HFE hemochromatosis: an overview about therapeutic recommendations

Iron overload is not the same everywhere: Particularities of iron-metabolism gene mutations in Brazil and a proposal for the investigation and management of iron overload in this population

There is no physiological mechanism for the excretion of iron in humans, and excess iron may lead to severe tissue damage if not adequately treated. Iron overload can be caused by genetic factors (hemochromatosis) or acquired conditions (e.g., ineffective erythropoiesis, transfusions, iatrogenic iron treatment, viral hepatitis, alcohol intake, severe liver disease, metabolic dysfunction), and, in many cases, by a conjunction of these factors. Historically, guidelines for the genetic investigation of patients with iron overload have been based on data obtained from Caucasian individuals in Europe and North America. However, due to the genetic heterogeneity of iron overload gene mutations worldwide, these recommendations might not be applicable to other ethnic groups. This study analyzed previously published genetic data obtained from Brazilian patients with iron overload and found a relevant but small prevalence of HFE C282Y/C282Y patients when compared to European populations, while mutations of the TFR2, SCL40A1, HJV, HAMP, BMP6 and SLC11A1 genes seem to be important. This study proposes an adapted algorithm for the investigation and management of iron overload in Brazil.

Impact of body fat composition on liver iron overload severity in hemochromatosis: a retrospective MRI analysis

PURPOSE

To evaluate the correlation between ectopic adipose tissue and iron overload severity in patients with hemochromatosis.

MATERIAL AND METHODS

A retrospective cohort of 52 patients who underwent liver iron concentration quantification from January 2015 to October 2023 using a 3.0T MRI scanner. R2* relaxation times and proton density fat fraction (PDFF) were assessed for the entire liver volume and a specific region of interest (ROI) placed in the right lobe. Total body fat (TF), subcutaneous fat (SCF), intermuscular fat (IMF), and visceral fat (VSF) percentages were calculated from a single axial slice at the level of the third lumbar vertebra. Additionally, ratios of IMF-to-VSF, IMF-to-SCF, and SCF-to-VSF were calculated. Standard iron laboratory parameters were collected at least one month prior to MRI. Pearson correlation coefficient was used for correlation analysis.

RESULTS

The mean age of participants was 53.9 ± 19.6 years. IMF positively correlated with R2* values in the ROI (p = 0.005, rs = 0.382) and entire liver (p = 0.016, rs = 0.332). Conversely, VSF negatively correlated with R2* values from the ROI (p = < 0.001, rs = - 0.488) and entire liver (p = < 0.001, rs = - 0.459). Positive correlations were also found between IMF-to-VSF and R2* of the ROI (p = 0.003, rs = 0.400) and whole liver (p = 0.008, rs = 0.364). Ferritin levels positively correlated with R2* values calculated from ROI (p = 0.002, rs = 0.417) and whole liver volume (p = 0.004, rs = 0.397). A positive correlation was noted between PDFF of the entire liver and TF (p = 0.024, rs = 0.313).

CONCLUSION

The percentage of Intermuscular and visceral adipose tissues correlates with the severity of liver iron overload in hemochromatosis patients.

Hemochromatosis-How Not to Overlook and Properly Manage "Iron People"-A Review

Hemochromatosis (HC) is the main genetic disorder of iron overload and is regarded as metal-related human toxicosis. HC may result from HFE and rare non-HFE gene mutations, causing hepcidin deficiency or, sporadically, hepcidin resistance. This review focuses on HFE-related HC. The illness presents a strong biochemical penetrance, but its prevalence is low. Unfortunately, the majority of patients with HC remain undiagnosed at their disease-curable stage. The main aim of HC management is to prevent iron overload in its early phase and remove excess iron from the body by phlebotomy in its late stage. Raising global awareness of HC among health staff, teaching them how not to overlook early HC manifestations, and paying attention to careful patient monitoring remain critical management strategies for preventing treatment delays, upgrading its efficacy, and improving patient prognosis.

