% and 4% to 7% absolute increase in hypertension risk at each visit, respectively. The population attributable risk of H63D for hypertension among individuals aged 45 to 64 was 3.2% (95% CI, 1.3-5.1%) and 1.3% (95% CI, 0.0-2.4%) among individuals >65 years. After 25 years of follow-up, there was no relationship between genotype status and any outcome ( P>0.05). H63D/WT and H63D/H63D genotypes were associated with small differences in cardiac remodeling. In conclusion, the HFE H63D variant confers an increased risk for hypertension per allele and, given its frequency, accounts for a significant number of cases of hypertension. However, there was no increased risk for adverse cardiovascular events or substantial left ventricular remodeling.

Iron-processing genotypes, nutrient intakes, and cadmium levels in the Normative Aging Study: Evidence of sensitive subpopulations in cadmium risk assessment

BACKGROUND

Because iron and cadmium share common transport mechanisms, iron-processing protein variants such as HFE C282Y, HFE H63D, and Transferrin P570S may influence cadmium metabolism. Our aim was to evaluate associations between common HFE and Transferrin polymorphisms and toenail cadmium levels among older men.

METHODS

In a longitudinal cohort of men age 51-97, the Normative Aging Study (NAS), we evaluated toenail cadmium concentrations and missense single nucleotide polymorphisms (SNPs) in the HFE and Transferrin genes. We fit age-adjusted models to estimate associations between genotypes and toenail cadmium concentrations. We then considered potential interactions with smoking status, hemoglobin, and nutritional intakes known to modulate cadmium absorption. For the significant interactions, we also evaluated genotype specific effect estimates.

RESULTS

HFE and Transferrin genotypes were not associated with toenail cadmium concentrations in the main effect analyses, but there were significant interactions between HFE H63D and hemoglobin (p_interaction = 0.021), as well as HFE H63D and vitamin C intake (p_interaction = 0.048). Genotype specific effect estimates suggested: 1) an inverse relationship between hemoglobin and cadmium levels among HFE H63D homozygotes, and 2) an inverse relationship between vitamin C intake and cadmium levels that strengthens with the number of HFE H63D variant alleles a subject carries.

CONCLUSIONS

These findings suggest that sensitive subpopulations defined by diet, hemoglobin level, and genotype may absorb more cadmium from their environment and thus should be considered in cadmium risk analyses. These findings are particularly relevant given the high prevalence of the H63D variant worldwide.

Myeloperoxidase deficiency attenuates systemic and dietary iron-induced adverse effects

Iron deficiency is routinely treated with oral or systemic iron supplements, which are highly reactive and could induce oxidative stress via augmenting the activity of proinflammatory enzyme myeloperoxidase (MPO). To investigate the extent to which MPO is involved in iron-induced toxicity, acute (24 h) iron toxicity was induced by intraperitoneal administration of FeSO₄ (25 mg/kg body weight) to MPO-deficient (MpoKO) mice and their wild-type (WT) littermates. Acute iron toxicity was also assessed in WT mice pretreated with an MPO inhibitor, 4-aminobenzoic acid hydrazide. Systemic iron administration up-regulated circulating MPO and neutrophil elastase and elevated systemic inflammatory and organ damage markers in WT mice. However, genetic deletion of MPO or its inhibition significantly reduced iron-induced organ damage and systemic inflammatory responses. In contrast to the acute model, 8 weeks of 2% carbonyl iron diet feeding to WT mice did not change the levels of circulating MPO and neutrophil elastase but promoted their accumulation in the liver. Even though both MpoKO and WT mice displayed similar levels of diet-induced hyperferremia, MpoKO mice showed significantly reduced inflammatory response and oxidative stress than the WT mice. In addition, WT bone-marrow-derived neutrophils (BMDN) generated more reactive oxygen species than MPO-deficient BMDN upon iron stimulation. Altogether, genetic deficiency or pharmacologic inhibition of MPO substantially attenuated acute and chronic iron-induced toxicity. Our results suggest that targeting MPO during iron supplementation is a promising approach to reduce iron-induced toxicity/side effects in vulnerable population.

A Comparison of Whole Genome Sequencing to Multigene Panel Testing in Hypertrophic Cardiomyopathy Patients

BACKGROUND

As DNA sequencing costs decline, genetic testing options have expanded. Whole exome sequencing and whole genome sequencing (WGS) are entering clinical use, posing questions about their incremental value compared with disease-specific multigene panels that have been the cornerstone of genetic testing.

