C282Y Mutation Research Articles

“Role of HFE gene in coronary artery disease” – A study from India

IntroductionHereditary hemochromatosis (HH) is an autosomal recessive genetic disease of iron regulation associated with iron overload and failure of several organs. Whether mutations in the hemochromatosis (HFE) gene increase cardiovascular disease risk is still undetermined. In the present study, we aimed to analyse the influence of HFE C282Y gene mutation on the risk of development of coronary artery disease (CAD) in the north Indian population. Materials and methodThe study included hundred CAD patients who showed presence of greater than 50% luminal stenosis in at least one major coronary artery in angiography. Genomic DNA was extracted from peripheral blood leukocytes of CAD patients using a DNA extraction kit (Gene Aid, India) following the manufacturer's protocol. The HFE C282Y gene mutation was investigated by AS-PCR. ResultsThe results showed that out of 100 CAD patients 19 patients were positive for HFE C282Y mutation and 81 patients were negative for mutation. We also evaluated HFE C282Y gene mutation frequency in CAD patients with respect to disease severity and we found there was no significant difference of mutation frequency observed with respect to disease severity in CAD patients cohort i e, those with single coronary artery or those with 2/3 coronary arteries involvement. ConclusionThis study concludes that C282Y mutation plays no significant role in coronary artery disease development or its severity. Thus, there is a need to study this mutation in a large cohort of samples so as to elucidate the exact role of C282Y mutation in CAD.

Regression of Fibrosis Stage With Treatment Reduces Long-Term Risk of Liver Cancer in Patients With Hemochromatosis Caused by Mutation in HFE

Fibrosis stage can decrease following treatment in patients with hemochromatosis caused by mutations in the homeostatic iron regulator gene (HFE), but the effects on cirrhosis are not clear. We assessed regression of severe fibrosis and the ensuing risk of liver cancer after treatment. We performed a retrospective analysis of data from 106 patients in France or Australia who were homozygous for the C282Y mutation in HFE with F3 fibrosis (n = 40) or F4 fibrosis (n = 66) at diagnosis and from whom at least 1 liver biopsy was collected during follow up. We collected data from the time of first biopsy and during follow-up period on patient demographics, treatment, smoking habits, alcohol consumption, infection with hepatitis B or C viruses, and other diseases. The median time between first and last liver biopsy was 9.5 years (range, 3.5-15.6 years). We collected results of tests for liver function, markers of iron stores, and platelet levels. Patients were followed for a median 17.6 years (range, 9.8-24.1 years) for development of liver cancer occurrence. At last liver biopsy, 41 patients (38.6%) had fibrosis scores of F2 or less. Liver cancer occurred in 34 patients (52.3%) with F3 or F4 fibrosis at last liver biopsy vs 2 patients (4.8%) with fibrosis scores of F2 or less at last liver biopsy (P < .001). Liver cancer incidences were 32.8 per 1000 person-years (95% CI, 22.7-45.9 per 1000 person-years) in patients with F3 or F4 fibrosis and 2.3 per 1000 person-years (95% CI, 0.2-8.6 per 1000 person-years) in patients with fibrosis scores of F2 or less (P < .001). In multivariate analysis, male sex (hazard ratio [HR], 6.09; 95% CI, 1.21-30.4), age at diagnosis (HR, 1.16; 95% CI, 1.09-1.25), presence of diabetes (HR, 3.07; 95% CI, 1.35-6.97), excess alcohol consumption (HR, 3.1; 95% CI, 1.47-6.35), serum level of ferritin at diagnosis (P < .01), and regression to fibrosis scores of F2 or less (HR, 0.08; 95% CI, 0.01-0.62) were significantly associated with risk of liver cancer. In a retrospective analysis of patients with hemochromatosis caused by the C282Y mutation in HFE, we found that severe liver fibrosis can regress with treatment. In patients with fibrosis regression to a stage F2 or less, the long-term risk for liver cancer is significantly reduced.

