A form of inherited hyperferritinemia associated with bi-allelic pathogenic variants of STAB1.

Hyperferritinemia is a frequent finding in several conditions, both genetic and acquired. We previously studied eleven healthy subjects from eight different families presenting with unexplained hyperferritinemia. Their findings suggested the existence of an autosomal-recessive disorder. We carried out whole-exome sequencing to detect the genetic cause of hyperferritinemia. Immunohistochemistry and flow cytometry assays were performed on liver biopsies and monocyte-macrophages to confirm the pathogenic role of the identified candidate variants. Through a combined approach of whole-exome sequencing and homozygosity mapping, we found bi-allelic STAB1 variants in ten subjects from seven families. STAB1 encodes the multifunctional scavenger receptor stabilin-1. Immunohistochemistry and flow cytometry analyses showed absent or markedly reduced stabilin-1 in liver samples, monocytes, and monocyte-derived macrophages. Our findings show a strong association between otherwise unexplained hyperferritinemia and bi-allelic STAB1 mutations suggesting the existence of another genetic cause of hyperferritinemia without iron overload and an unexpected function of stabilin-1 in ferritin metabolism.

How I treat non-transfusion-dependent ß-thalassemia.

The intricate interplay of anemia and iron overload under the pathophysiological umbrella of ineffective erythropoiesis in non-transfusion-dependent ß-thalassemia (NTDT) results in a complex variety of clinical phenotypes that are challenging to diagnose and manage. In this article, we use a clinical framework rooted in pathophysiology to present 4 common scenarios of patients with NTDT. Starting from practical considerations in the diagnosis of NTDT, we delineate our strategy for the longitudinal care of patients who exhibit different constellations of symptoms and complications. We highlight the use of transfusion therapy and novel agents, such as luspatercept, in the patient with anemia-related complications. We also describe our approach to chelation therapy in the patient with iron overload. Although tackling every specific complication of NTDT is beyond the scope of this article, we touch on the management of the various morbidities and multisystem manifestations of the disease.

Haemochromatosis.

Haemochromatosis is one of the most common genetic diseases affecting patients of northern European ancestry. It is overdiagnosed in patients without iron overload and is underdiagnosed in many patients. Early diagnosis by genetic testing and therapy by periodic phlebotomy can prevent the most serious complications, which include liver cirrhosis, liver cancer, and death. This Seminar includes an update on the origins of haemochromatosis; and an overview pathophysiology, genetics, natural history, signs and symptoms, differential diagnoses, treatment with phlebotomy, outcomes, and future directions.

Diagnosing aceruloplasminemia: navigating through red herrings.

A 58-year-old female was found to have hyperferritinemia (Serum ferritin:1683 ng/mL) during work-up for mild normocytic anemia. Transferrin saturation(TSAT) was low-normal. Magnetic resonance imaging (MRI) abdomen showed evidence of hepatic iron deposition. Liver biopsy showed 4 + hepatic iron deposition without any evidence of steatosis or fibrosis. Quantitative liver iron was elevated at 348.3 µmol/g dry liver weight [Reference range(RR): 3-33 µmol/g dry liver weight]. She was presumptively diagnosed with tissue iron overload, cause uncertain. A diagnosis of ferroportin disease (FD) was considered, but the pattern of iron distribution in the liver, mainly within the hepatic parenchyma (rather than in the hepatic Kupffer cells seen in FD), and the presence of anemia (uncommon in FD) made this less likely. She was treated with intermittent phlebotomy for over a decade with poor tolerance due to worsening normocytic to microcytic anemia. A trial of deferasirox was done but it was discontinued after a month due to significant side effects. During the course of treatment, her ferritin level decreased. Over the past 1.5 years, she developed progressively worsening neurocognitive decline. MRI brain showed areas of susceptibility involving basal ganglia, midbrain and cerebellum raising suspicion for metabolic deposition disease. Neuroimaging findings led to testing for serum copper and ceruloplasmin levels which were both found to be severely low. Low serum copper, ceruloplasmin levels and neuroimaging findings led us to consider Wilson disease however prior liver biopsy showing elevated hepatic iron rather than hepatic copper excluded the diagnosis of Wilson disease. After shared decision making, ceruloplasmin gene analysis was not pursued due to patient's preference and prohibitive cost of testing. The diagnosis of aceruloplasminemia was ultimately made. The biochemical triad of hyperferritinemia, low-normal TSAT and microcytic anemia should raise the possibility of aceruloplasminemia. Since neurological manifestations are rare in most inherited iron overload syndromes, neurological symptoms in a patient with tissue iron overload should prompt consideration of aceruloplasminemia as a differential diagnosis.