METHODS AND RESULTS

Forty-one patients with hypertrophic cardiomyopathy who had undergone targeted hypertrophic cardiomyopathy genetic testing (either multigene panel or familial variant test) were recruited into the MedSeq Project, a clinical trial of WGS. Results from panel genetic testing and WGS were compared. In 20 of 41 participants, panel genetic testing identified variants classified as pathogenic, likely pathogenic, or uncertain significance. WGS identified 19 of these 20 variants, but the variant detection algorithm missed a pathogenic 18 bp duplication in myosin binding protein C (MYBPC3) because of low coverage. In 3 individuals, WGS identified variants in genes implicated in cardiomyopathy but not included in prior panel testing: a pathogenic protein tyrosine phosphatase, non-receptor type 11 (PTPN11) variant and variants of uncertain significance in integrin-linked kinase (ILK) and filamin-C (FLNC). WGS also identified 84 secondary findings (mean=2 per person, range=0-6), which mostly defined carrier status for recessive conditions.

CONCLUSIONS

WGS detected nearly all variants identified on panel testing, provided 1 new diagnostic finding, and allowed interrogation of posited disease genes. Several variants of uncertain clinical use and numerous secondary genetic findings were also identified. Whereas panel testing and WGS provided similar diagnostic yield, WGS offers the advantage of reanalysis over time to incorporate advances in knowledge, but requires expertise in genomic interpretation to appropriately incorporate WGS into clinical care.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01736566.

The Role of Diagnosis and Treatment of Underlying Liver Disease for the Prognosis of Primary Liver Cancer

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Underlying chronic liver disease has been associated with an increased risk of developing HCC. This study is a review of the current literature regarding the diagnosis, prognostic significance, and role of treating underlying liver disease in patients who are at risk of primary liver cancer. Relevant peer review of the English literature between 1980 and 2017 within PubMed and the Cochrane library was conducted for scientific content on current advances in managing chronic liver diseases and the development of hepatocellular carcinoma. Hepatitis C virus, hepatitis B virus (HBV), nonalcoholic steatohepatitis, autoimmune hepatitis, hereditary hemochromatosis, Wilson disease, primary biliary cirrhosis, α 1-antitrypsin deficiency, and certain drugs lead to an increased risk of developing HCC. Patients with underlying liver disease have an increased incidence of HCC. Hepatitis C virus, HBV, and hemochromatosis can directly lead to HCC without the presence of cirrhosis, while HCC related to other underlying liver diseases occurs in patients with cirrhosis. Treating the underlying liver disease and reducing the progression to cirrhosis should lead to a decreased incidence of HCC.

HFE Genotype Restricts the Response to Paraquat in a Mouse Model of Neurotoxicity

Parkinson's disease is marked clinically by motor dysfunction and pathologically by dopaminergic cell loss in the substantia nigra and iron accumulation in the substantia nigra. The driver underlying iron accumulation remains unknown and could be genetic or environmental. The HFE protein is critical for the regulation of cellular iron uptake. Mutations within this protein are associated with increased iron accumulation including in the brain. We have focused on the commonly occurring H63D variant of the HFE gene as a disease modifier in a number of neurodegenerative diseases. To investigate the role of H63D HFE genotype, we generated a mouse model in which the wild-type (WT) HFE gene is replaced by the H67D gene variant (mouse homolog of the human H63D gene variant). Using paraquat toxicity as the model for Parkinson's disease, we found that WT mice responded as expected with significantly greater motor function, loss of tyrosine hydroxylase staining and increase microglial staining in the substantia nigra, and an increase in R2 relaxation rate within the substantia nigra of the paraquat-treated mice compared to their saline-treated counterparts. In contrast, the H67D mice showed a remarkable resistance to paraquat treatment; specifically differing from the WT mice with no changes in motor function or changes in R2 relaxation rates following paraquat exposure. At baseline, there were differences between the H67D HFE mice and WT mice in gut microbiome profile and increased L-ferritin staining in the substantia nigra that could account for the resistance to paraquat. Of particular note, the H67D HFE mice regardless of whether or not they were treated with paraquat had significantly less tyrosine hydroxylase immunostaining than WT. Our results clearly demonstrate that the HFE genotype impacts the expression of tyrosine hydroxylase in the substantia nigra, the gut microbiome and the response to paraquat providing additional support that the HFE genotype is a disease modifier for Parkinson's disease. Moreover, the finding that the HFE mutant mice are resistant to paraquat may provide a model in which to study resistant mechanisms to neurotoxicants.