1363 A Rare Case of Heterozygous Hemochromatosis Presenting as Recurrent Pancreatitis

INTRODUCTION: Hemochromatosis induced pancreatitis is a relatively rare cause of acute pancreatitis that may complicate further into chronic or recurrent pancreatitis. However, heterozygous hemochromatosis is an exceptionally rare cause of overt disease with only a few cases reported to date. Herein we describe a case of heterozygous hemochromatosis solely presenting as recurrent pancreatitis. CASE DESCRIPTION/METHODS: A 32-year-old female patient with a past medical history of hypertension presented to our emergency department with epigastric pain of one-day duration. Her only medications were labetalol 300 mg and lorazepam 0.5 mg with reported alcohol use of two glasses of wine up to two to three times a week. On arrival, blood pressure was 177/116 mmHg. All vital signs were otherwise within normal limits. Physical examination was significant for mild epigastric and left upper quadrant tenderness. Initial laboratory workup was remarkable for elevated AST at 197 U/L, ALT of 63 U/L, alkaline phosphatase 124 U/L, and total Bilirubin 1.5 µmol/L. Lipase was within normal limits at 69 U/L. Urine toxicology screen was negative. IgG-4 level was within normal limits as well as triglycerides at 67 mg/dL. Magnetic resonance imaging of the abdomen (Figure 1) showed mild hepatomegaly and hepatic steatosis. The pancreas and gallbladder showed no acute changes. Hepatobiliary iminodiacetic acid (HIDA) scan showed a decreased ejection fraction at 6% (Figure 2). Magnetic resonance cholangiopancreatography (Figure 3) showed signs of chronic pancreatitis and a dilated pancreatic duct proximally. Signal characteristics in the spleen and marrow compartment suggested iron deposition leading to a more thorough investigation for hemochromatosis and hence transferrin saturation level returned elevated at 86% and ferritin at 800. She tested heterozygous for the C282Y mutation. The patient was managed conservatively and discharged home with plans for initiation of phlebotomy. The patient's transferrin saturation and ferritin normalized and reported no recurrent episodes of pancreatitis on follow up at 7 months. DISCUSSION: Hemochromatosis is a condition of iron overload and deposition leading to various organ dysfunction. On that spectrum, pancreatitis is considered an extremely rare manifestation, never mention, the sole presenting manifestation of this disease. Clinicians should be cognizant of the variety of medical conditions that can cause pancreatitis and investigate them when clinically indicated.

2380 Liver Cirrhosis of Unknown Etiology With Iron Overload in a Patient Heterozygous for Hereditary Hemochromatosis and Alpha-1 Antitrypsin

INTRODUCTION: Abnormal liver function tests are frequently detected in routine laboratory work. The differential diagnosis is broad and further evaluation is required to identify and treat the underlying cause. We present a patient with abnormal liver function tests who was found to have a unique genetic makeup. CASE DESCRIPTION/METHODS: A 68-year-old female patient presented with jaundice and dark urine for 3 months. Past medical history was significant for paroxysmal atrial fibrillation and nephrolithiasis. Past surgical history and family history were insignificant. Home medications included aspirin and atenolol. She used alcohol socially and denied IV drug use. Review of systems was unremarkable. On physical exam, the patient was diffusely jaundiced and had scleral icterus. Vital signs were within normal limits. Abdominal exam showed a soft, non-tender, and non-distended abdomen without organomegaly. Skin exam was significant for multiple spider angiomas. She had elevated AST of 518 U/L, ALT of 246 U/L, alkaline phosphatase of 185 U/L, total bilirubin of 9.5 mg/dL, and direct bilirubin of 4.5 mg/dL. Workup was negative for viral hepatitis, Wilson’s disease, autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis. She had elevated Ferritin of 3547 ng/mL and iron saturation of 83%. MRI showed features of intrinsic liver disease without a focal mass. Next, upper endoscopy revealed Grade 1 esophageal varices. Subsequent liver biopsy revealed cirrhosis and increased iron stores. The patient underwent genetic testing for hemochromatosis and alpha-1 antitrypsin deficiency. She had a heterozygous C282Y mutation of the HFE gene. In addition, she had a heterozygous PI*MS mutation of SERPINA1 - the gene that codes for alpha-1 antitrypsin. The patient experienced a slow improvement in her abnormal labs over a period of a few months. DISCUSSION: Hereditary hemochromatosis and alpha-1 antitrypsin deficiency are inherited conditions that result in liver damage and eventually liver cirrhosis. Our patient was heterogenous for the HFE gene and developed iron overload on liver biopsy. She was also heterozygous for PI*MS, a less common mutation for SERPINA1 that causes isolated lung disease. Therefore, we can conclude that our patient’s condition was primarily related to iron overload as a result of a mutated HFE gene.