Hereditary hemochromatosis with homozygous C282Y HFE mutation: possible clinical model to assess effects of elevated reactive oxygen species on the development of cardiovascular disease.

Hereditary hemochromatosis with the homozygous C282Y HFE mutation (HH-282H) is a genetic condition which causes iron overload (IO) and elevated reactive oxygen species (ROS) secondary to the IO. Interestingly, even after successful iron removal therapy, HH-282H subjects demonstrate chronically elevated ROS. Raised ROS are also associated with the development of multiple cardiovascular diseases and HH-282H subjects may be at risk to develop these complications. In this narrative review, we consider HH-282H subjects as a clinical model for assessing the contribution of elevated ROS to the development of cardiovascular diseases in subjects with fewer confounding clinical risk factors as compared to other disease conditions with high ROS. We identify HH-282H subjects as a potentially unique clinical model to assess the impact of chronically elevated ROS on the development of cardiovascular disease and to serve as a clinical model to detect effective interventions for anti-ROS therapy.

Iron Overload in Children With Leukemia; Identification of a Cutoff Value for Serum Ferritin Level.

OBJECTIVE: To determine the prevalence of iron overload in children with acute lymphoblastic leukemia (ALL) after treatment cessation and establish a cutoff value for serum ferritin level as an indicator of iron overload. BACKGROUND: Early detection and monitoring of iron overload in patients with leukemia is crucial. METHODS: In this prospective cohort study, 66 pediatric patients with ALL who were treated at a tertiary referral center affiliated with Shiraz University of Medical Sciences in Shiraz, Southern Iran, were investigated from July 2020 to December 2022. Serum ferritin levels were measured 6 months after treatment completion. T2* magnetic resonance imaging of the liver and heart was done for all patients. The receiver operating characteristic curve was used to illustrate the area under the receiver operating characteristic curve to assess the diagnostic value of serum ferritin level and total transfusion volume. RESULTS: A total of 24 patients (36.4%) had iron overload in the heart or liver based on T2 magnetic resonance imaging findings. Serum ferritin level was a highly accurate diagnostic marker for iron overload in pediatric patients with ALL, with a sensitivity of 95.8%, and specificity of 85.7% for a cutoff value of 238.5 ng/mL. Also, blood transfusion was a good predictor of iron overload a sensitivity of 75% and specificity of 81% for a cutoff value of 28.3 mL/kg. CONCLUSION: We identified specific cutoff values for serum ferritin and blood transfusion volume to predict iron overload with high sensitivity and specificity. These markers offer a cost-effective and accessible approach for periodic screening of iron deposition, particularly in resource-constrained settings.

Genetically predicted biomarkers of iron homeostasis and risk of non-ischemic cardiomyopathy: A mendelian randomization study.

BACKGROUND AND AIMS: Both iron overload and iron deficiency have been associated with cardiovascular diseases in observational studies. Previous Mendelian Randomization (MR) studies discovered a protective effect of higher iron status on coronary atrial disease, while a neutral effect on all-cause heart failure. Using two-sample MR, we evaluated how genetically predicted systemic iron status affects the risk of non-ischemic cardiomyopathy and different phenotypes. METHODS AND RESULTS: Two-sample MR analyses were performed to estimate the causal effect of four biomarkers of systemic iron status on diagnosed cardiomyopathy and its subtypes in 242,607 participants from the FinnGen research project. The level of transferrin saturation was significantly associated with an increased risk of cardiomyopathy (OR, 1.17; 95% CI, 1.13-1.38) when using nine separately selected genetic instruments. An increase in genetically determined serum iron (odds ratio [OR] per standard deviation [SD], 1.25; 95% confidence interval [CI], 1.13-1.38) and ferritin (OR, 1.49; 95% CI, 1.02-2.18) were associated with an increased risk of cardiomyopathy. Total iron binding capacity, a marker of reduced iron status, was inversely linked with cardiomyopathy (OR, 0.80; 95% CI, 0.65-0.98). The risk effect of iron status was more evident in hypertrophic cardiomyopathy and related heart failure. CONCLUSIONS: These analyses support the causal effect of increased systemic iron status on a higher risk of non-ischemic cardiomyopathy. A screening test for cardiomyopathy should be considered in patients with evidence of iron overload. Future study is needed for exploring the mechanism of these causal variants on cardiomyopathy.