Clinical penetrance in hereditary hemochromatosis: estimates of the cumulative incidence of severe liver disease among HFE C282Y homozygotes

Iron overload (hemochromatosis) can cause serious, symptomatic disease that is preventable if detected early and managed appropriately. The leading cause of hemochromatosis in populations of predominantly European ancestry is homozygosity of the C282Y variant in the HFE gene. Screening of adults for iron overload or associated genotypes is controversial, largely because of a belief that severe phenotypes are uncommon, although cascade testing of first-degree relatives of patients is widely endorsed. We contend that severe liver disease (cirrhosis or hepatocellular cancer) is not at all uncommon among older males with hereditary hemochromatosis. Our review of the published data from a variety of empirical sources indicates that roughly 1 in 10 male HFE C282Y homozygotes is likely to develop severe liver disease during his lifetime unless iron overload is detected early and treated. New evidence from a randomized controlled trial of treatment allows for evidence-based management of presymptomatic patients. Although population screening for HFE C282Y homozygosity faces multiple barriers, a potentially effective strategy for increasing the early detection and prevention of clinical iron overload and severe disease is to include HFE C282Y homozygosity in lists of medically actionable gene variants when reporting the results of genome or exome sequencing.

Reassessing the safety concerns of utilizing blood donations from patients with hemochromatosis

Hereditary hemochromatosis (HH) is a genetic disorder of iron metabolism that may lead to iron overload. Clinical penetrance is low, however those afflicted may develop cirrhosis, hepatocellular carcinoma, diabetes mellitus, and cardiomyopathy. Treatment of HH involves regular phlebotomy to reduce the systemic iron burden. In many countries-including the United States-numerous blood centers do not accept donated blood obtained from HH patients during therapeutic phlebotomy and there are inconsistent positions regarding this globally. This refusal of blood is borne out of a few concerns. First, there is a theoretical increase in the infectious risk of these blood products, particularly by siderophilic organisms such as Yersinia enterocolitica. Second, given the increased incidence of hepatitis C infection from nonvoluntary donors in the 1970s, there is a concern that blood units from HH donors may harbor additional risk given the nonvoluntary nature of their presentation. In this review, we examine the existing biological and clinical data concerning infectious risk and summarize clinical experience from centers allowing HH donors, and demonstrate that blood from HH patients is safe and should be allowed into the donor pool. We conclude that there is no convincing evidence to exclude this population from serving as blood donors. (Hepatology 2018;67:1150-1157).

The role of HFE genotype in macrophage phenotype

Background

Iron regulation is essential for cellular energy production. Loss of cellular iron homeostasis has critical implications for both normal function and disease progression. The H63D variant of the HFE gene is the most common gene variant in Caucasians. The resulting mutant protein alters cellular iron homeostasis and is associated with a number of neurological diseases and cancer. In the brain, microglial and infiltrating macrophages are critical to maintaining iron homeostasis and modulating inflammation associated with the pathogenic process in multiple diseases. This study addresses whether HFE genotype affects macrophage function and the implications of these findings for disease processes.

Methods

Bone marrow macrophages were isolated from wildtype and H67D HFE knock-in mice. The H67D gene variant in mice is the human equivalent of the H63D variant. Upon differentiation, the macrophages were used to analyze iron regulatory proteins, cellular iron release, migration, phagocytosis, and cytokine expression.

Results

The results of this study demonstrate that the H67D HFE genotype significantly impacts a number of critical macrophage functions. Specifically, fundamental activities such as proliferation in response to iron exposure, L-ferritin expression in response to iron loading, secretion of BMP6 and cytokines, and migration and phagocytic activity were all found to be impacted by genotype. Furthermore, we demonstrated that exposure to apo-Tf (iron-poor transferrin) can increase the release of iron from macrophages. In normal conditions, 70% of circulating transferrin is unsaturated. Therefore, the ability of apo-Tf to induce iron release could be a major regulatory mechanism for iron release from macrophages.

Conclusions

These studies demonstrate that the HFE genotype impacts fundamental components of macrophage phenotype that could alter their role in degenerative and reparative processes in neurodegenerative disorders.