3183 Explanted Liver Confirming Hereditary Hemochromatosis in an African American Male

INTRODUCTION: Hereditary hemochromatosis (HH) is a disorder in which intestinal iron absorption leads to iron overload. It is associated with mutations in the HFE gene. Most commonly seen in Caucasian individuals; however, it is infrequent to see it present in those of African descent. CASE DESCRIPTION/METHODS: A 52-year-old African American male with a history of decompensated alcoholic cirrhosis with ascites, portosystemic encephalopathy (PSE), and non-bleeding esophageal varices presented to hepatology clinic with a MELD score of 16. He quit drinking ten years before the presentation. He was evaluated for a liver transplant, was subsequently deemed a candidate, and placed on the list. As a part of transplant evaluation, an MRI of the abdomen was obtained approximately which showed cirrhotic liver morphology with no hypervascular liver lesions, but the presence of diffuse T2 hypointensity suggestive of iron overload and fibrosis, located in the liver, pancreas and myocardial tissue (Figure 1). A dedicated cardiac MRI with iron protocol was done to confirm findings and give quantification, which showed iron overload with an iron concentration of 1.8 mg/g of dry weight. Serology showed serum iron 125 ug/dL (normal), ferritin 1281 ng/mL (very high), 95% transferrin saturation (very high), and total iron binding capacity of 132 ug/dL (very low). Hereditary hemochromatosis (HH) was suspected, and genetic testing was conducted. The patient was found to be negative for HFE mutations C282Y, H63D, and S65C. Two months following the serological workup, he underwent a liver transplant with an ABO identical allograft liver. The explanted liver (Figure 2) showed severe iron overload in the hepatocytes confirmed by iron stain with pericanalicular accentuation (Figure 3). The diagnosis was confirmed to be HH. DISCUSSION: HH was confirmed when the presence of multi-organ iron overload was seen in imaging, serology showed significant ferritinemia with 95% transferrin saturation, and biopsy showed the presence of severe iron overload in the hepatocytes. While genetic testing for C282Y, H63D, and S65C was negative, this does not mean HH can be ruled out. Identifying these mutations is not necessary for the diagnosis of HH, but the mutations are predominantly positive in Caucasians. For other ethnicities, including Africans, there are rare HH mutations that can return positive but were not tested. This case describes a rare phenomenon of biopsy proven HH found in an African American male.

Hemochromatosis in India: First Report of Whole Exome Sequencing With Review of the Literature

Primary hemochromatosis is unusual in India. The homeostatic iron regulator (HFE) gene C282Y mutation, a common cause for hemochromatosis in Europe, is considered almost nonexistent in India. We are reporting a case of hemochromatosis with the HFE gene C282Y mutation and two other adult cases with a novel hemojuvelin (HJV) mutation from Kerala. Of 434 cases with chronic liver disease, 3 cases were identified with the serum ferritin level of more than 1000ng/mL and primary hemochromatosis after excluding secondary causes. Whole exome sequencing, including genes HFE, HJV, SLC40A1, TFR2, FTH1, HAMP, SKIV2L, TTC37, and BMP2, was performed for blood samples in all 3 cases. One patient with hemochromatosis had a homozygous HFE gene C282Y mutation, and two other adult cases had a novel homozygous HJV D355Y mutation. This is the first report of hemochromatosis associated with the HFE C282Y mutation from Kerala and the second report in India. This is the second report of hemochromatosis associated with an HJV mutation from India. HJV mutations may explain some of the adult onset primary hemochromatosis in India.

Transferrin Saturation Inversely Correlates with Platelet Function.