Research on the clinical factors of cardiac iron deposition in children with beta-thalassemia major.

Magnetic resonance imaging (MRI) T2* is the gold standard for detecting iron deposition in cardiac tissue, but the technique has limitations and cannot be fully performed in paediatric thalassemia patients. The aim of this study was to analyse clinical data to identify other predictors of cardiac iron deposition. A retrospective analysis was performed on 370 children with ß-TM. According to the cardiac MRI results, patients were allocated to a cardiac deposition group and noncardiac deposition group. Multivariate analysis revealed that genotype and corrected QT interval were associated with cardiac iron deposition, indicating that the-ß0/ß0 genotype conferred greater susceptibility to cardiac iron deposition. Receiver operating characteristic curve (ROC) analysis was performed, and the area under the curve (AUC) of genotype was 0.651. The AUC for the corrected QT interval was 0.711, at a cut-off value of 418.5 ms. ROC analysis of the combined genotype and corrected QT interval showed an AUC of 0.762 with 81.3% sensitivity and 64.7% specificity. Compared to patients with the ß+/ß+ and ß0ß+ genotypes, ß0ß0 children with ß-TM were more likely to have cardiac iron deposition.  Conclusion: The genotype and QTc interval can be used to predict cardiac iron deposition in children with ß-TM who are unable to undergo MRI T2 testing.

Iron chelation therapy.

Iron overload is a pathological condition resulting from a congenital impairment of its regulation, increased intestinal iron absorption secondary to bone marrow erythroid hyperplasia, or a chronic transfusional regimen. In normal conditions, intracellular and systemic mechanisms contribute to maintaining iron balance. When this complex homeostatic mechanism fails, an iron overload could be present. Detecting an iron overload is not easy. The gold standard remains the liver biopsy, even if it is invasive and dangerous. Identifying iron using noninvasive techniques allowed a better understanding of the rate of iron overload in different organs, with a low risk for the patient. Estimating serum ferritin (mg/L) is the easiest and, consequently, the most employed diagnostic tool for assessing body iron stores, even if it could be a not specific method. The most common hematological causes of iron overload are myelodysplastic syndromes, sickle cell disease, and thalassemia. In all of these conditions, three drugs have been approved for the treatment of iron overload: deferiprone, deferoxamine, and deferasirox. These chelators have been demonstrated to help lower tissue iron levels and prevent iron overload complications, improving event-free survival (EFS). Nowadays, the decision to start chelation and which chelator to choose remains the joint decision of the clinician and patient.

The clinical relevance of detectable plasma iron species in iron overload states and subsequent to intravenous iron-carbohydrate administration.

Many disorders of iron homeostasis (e.g., iron overload) are associated with the dynamic kinetic profiles of multiple non-transferrin bound iron (NTBI) species, chronic exposure to which is associated with deleterious end-organ effects. Here we discuss the chemical nature of NTBI species, challenges with measuring NTBI in plasma, and the clinical relevance of NTBI exposure based on source (iron overload disorder vs. intravenous iron-carbohydrate complex administration). NTBI is not a single entity but consists of multiple, often poorly characterized species, some of which are kinetically non-exchangeable while others are relatively exchangeable. Prolonged presence of plasma NTBI is associated with excessive tissue iron accumulation in susceptible tissues, with consequences, such as endocrinopathy and heart failure. In contrast, intravenous iron-carbohydrate nanomedicines administration leads only to transient NTBI appearance and lacks evidence for association with adverse clinical outcomes. Assays to measure plasma NTBI are typically technically complex and remain chiefly a research tool. There have been two general approaches to estimating NTBI: capture assays and redox-activity assays. Early assays could not avoid capturing some iron from transferrin, thus overestimating NTBI. By contrast, some later assays may have promoted the donation of NTBI species to transferrin during the assay procedure, potentially underestimating NTBI levels. The levels of transferrin saturation at which NTBI species have been detectable have varied between different methodologies and between patient populations studied.