Iron-related gene variants and brain iron in multiple sclerosis and healthy individuals

Brain iron homeostasis is known to be disturbed in multiple sclerosis (MS), yet little is known about the association of common gene variants linked to iron regulation and pathological tissue changes in the brain. In this study, we investigated the association of genetic determinants linked to iron regulation with deep gray matter (GM) magnetic susceptibility in both healthy controls (HC) and MS patients. Four hundred (400) patients with MS and 150 age- and sex-matched HCs were enrolled and obtained 3 T MRI examination. Three (3) single nucleotide polymorphisms (SNPs) associated with iron regulation were genotyped: two SNPs in the human hereditary hemochromatosis protein gene HFE: rs1800562 (C282Y mutation) and rs1799945 (H63D mutation), as well as the rs1049296 SNP in the transferrin gene (C2 mutation). The effects of disease and genetic status were studied using quantitative susceptibility mapping (QSM) voxel-based analysis (VBA) and region-of-interest (ROI) analysis of the deep GM. The general linear model framework was used to compare groups. Analyses were corrected for age and sex, and adjusted for false discovery rate. We found moderate increases in susceptibility in the right putamen of participants with the C282Y (+ 6.1 ppb) and H63D (+ 6.9 ppb) gene variants vs. non-carriers, as well as a decrease in thalamic susceptibility of progressive MS patients with the C282Y mutation (left: − 5.3 ppb, right: − 6.7 ppb, p < 0.05). Female MS patients had lower susceptibility in the caudate (− 6.0 ppb) and putamen (left: − 3.9 ppb, right: − 4.6 ppb) than men, but only when they had a wild-type allele (p < 0.05). Iron-gene linked increases in putamen susceptibility (in HC and relapsing remitting MS) and decreases in thalamus susceptibility (in progressive MS), coupled with apparent sex interactions, indicate that brain iron in healthy and disease states may be influenced by genetic factors.

•

Magnetic susceptibility and common gene variants linked to iron were investigated.

•

The C282Y and H63D alleles were associated with putamen and thalamus susceptibility changes.

•

Dependent on allele status, men and women differed in deep GM susceptibility in MS.

A Comparison of Whole Genome Sequencing to Multigene Panel Testing in Hypertrophic Cardiomyopathy Patients

BACKGROUND

As DNA sequencing costs decline, genetic testing options have expanded. Whole exome sequencing and whole genome sequencing (WGS) are entering clinical use, posing questions about their incremental value compared with disease-specific multigene panels that have been the cornerstone of genetic testing.

METHODS AND RESULTS

Forty-one patients with hypertrophic cardiomyopathy who had undergone targeted hypertrophic cardiomyopathy genetic testing (either multigene panel or familial variant test) were recruited into the MedSeq Project, a clinical trial of WGS. Results from panel genetic testing and WGS were compared. In 20 of 41 participants, panel genetic testing identified variants classified as pathogenic, likely pathogenic, or uncertain significance. WGS identified 19 of these 20 variants, but the variant detection algorithm missed a pathogenic 18 bp duplication in myosin binding protein C (MYBPC3) because of low coverage. In 3 individuals, WGS identified variants in genes implicated in cardiomyopathy but not included in prior panel testing: a pathogenic protein tyrosine phosphatase, non-receptor type 11 (PTPN11) variant and variants of uncertain significance in integrin-linked kinase (ILK) and filamin-C (FLNC). WGS also identified 84 secondary findings (mean=2 per person, range=0-6), which mostly defined carrier status for recessive conditions.

CONCLUSIONS

WGS detected nearly all variants identified on panel testing, provided 1 new diagnostic finding, and allowed interrogation of posited disease genes. Several variants of uncertain clinical use and numerous secondary genetic findings were also identified. Whereas panel testing and WGS provided similar diagnostic yield, WGS offers the advantage of reanalysis over time to incorporate advances in knowledge, but requires expertise in genomic interpretation to appropriately incorporate WGS into clinical care.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01736566.

Interventions for hereditary haemochromatosis: an attempted network meta-analysis

BACKGROUND

Hereditary haemochromatosis is a genetic disorder related to proteins involved in iron transport, resulting in iron load and deposition of iron in various tissues of the body. This iron overload leads to complications including liver cirrhosis (and related complications such as liver failure and hepatocellular carcinoma), cardiac failure, cardiac arrhythmias, impotence, diabetes, arthritis, and skin pigmentation. Phlebotomy (venesection or 'blood letting') is the currently recommended treatment for hereditary haemochromatosis. The optimal treatment of hereditary haemochromatosis remains controversial.