The association between iron overload (IO) and risk of cardiovascular disease is controversial. Epidemiological studies have found a significant negative association of transferrin (Tf) saturation and cardiovascular events suggesting that higher body iron possibly confer a protective effect towards developing cardiovascular events. The biological mechanisms of this phenomenon are unknown. This article investigates the role of IO on platelet reactivity. This study was a prospective case-control study comparing 45 patients with IO, mostly characterized by the HFE gene mutations C282Y and/or H63D, with 32 healthy controls. We evaluated: (1) platelet aggregation in both platelet-rich plasma and whole blood, (2) platelet membrane expression of the activation marker CD62P, (3) activation of platelet signalling phosphoinositide 3-kinase /Akt and mitogen-activated protein kinase/extracellular signal-regulated kinases (Erk)-1/2 pathways, (4) a pattern of in vivo platelet activation markers, and (5) iron biomarker predictors of platelet reactivity. IO patients had significantly lower platelet aggregability, expression of CD62P and phosphorylation amounts of pAkt and pErk-2 in response to agonists. Furthermore, patients with higher Tf saturation levels were characterized by lower circulating levels of sCD40L, PDGF-BB and thromboxane B2. Platelet aggregation and activation parameters inversely correlated with Tf saturation and the stepwise multivariate regression analysis underlined the role of Tf saturation in predicting platelet reactivity. We also found that in vitro platelet exposure to diferric Tf, but not to iron-depleted TF, dose-dependently inhibited platelet function in all investigated subjects. Tf saturation is inversely associated with platelet reactivity and this could explain, at least in part, the association of high Tf and lower risk of cardiovascular diseases in IO.

Review article: iron disturbances in chronic liver diseases other than haemochromatosis - pathogenic, prognostic, and therapeutic implications.

Disturbances in iron regulation have been described in diverse chronic liver diseases other than hereditary haemochromatosis, and iron toxicity may worsen liver injury and outcome. To describe manifestations and consequences of iron dysregulation in chronic liver diseases apart from hereditary haemochromatosis and to encourage investigations that clarify pathogenic mechanisms, define risk thresholds for iron toxicity, and direct management METHODS: English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Hyperferritinemia is present in 4%-65% of patients with non-alcoholic fatty liver disease, autoimmune hepatitis, chronic viral hepatitis, or alcoholic liver disease, and hepatic iron content is increased in 11%-52%. Heterozygosity for the C282Y mutation is present in 17%-48%, but this has not uniformly distinguished patients with adverse outcomes. An inappropriately low serum hepcidin level has characterised most chronic liver diseases with the exception of non-alcoholic fatty liver disease, and the finding has been associated mainly with suppression of transcriptional activity of the hepcidin gene. Iron overload has been associated with oxidative stress, advanced fibrosis and decreased survival, and promising therapies beyond phlebotomy and oral iron chelation have included hepcidin agonists. Iron dysregulation is common in chronic liver diseases other than hereditary haemochromatosis, and has been associated with liver toxicity and poor prognosis. Further evaluation of iron overload as a co-morbid factor should identify the key pathogenic disturbances, establish the risk threshold for iron toxicity, and promote molecular interventions.

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

BackgroundIron 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.MethodsUsing 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.ResultsOne 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.

Hepcidin is a useful biomarker to evaluate hyperferritinemia associated with metabolic syndrome.

Investigation of hyperferritinemia in metabolic syndrome patients represents a diagnostic challenge, but it is essential for the identification of individuals with iron overload. Hepcidin negatively regulates iron absorption and release. An increase in hepcidin occurs when iron levels are sufficient or in inflammatory states, conditions often associated with hyperferritinemia. Hemochromatosis causes hyperferritinemia due to iron overload, but frequently has low hepcidin levels. Our aim was to evaluate biochemical and molecular parameters related to iron metabolism in patients with metabolic syndrome. We evaluated 94 patients with metabolic syndrome according to the International Diabetes Federation criteria in a cross-sectional study. Anthropometric data and diagnostic criteria for metabolic syndrome, iron dosage, ferritin, transferrin saturation, hepcidin, and the C282Y and H63D mutations in the HFE hemochromatosis gene were evaluated. Prevalence of hyperferritinemia in the study population was 27.7% and was higher in males (46.2%) than in females (14.5%). Increase in transferrin saturation correlated with mutations in the hemochromatosis gene. Hyperferritinemia was associated to transferrin saturation and hepcidin after logistic regression analysis. In conclusion, hyperferritinemia is a frequent finding in metabolic syndrome patients, most frequently in men; and hepcidin assessment can be useful for the investigation of ferritin increase in those subjects.