Can biomarkers predict myocardial iron overload in children with thalassemia major?

AIM: Beta-thalassemia major requires regular blood transfusions throughout life, which in turn leads to iron accumulation in the body. While cardiac T2* MRI is the gold standard in determining cardiac iron accumulation, it is not always feasible, which has led to the search for new biomarkers. Herein, the value of growth differentiation factor-15, galectin-3, and N-terminal pro-B-type natriuretic peptide in predicting cardiac iron accumulation is investigated in asymptomatic children with beta-thalassemia major. MATERIALS AND METHOD: Forty-one patients aged 11-21 years and 41 age-, gender-, body mass index-matched healthy controls were included. Serum growth differentiation factor-15, galectin-3, and N-terminal pro-B-type natriuretic peptide levels were compared between the patients and controls. Additionally, the relations of these biomarkers with cardiac and liver T2 * MRI were investigated in the patients. RESULTS: In the patients, growth differentiation factor-15, galectin-3, and N-terminal pro-B-type natriuretic peptide levels were higher than healthy controls (p < 0.001, p = 0.025, p < 0.001, respectively). There were no significant correlations of growth differentiation factor-15 and N-terminal pro-B-type natriuretic peptide levels with both cardiac and liver T2 * MRI measurements. While there was no significant correlation of serum galectin-3 with cardiac T2 * MRI measurements, a negative correlation was found with liver T2 * MRI measurements (p = 0.040, rho = -0.325). CONCLUSION: All three biomarkers investigated in this study failed to predict myocardial iron accumulation in asymptomatic children with beta-thalassemia major. However, a weak relation between serum galectin-3 level and hepatic iron accumulation was demonstrated.

New Perspectives on Circulating Ferritin: Its Role in Health and Disease.

The diagnosis of iron disturbances usually includes the evaluation of serum parameters. Serum iron is assumed to be entirely bound to transferrin, and transferrin saturation-the ratio between the serum iron concentration and serum transferrin-usually reflects iron availability. Additionally, serum ferritin is commonly used as a surrogate of tissue iron levels. Low serum ferritin values are interpreted as a sign of iron deficiency, and high values are the main indicator of pathological iron overload. However, in situations of inflammation, serum ferritin levels may be very high, independently of tissue iron levels. This presents a particularly puzzling challenge for the clinician evaluating the overall iron status of the patient in the presence of an inflammatory condition. The increase in serum ferritin during inflammation is one of the enigmas regarding iron metabolism. Neither the origin, the mechanism of release, nor the effects of serum ferritin are known. The use of serum ferritin as a biomarker of disease has been rising, and it has become increasingly diverse, but whether or not it contributes to controlling the disease or host pathology, and how it would do it, are important, open questions. These will be discussed here, where we spotlight circulating ferritin and revise the recent clinical and preclinical data regarding its role in health and disease.

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.

An update on the US adult thalassaemia population: a report from the CDC thalassaemia treatment centres.

Thalassaemia is caused by genetic globin defects leading to anaemia, transfusion-dependence and comorbidities. Reduced survival and systemic organ disease affect transfusion-dependent thalassaemia major and thalassaemia intermedia. Recent improvements in clinical management have reduced thalassaemia mortality. The therapeutic landscape of thalassaemia may soon include gene therapies as functional cures. An analysis of the adult US thalassaemia population has not been performed since the Thalassemia Clinical Research Network cohort study from 2000 to 2006. The Centers for Disease Control and Prevention supported US thalassaemia treatment centres (TTCs) to compile longitudinal information on individuals with thalassaemia. This dataset provided an opportunity to evaluate iron balance, chelation, comorbidities and demographics of adults with thalassaemia receiving care at TTCs. Two adult cohorts were compared: those over 40 years old (n = 75) and younger adults ages 18-39 (n = 201). The older adult cohort was characterized by higher numbers of iron-related comorbidities and transfusion-related complications. By contrast, younger adults had excess hepatic and cardiac iron and were receiving combination chelation therapy. The ethnic composition of the younger cohort was predominantly of Asian origin, reflecting the demographics of immigration. These findings demonstrate that comprehensive care and periodic surveys are needed to ensure optimal health and access to emerging therapies.