OBJECTIVES

To assess the comparative benefits and harms of different interventions in the treatment of hereditary haemochromatosis through a network meta-analysis and to generate rankings of the available treatments according to their safety and efficacy. However, we found only one comparison. Therefore, we did not perform the network meta-analysis and we assessed the comparative benefits and harms of different interventions using standard Cochrane methodology.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and randomised clinical trials registers to March 2016 to identify randomised clinical trials on treatments for hereditary haemochromatosis.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) in participants with hereditary haemochromatosis. We excluded trials which included participants who had previously undergone liver transplantation. We considered any of the various interventions compared with each other or with inactive treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We calculated the odds ratio (OR) and rate ratio with 95% confidence intervals (CI) using both fixed-effect and random-effects models with RevMan 5 based on available-participant analysis. We assessed risk of bias according to Cochrane, controlled risk of random errors with Trial Sequential Analysis, and assessed the quality of the evidence using GRADE.

MAIN RESULTS

Three trials with 146 participants met the inclusion criteria of this review. Two parallel group trials with 100 participants provided information on one or more outcomes. The remaining trial was a cross-over trial, with no usable data for analysis. All the trials were at high risk of bias. Overall, all the evidence was of very low quality. All three trials compared erythrocytapheresis (removal of red cells only, instead of whole blood) versus phlebotomy. Two of the trials shared the same first author. The mean or median age in the three trials ranged from 42 to 55 years. None of the trials reported whether the included participants were symptomatic or asymptomatic or a mixture of both. Two trials were conducted in people who were haemochromatosis treatment-naive. The trial that provided most data for this review excluded people with malignancy, heart failure, and serious cardiac arrhythmias. We found no trials assessing iron-chelating agents.Only one of the trials with 38 participants reported no short-term mortality and no serious adverse events at the end of the short-term follow-up (eight months). Two trials reported the proportion of people with adverse events: 10/49 (20.4%) in the erythrocytapheresis group versus 11/51 (21.6%) in the phlebotomy group. One of these two trials provided data on adverse event rates (42.1 events per 100 participants with erythrocytapheresis versus 52.6 events per 100 participants with phlebotomy). There was no evidence of differences in the proportion of people with adverse events and the number of adverse events (serious and non-serious) between the groups (proportion of people with adverse events: OR 0.93, 95% CI 0.36 to 2.43; participants = 100; trials = 2; number of adverse events: rate ratio 0.80, 95% CI 0.32 to 2.03; participants = 38; trial = 1). There was no difference between the groups regarding short-term health-related quality of life (mean difference (MD) 1.00, 95% CI -10.80 to 12.80; participants = 38; trials = 1). This outcome was measured using EQ-VAS (range: 0 to 100 where a higher score indicates better health-related quality of life). None of the trials reported mortality beyond one year, health-related quality of life beyond one year, liver transplantation, decompensated liver disease, cirrhosis, hepatocellular carcinoma, diabetes, or cardiovascular complications during the long-term follow-up.The two trials that provided data for this review were funded by parties with no vested interest in the results; the source of funding of the third trial was not reported.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine whether erythrocytapheresis is beneficial or harmful compared with phlebotomy. Phlebotomy has less equipment requirements and remains the treatment of choice in people with hereditary haemochromatosis who require blood letting in some form. However, it should be noted that there is no evidence from randomised clinical trials that blood letting in any form is beneficial in people with hereditary haemochromatosis. Having said this, a trial including no treatment is unlikely to be conducted. Future trials should compare different frequencies of phlebotomy and erythrocytapheresis versus phlebotomy with and without different iron-chelating agents compared with each other, and with placebo. Such trials should include long-term follow-up of participants (e.g. using national record linkage databases) to determine whether treatments are beneficial or harmful in terms of clinical outcomes such as deaths, health-related quality of life, liver damage and its consequences, heart damage and its consequences, and other outcomes that are of importance to people with hereditary haemochromatosis.

Movement Disorders Associated With Hemochromatosis

BACKGROUND

Hereditary hemochromatosis (HH) is a genetic disorder causing pathological iron deposition and functional impairment of various organs, predominantly the liver. We assessed patients with HH for the presence of movement disorders.

METHODS

We reviewed the charts of 616 patients with HH who attended hemochromatosis clinic at London Health Sciences Centre, London, ON, Canada, from 1988 to 2015.

RESULTS

We found three HH patients with movement disorders, without any other major systemic manifestation. One had parkinsonism, another had chorea, and the third had tremor. All three patients had evidence of iron deposition in the brain, affecting the basal ganglia in the first two, and the dentate nucleus, red nucleus, and substantia nigra in the third patient. In addition to the C282Y homozygous mutation in the HFE gene, two of our patients had non-HFE gene mutations.