Polycythemia in Patients With Hereditary Hemochromatosis: Real or Myth?

BackgroundHereditary hemochromatosis (HH) is an autosomal recessive disorder affecting iron metabolism, resulting in iron accumulation in tissue parenchymal cells. Missense mutations result in homozygosity or heterozygosity for substitutions in the HFE gene, with the most common being C282Y and H63D.MethodsWith an aim to evaluate an association between polycythemia and HH, retrospective chart review was performed for 152 patients with known HFE mutations. Parameters reviewed included individual HFE genotypes, gender distribution, hemoglobin (Hgb) and hematocrit (Hct) levels, median ferritin levels and whether or not phlebotomy was required.ResultsOf 152 patients, 96 (63.2%) were men and 56 (36.8%) were women. Median Hgb and Hct were noted to be higher in men compared to women irrespective of HFE status. Mean age was 60.5 years (range 22 - 93 years). Regarding HFE mutation, 44 (28.9%) patients were C282Y/C282Y, 10 (6.6%) were H63D/H63D and 27 (17.8%) had one copy of each mutation. One patient in the study group was H63D/S65C. Median Hgb and Hct were noted to be 15.5 g/dL and 44.9% respectively in C282Y/C282Y subjects, 16.0 g/dL and 47% in H63D/H63D subjects, 15.8 g/dL and 46% in C282Y/H63D subjects, 16g/dL and 47% in those with single C282Y mutation and 16.6g/dL and 48% in those with single H63D mutation. A total of 67.1% subjects received phlebotomy. A total of 21.7% patients in this cohort were active tobacco users and only 8.6% had an established pulmonary diagnosis, including obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD). Elevated Hgb levels were noted despite absence of an established reason for secondary polycythemia. Anemia was not encountered despite concurrent medical conditions that would usually be associated with anemia, including gastrointestinal bleeding or end-stage renal disease (ESRD).ConclusionsElevated Hgb and Hct levels in HH may be secondary to increased iron uptake by erythroid cell precursors in the bone marrow, in setting of increased availability of both transferrin-bound as well as non-transferrin-bound iron (NTBI). Additional studies need to be pursued to explore the association between HFE mutations and secondary polycythemia.

Diagnosis and Treatment of Genetic HFE-Hemochromatosis: The Danish Aspect.

This paper outlines the Danish aspects of HFE-hemochromatosis, which is the most frequent genetic predisposition to iron overload in the five million ethnic Danes; more than 20,000 people are homozygous for the C282Y mutation and more than 500,000 people are compound heterozygous or heterozygous for the HFE-mutations. The disorder has a long preclinical stage with gradually increasing body iron overload and eventually 30% of men will develop clinically overt disease, presenting with symptoms of fatigue, arthralgias, reduced libido, erectile dysfunction, cardiac disease and diabetes. Subsequently the disease may progress into irreversible arthritis, liver cirrhosis, cardiomyopathy, pancreatic fibrosis and osteoporosis. The effective standard treatment is repeated phlebotomies, which in the preclinical and early clinical stages ensures a normal survival rate. Early detection of the genetic predisposition to the disorder is therefore important to reduce the overall burden of clinical disease. Population screening seems to be cost-effective and should be considered.