Clinical view versus guideline adherence in ferritin monitoring and initiating iron chelation therapy in patients with myelodysplastic syndromes.

OBJECTIVES: In patients with myelodysplastic syndromes (MDS) with >20 transfusions and ferritin levels >1000 µg/L, international guidelines recommend iron chelation therapy (ICT). The study's objective was to determine guideline adherence and the intensity of ferritin monitoring in clinical practice. METHODS: We performed an observational population-based study using the HemoBase Registry, which contains data of all MDS patients diagnosed since 2005 in Friesland, the Netherlands. Clinical information on transfusions, ferritin measurements, ICT, and clinical performance as defined by age ≤ 80 years, Charlson Comorbidity Index <2 and lower-risk MDS was collected from health records. RESULTS: Two hundred and thirty seven of 292 patients (81.1%) received ≥1 transfusion, and 121 (41.4%) received >20 transfusions. In 57 of these 121 patients (47.1%), ferritin measurements were performed at least once. Clinical performance was significantly associated with monitoring ferritin around the 20th transfusion (RR: 2.49, p = .016). Clinical performance was also associated with initiating ICT (RR: 5.99, p < .001). ICT was offered to 22.3% (n = 25) of eligible patients. CONCLUSIONS: In this population-based study, ferritin levels were measured in <50% of MDS patients who received >20 transfusions, and clinical performance was significantly associated with measuring ferritin. Our study suggests that in heavily transfused MDS patients, ferritin monitoring is primarily based on patients' clinical performance rather than guideline recommendations.

Relationship between pancreatic iron overload, glucose metabolism and cardiac complications in sickle cell disease: An Italian multicentre study.

OBJECTIVES: Evidence about the cross-talk between iron, glucose metabolism, and cardiac disease is increasing. We aimed to explore the link of pancreatic iron by Magnetic Resonance Imaging (MRI) with glucose metabolism and cardiac complications (CC) in sickle cell disease (SCD) patients. METHODS: We considered 70 SCD patients consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. Iron overload was quantified by R2* technique and biventricular function by cine images. Macroscopic myocardial fibrosis was evaluated by late gadolinium enhancement technique. Glucose metabolism was assessed by the oral glucose tolerance test. RESULTS: Patients with an altered glucose metabolism showed a significantly higher pancreas R2* than patients with normal glucose metabolism. Pancreatic siderosis emerged as a risk factor for the development of metabolic alterations (OddsRatio 8.25, 95%confidence intervals 1.51-45.1; p = .015). Global pancreas R2* values were directly correlated with mean serum ferritin levels and liver iron concentration. Global pancreas R2* was not significantly associated with global heart R2* and macroscopic myocardial fibrosis. Patients with history of CC showed a significantly higher global pancreas R2* than patients with no CC. CONCLUSIONS: Our findings support the evaluation of pancreatic R2* by MRI in SCD patients to prevent the development of metabolic and cardiac disorders.

Thalassemia in the Philippines.

For an archipelago that has a rich history of trade with overseas merchants and colonial rule, the Philippine Islands are models of ethnic and cultural diversity, including hereditary blood disorders such as hemoglobinopathies. Pending a government-led comprehensive national screening program, available cluster data provides evidence of the prevalence of thalassemia in the country. The National Blood Services Act of 1994 was enacted to promote voluntary blood donation to address the supply of blood products but falls short in addressing the immense blood transfusion requirements of the thalassemic community. Iron overload monitoring and management is a considerable challenge due to high cost of laboratory tests and iron chelators on top of minimal health insurance coverage for the majority of Filipino patients with thalassemia. Continuous engagement with the thalassemia patient community and multi sectoral efforts are the means to ensure sustained improvement in the delivery of care.