CONCLUSION

HH should be considered in the differential diagnosis of movement disorders with pathological brain iron deposition. We report for the first time chorea in a patient with HH. Non-HFE gene mutations may predispose HH patients to iron deposition in the brain.

Dietary Iron and Colorectal Cancer Risk: A Review of Human Population Studies

Iron is an essential micronutrient that is involved in many redox processes and serves as an integral component in various physiological functions. However, excess iron can cause tissue damage through its pro-oxidative effects, potentiating the development of many diseases such as cancer through the generation of reactive oxidative species. The two major forms of iron in the diet are heme and nonheme iron, both of which are found in several different foods. In addition to natural food sources, intake of nonheme iron may also come from fortified foods or in supplement form. This review summarizes the results of human population studies that have examined the role of dietary iron (heme and nonheme), heme iron alone, and iron from supplements in colorectal carcinogenesis.

Electronic health record interventions at the point of care improve documentation of care processes and decrease orders for genetic tests commonly ordered by nongeneticists

OBJECTIVE

To determine whether electronic health record (EHR) tools improve documentation of pre- and postanalytic care processes for genetic tests ordered by nongeneticists.

METHODS

We conducted a nonrandomized, controlled, pre-/postintervention study of EHR point-of-care tools (informational messages and template report) for three genetic tests. Chart review assessed documentation of genetic testing processes of care, with points assigned for each documented item. Multiple linear and logistic regressions assessed factors associated with documentation.

RESULTS

Preimplementation, there were no significant site differences (P > 0.05). Postimplementation, mean documentation scores increased (5.9 (2.1) vs. 5.0 (2.2); P = 0.0001) and records with clinically meaningful documentation increased (score >5: 59 vs. 47%; P = 0.02) at the intervention versus the control site. Pre- and postimplementation, a score >5 was positively associated with abnormal test results (OR = 4.0; 95% CI: 1.8-9.2) and trainee provider (OR = 2.3; 95% CI: 1.2-4.6). Postimplementation, a score >5 was also positively associated with intervention site (OR = 2.3; 95% CI: 1.1-5.1) and specialty clinic (OR = 2.0; 95% CI: 1.1-3.6). There were also significantly fewer tests ordered after implementation (264/100,000 vs. 204/100,000; P = 0.03), with no significant change at the control site (280/100,000 vs. 257/100,000; P = 0.50).

CONCLUSIONS

EHR point-of-care tools improved documentation of genetic testing processes and decreased utilization of genetic tests commonly ordered by nongeneticists.Genet Med 19 1, 112-120.

Clinical Genetic Testing in Gastroenterology

Rapid advances in genetics have led to an increased understanding of the genetic determinants of human disease, including many gastrointestinal (GI) disorders. Coupled with a proliferation of genetic testing services, this has resulted in a clinical landscape where commercially available genetic tests for GI disorders are now widely available. In this review, we discuss the current status of clinical genetic testing for GI illnesses, review the available testing options, and briefly discuss indications for and practical aspects of such testing. Our goal is to familiarize the practicing gastroenterologist with this rapidly changing and important aspect of clinical care.

Association Studies of HFE C282Y and H63D Variants with Oral Cancer Risk and Iron Homeostasis Among Whites and Blacks

Background: Polymorphisms in the hemochromatosis (HFE) gene are associated with excessive iron absorption from the diet, and pro-oxidant effects of iron accumulation are thought to be a risk factor for several types of cancer. Methods: The C282Y (rs1800562) and H63D (rs1799945) polymorphisms were genotyped in 301 oral cancer cases and 437 controls and analyzed in relation to oral cancer risk, and serum iron biomarker levels from a subset of 130 subjects. Results: Individuals with the C282Y allele had lower total iron binding capacity (TIBC) (321.2 ± 37.2 µg/dL vs. 397.7 ± 89.0 µg/dL, p = 0.007) and higher percent transferrin saturation (22.0 ± 8.7 vs. 35.6 ± 22.9, p = 0.023) than wild type individuals. Iron and ferritin levels approached significantly higher levels for the C282Y allele (p = 0.0632 and p = 0.0588, respectively). Conclusions: Iron biomarker levels were elevated by the C282Y allele, but neither (rs1800562) nor (rs1799945) was associated with oral cancer risk in blacks and whites.