Kinetics of Iron Depletion in Hereditary Hemochromatosis

Introduction: Hereditary hemochromatosis (HH) is a genetic disorder that results in an increased accumulation of dietary iron. The only effective treatment is iron depletion by phlebotomy or erytrocytapheresis (EA). The kinetics of iron depletion in response to these treatments has been little studied and its temporal profile and the influence of patient's factors are not fully known.Objective: To describe the kinetics of iron depletion in patients with HH on phlebotomy or EA.Material and methods: Patients in depletive treatment with phlebotomy (once per week) or EA (one every two weeks) were selected for this study if they had no associated inflammatory disorder, at least 3 ferritin determinations were available during treatment, and more than 70% of the established therapeutic schedule was fulfilled. The average reduction of serum ferritin was measured in ng/ml per ml of red blood cells (RBC) removed per Kg of patient's body weight, and was analyzed as natural logarithms (ln). Categorical variables were expressed as proportions and continuous variables, as median and interquartile range (IQR).Results: Median age of the 34 included patients was 51 (44-58) years and 32 (94%) were men. Initial and final ferritin values were 1035 (IQR: 777-1564) ng/ml and 83 (IQR: 50-123) ng/ml, respectively. Transaminase levels were high (ALT> 50 U/L) in 9 patients, and 2 of them had been diagnosed with liver cirrhosis secondary to HH. With regard to genotype, 27 patients were C282Y homozygous, 4 were compound heterozygous (C282Y/H63D), 1 had a TFR2 mutation, and no mutation was found in 2. The average reduction of serum ferritin was 1.04 (IQR: 1.03-1.05) ng/mL per mL of removed RBCs/Kg of patient's body weight. Figure 1 shows the mathematical expression that best described the kinetics of serum ferritin.The rate of serum ferritin reduction, as measured by this mathematical expression, was independent of the initial ferritin level, the total reduction of ferritin, the presence of high transaminase levels or cirrhosis, as well as the patient's age and body mass index. In contrast, the rate of ferritin reduction varied with the genotype; it was significantly lower in patients homozygous for the C282Y mutation than in patients with other genotypes (median: 1.03, IQR: 1.02-1.05 vs. 1.07, IQR: 1.06-1.11 ng/mL per mL of removed RBCs/Kg; p < 0.001; figure 2).Conclusions: In patients with HH and good adhesion to the therapeutic schedule, the reduction of serum ferritin is predictable as a function of the volume of removed RBCs and the patient's weight. Patients homozygous for the C282Y mutation have a slower kinetics of iron depletion. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Iron as a Therapeutic Target in HFE-Related Hemochromatosis: Usual and Novel Aspects.

Genetic hemochromatosis is an iron overload disease that is mainly related to the C282Y mutation in the HFE gene. This gene controls the expression of hepcidin, a peptide secreted in plasma by the liver and regulates systemic iron distribution. Homozygous C282Y mutation induces hepcidin deficiency, leading to increased circulating transferrin saturation, and ultimately, iron accumulation in organs such as the liver, pancreas, heart, and bone. Iron in excess may induce or favor the development of complications such as cirrhosis, liver cancer, diabetes, heart failure, hypogonadism, but also complaints such as asthenia and disabling arthritis. Iron depletive treatment mainly consists of venesections that permit the removal of iron contained in red blood cells and the subsequent mobilization of stored iron in order to synthesize hemoglobin for new erythrocytes. It is highly efficient in removing excess iron and preventing most of the complications associated with excess iron in the body. However, this treatment does not target the biological mechanisms involved in the iron metabolism disturbance. New treatments based on the increase of hepcidin levels, by using hepcidin mimetics or inducers, or inhibitors of the iron export activity of ferroportin protein that is the target of hepcidin, if devoid of significant secondary effects, should be useful to better control iron parameters and symptoms, such as arthritis.

Opportunistic Screening for Hereditary Hemochromatosis With Unenhanced CT: Determination of an Optimal Liver Attenuation Threshold.