Hemochromatosis: Ferroptosis, ROS, Gut Microbiome, and Clinical Challenges with Alcohol as Confounding Variable

Hemochromatosis represents clinically one of the most important genetic storage diseases of the liver caused by iron overload, which is to be differentiated from hepatic iron overload due to excessive iron release from erythrocytes in patients with genetic hemolytic disorders. This disorder is under recent mechanistic discussion regarding ferroptosis, reactive oxygen species (ROS), the gut microbiome, and alcohol abuse as a risk factor, which are all topics of this review article. Triggered by released intracellular free iron from ferritin via the autophagic process of ferritinophagy, ferroptosis is involved in hemochromatosis as a specific form of iron-dependent regulated cell death. This develops in the course of mitochondrial injury associated with additional iron accumulation, followed by excessive production of ROS and lipid peroxidation. A low fecal iron content during therapeutic iron depletion reduces colonic inflammation and oxidative stress. In clinical terms, iron is an essential trace element required for human health. Humans cannot synthesize iron and must take it up from iron-containing foods and beverages. Under physiological conditions, healthy individuals allow for iron homeostasis by restricting the extent of intestinal iron depending on realistic demand, avoiding uptake of iron in excess. For this condition, the human body has no chance to adequately compensate through removal. In patients with hemochromatosis, the molecular finetuning of intestinal iron uptake is set off due to mutations in the high-FE2+ (HFE) genes that lead to a lack of hepcidin or resistance on the part of ferroportin to hepcidin binding. This is the major mechanism for the increased iron stores in the body. Hepcidin is a liver-derived peptide, which impairs the release of iron from enterocytes and macrophages by interacting with ferroportin. As a result, iron accumulates in various organs including the liver, which is severely injured and causes the clinically important hemochromatosis. This diagnosis is difficult to establish due to uncharacteristic features. Among these are asthenia, joint pain, arthritis, chondrocalcinosis, diabetes mellitus, hypopituitarism, hypogonadotropic hypogonadism, and cardiopathy. Diagnosis is initially suspected by increased serum levels of ferritin, a non-specific parameter also elevated in inflammatory diseases that must be excluded to be on the safer diagnostic side. Diagnosis is facilitated if ferritin is combined with elevated fasting transferrin saturation, genetic testing, and family screening. Various diagnostic attempts were published as algorithms. However, none of these were based on evidence or quantitative results derived from scored key features as opposed to other known complex diseases. Among these are autoimmune hepatitis (AIH) or drug-induced liver injury (DILI). For both diseases, the scored diagnostic algorithms are used in line with artificial intelligence (AI) principles to ascertain the diagnosis. The first-line therapy of hemochromatosis involves regular and life-long phlebotomy to remove iron from the blood, which improves the prognosis and may prevent the development of end-stage liver disease such as cirrhosis and hepatocellular carcinoma. Liver transplantation is rarely performed, confined to acute liver failure. In conclusion, ferroptosis, ROS, the gut microbiome, and concomitant alcohol abuse play a major contributing role in the development and clinical course of genetic hemochromatosis, which requires early diagnosis and therapy initiation through phlebotomy as a first-line treatment.

Haemochromatosis revisited

Haemochromatosis is a genetic disease caused by hepcidin deficiency, responsible for an increase in intestinal iron absorption. Haemochromatosis is associated with homozygosity for the HFE p.Cys282Tyr mutation. However, rare cases of haemochromatosis (non-HFE haemochromatosis) can also be caused by pathogenic variants in other genes (such as HJV, HAMP, TFR2 and SLC40A1). A working group of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society) has concluded that the classification based in different molecular subtypes is difficult to be adopted in clinical practice and has proposed a new classification approaching clinical questions and molecular complexity. The aim of the present review is to provide an update on classification, pathophysiology and therapeutic recommendations.