Hepcidin-to-Ferritin Ratio as an Early Diagnostic Index of Iron Overload in ß-Thalassemia Major Patients.

Hepcidin (HEPC) hormone production is expected to be elevated in cases accompanying iron overload, but the opposite impact of ineffective erythropoiesis in ß-thalassemia major (ß-TM) patients overrides this effect. The role of the HEPC-to-ferritin (FER) ratio and its components in iron metabolism along with their diagnostic cutoff values, sensitivity, specificity, and accuracy in ß-TM patients with iron overload, were examined in this study. This was a 1:1 case-control study with 120 participants, ages ranging from 2 to 30 years of both sexes, who were assigned into two groups: 60 ß-TM patients with iron overload, and a control group, comprising 60 healthy individuals matched by gender and age. In the present study, we found slightly elevated serum HEPC concentration (21.9 ng/mL) compared to the controls (9.9 ng/mL), which was not statistically significant (p =0.1), and the median HEPC-to-FER ratio of the cases was significantly lower than the controls, with the median case-control difference of (-0.366; p < 0.001). Our results revealed a statistically significant impact (p < 0.001) of mean age on the serum HEPC level with the inverse linear correlation of (-0.487, p < 0.001). The area under the curve of the HEPC-to-FER ratio was 0.999 and the optimum cutoff value was 0.046 ng/mL (p < 0.001) with 100.0% sensitivity and 98.3% specificity. In conclusion, we found that serum HEPC-to-FER ratio, with an accuracy of 99.2%, may serve as an excellent index for the diagnosis of iron overload in ß-TM patients differentiating them from nonthalassemic controls.

Assessment of plasma catecholamines in patients with dysmetabolic iron overload syndrome.

BACKGROUND: Dysmetabolic iron overload syndrome (DIOS) is characterized by hyperferritinemia and normal transferrin saturation level with components of metabolic syndrome (MS). Among cases of MS, we determined those with DIOS and their characterizations, then we evaluated the association between plasma catecholamines status and hypertension in DIOS. METHODS: We compared 101 hypertensive patients with 50 healthy participants (control group). Iron (iron, transferrin, and ferritin), insulin, and plasma catecholamine (adrenaline, noradrenaline, and dopamine), profiles were measured for both groups. Homeostasis model assessment of insulin resistance index and transferrin saturation were also calculated. RESULTS: Out of 101 hypertensive patients, 64 were diagnosed with MS, and 6 of the latter met the DIOS diagnostic criteria. Significantly, DIOS patients were older and had lower body mass index (BMI) compared with hypertensive non-DIOS patients with p-values of (0.026), and (0.033), respectively. Adrenaline, noradrenaline, and dopamine levels did not differ significantly between DIOS and non-DIOS patients. CONCLUSIONS: Of the MS patients, 9.3% were diagnosed with DIOS. Accordingly, complete iron profiling should be performed routinely in the cases of MS for early diagnosis of DIOS, to prevent future complications. Further studies are required to test the hypothesis linking older age and lower BMI with the pathogenesis of DIOS.

Non-Transfusion-Dependent Thalassemia: A Panoramic Review.

Non-transfusion-dependent thalassemia (NTDT) has been considered less severe than its transfusion-dependent variants. The most common forms of NTDT include ß-thalassemia intermedia, hemoglobin E/beta thalassemia, and hemoglobin H disease. Patients with NTDT develop several clinical complications, despite their regular transfusion independence. Ineffective erythropoiesis, iron overload, and hypercoagulability are pathophysiological factors that lead to morbidities in these patients. Therefore, an early and accurate diagnosis of NTDT is essential to ascertaining early interventions. Currently, several conventional management options are available, with guidelines suggested by the Thalassemia International Federation, and novel therapies are being developed in light of the advancement of the understanding of this disease. This review aimed to increase clinicians' awareness of NTDT, from its basic medical definition and genetics to its pathophysiology. Specific complications to NTDT were reviewed, along with the risk factors for its development. The indications of different therapeutic options were outlined, and recent advancements were reviewed.