The purpose of this study was to assess whether a specific liver attenuation threshold for unenhanced CT allows both sensitive opportunistic detection of unsuspected hereditary hemochromatosis and low overall screening test-positive rates. We used a standard ROI placement method on unenhanced CT studies of 3357 consecutive adults (mean age, 57.0 years) with no symptoms of liver disease who underwent colorectal screening. Hepatic attenuation (in HU) was measured to assess test-positive rates at various liver attenuation thresholds. To assess sensitivity, unenhanced hepatic CT attenuation was also measured in 12 patients with hereditary hemochromatosis (mean age, 48.3 years), who were homozygous for the HFE C282Y mutation. All scans were obtained at 120 kV. Serum ferritin levels were recorded for the hereditary hemochromatosis cohort. Mean liver attenuation ± SD among screened adults was 59.4 ± 12.7 HU, compared with 78.7 ± 13.1 HU (range, 59-105 HU) in the hereditary hemochromatosis cohort (p < 0.001). Screening test-positive rates were 30.6% (n = 1028) at 65 HU, 8.2% (n = 275) at 70 HU, 1.2% (n = 39) at 75 HU, and 0.2% (n = 7) at 80 HU. Corresponding sensitivities for hereditary hemochromatosis at these thresholds were 83.3% (10/12) at 65, 70, and 75 HU; and 50.0% (6/12) at 80 HU. Serum ferritin levels were elevated in all patients with hereditary hemochromatosis (mean, 1678 ng/mL; range, 477-3991 ng/mL). An unenhanced CT liver attenuation threshold of 75 HU was sensitive (83.3%) for hereditary hemochromatosis while maintaining an acceptably low screening test-positive rate (1.2%). An unexplained liver attenuation of 75 HU or more on unenhanced CT should trigger appropriate laboratory investigation for iron overload; early intervention with phlebotomy can limit or prevent organ damage in patients with hemochromatosis.

Mutations in the HFE gene can be associated with increased lung disease severity in cystic fibrosis

Background and ObjectiveGenetic modifiers contribute to variable disease phenotype in cystic fibrosis (CF). We explored the association between mutations in the hemochromatosis (HFE) gene and disease severity in adults with CF. MethodsHFE genotyping was performed in 163 adults with CF attending a single centre. Results were correlated with lung disease severity, prevalence of CF-related diabetes (CFRD) and history of meconium ileus (MI) or distal intestinal obstruction syndrome (DIOS). ResultsSubjects with the C282Y substitution in the HFE protein (C282Y mutation) had a lower FEV1 percentage predicted (54% versus 66%, p = 0.029) and accelerated rate of FEV1 decline (−110 mL versus −80 mL per year respectively, p < 0.001) compared to subjects with a normal HFE genotype. C282Y substitutions were associated with increased rates of CFRD (58% versus 33%, p = 0.026) and a trend towards increased MI or DIOS (38% versus 19%, p = 0.05). H63D HFE substitutions were associated with a more rapid rate of decline in forced vital capacity (p = 0.01) and increased risk of MI or DIOS (p = 0.02). ConclusionsIn subjects with CF, the C282Y HFE substitution was associated with worse lung function, and increased rates of CFRD and gastrointestinal complications. The H63D HFE substitution also impacted on disease phenotype, but to a lesser extent. The results support a role for HFE gene mutations as modifiers of CF phenotype.

Multiplex Allele-Specific PCR for Simultaneous Detection of H63D and C282Y HFE Mutations in Hereditary Hemochromatosis.

Hereditary hemochromatosis (HH) is characterized by excessive iron absorption in the intestine, which can lead to failure of vital organs such as the heart, liver, and pancreas. Among northern Europeans, HH is most often associated with the C282Y and H63D mutations of the HFE gene. We developed a test that allows screening for both mutations in a single reaction. A multiplex allele-specific PCR was developed for simultaneous genotyping of the H63D and C282Y HFE mutations. PCR fragments were designed such that the resulting PCR product can be analyzed in a single polyacrylamide gel lane. Test results from our multiplex assay were concordant with genotypes of 55 Canadian patients with suspected hemochromatosis, which had previously been established by allele-specific PCRs that targeted H63D and C282Y in separate reactions. Molecular diagnostic detection of H63D and C282Y mutations can be achieved by a variety of methods, but these are not necessarily time-efficient or economical. Multiplex allele-specific PCR is an excellent tool for molecular diagnostic screening for H63D and C282Y mutations in patients with suspected hemochromatosis. This method is inexpensive, accurate, and highly efficient in terms of labor, throughput, and turnaround time.

Hemochromatisis HFE mutations: Penetrance in 451,000 adults of European descent

Introduction HFE C282Y mutations account for the majority of hereditary hemochromatosis (HH) in people of European descent. HH is characterised by progressive accumulation of iron, plus chronic pain, exhaustion, arthritis, diabetes, liver cirrhosis and liver cancer. Previous studies (mainly in 20- to 50-year-olds) suggested that development of related disease in those with the mutation was uncommon. As a result of the claimed low penetrance, identification of additional cases within families is advised, but screening is not recommended. Methods We estimated C282Y homozygote associations with morbidity and mortality in 40- to 70-year-old UK Biobank volunteers, from England, Scotland and Wales. We included 451,243 subjects of European descent, and tested baseline and incident disease and mortality associations during follow-up (maximum 9.7 years). Follow-up was through hospital records, cancer registry and death certificates. Odds ratios and Cox hazard ratios were adjusted for age, sex and technical covariates. Results There were n = 2890 C282Y homozygote subjects (0.64% of the 451,243 subjects, or 1 in 156). Excess morbidity was most common in older men (age 60 to 70). C282Y homozygous status was associated with increased presence of hemochromatosis, liver disease, diabetes, arthritis, osteoporosis, pneumonia and polymyalgia rheumatica. Overall, 51.8% of older male C282Y homozygotes had ≥ 1 of the associated diagnoses, compared to 28.6% of those with the wild type (common) genotype: odds ratio = 2.63 95% CI: 2.23 to 3.10, P = 3.1 × 10−31. Increased risks for the associated conditions were also present in older women and younger groups but were less common. There was a modest increase in morbidity in heterozygotes. Conclusion We conclude that HFE C282Y homozygosity has a far higher penetrance than previously reported, and is a major contributor to common disease occurrence, especially with advancing age. The case for systematic early identification of iron overload related to HFE mutations needs to be re-examined.

SLC40A1 and CP single nucleotide polymorphisms in porphyria cutanea tarda patients of mixed ancestry.

Porphyria cutanea tarda (PCT) is a multifactorial disease; clinical expression depends on both genetic and acquired factors. Few studies have examined the connection between PCT and the regulation of iron metabolism genes other than the HFE gene. We selected five polymorphisms in the CYBRD1, CP, SLC40A1, and HAMP genes to determine whether these polymorphisms can act as genetic modulators in patients with sporadic PCT. None of the 29 patients carried the C282Y mutation. Genomic DNA from 29 PCT patients was isolated. Alleles were discriminated using the ABI StepOnePlus Real-Time PCR System using TaqMan Assays. The results were compared with 107 healthy individuals matched for genetic ancestry, gender, and age. European ancestry was prevalent among PCT patients (68.3%). The frequency of the TT genotype of rs13015236 in the SLC40A1 gene was higher in PCT patients (44.8%) than in controls (20.6%) (P<0.02). The C allele was more frequent among healthy individuals (53.3%) compared with patients (34.5%) (P<0.01). The rs17838832 G allele of the CP gene was more common among PCT patients (14.3%) compared with controls (4.9%) (P<0.05). There was no statistically significant difference concerning the three remaining polymorphisms. Our data highlight a possible role for the rs17838832 single nucleotide polymorphisms in CP in causing PCT (higher frequency of the G variant in patients). Regarding the rs13015236 single nucleotide polymorphisms in SLC40A1, the presence of a C allele could protect against PCT.

Haemochromatosis.

Haemochromatosis is defined as systemic iron overload of genetic origin, caused by a reduction in the concentration of the iron regulatory hormone hepcidin, or a reduction in hepcidin-ferroportin binding. Hepcidin regulates the activity of ferroportin, which is the only identified cellular iron exporter. The most common form of haemochromatosis is due to homozygous mutations (specifically, the C282Y mutation) in HFE, which encodes hereditary haemochromatosis protein. Non-HFE forms of haemochromatosis due to mutations in HAMP, HJV or TFR2 are much rarer. Mutations in SLC40A1 (also known as FPN1; encoding ferroportin) that prevent hepcidin-ferroportin binding also cause haemochromatosis. Cellular iron excess in HFE and non-HFE forms of haemochromatosis is caused by increased concentrations of plasma iron, which can lead to the accumulation of iron in parenchymal cells, particularly hepatocytes, pancreatic cells and cardiomyocytes. Diagnosis is noninvasive and includes clinical examination, assessment of plasma iron parameters, imaging and genetic testing. The mainstay therapy is phlebotomy, although iron chelation can be used in some patients. Hepcidin supplementation might be an innovative future approach.