Hereditary hyperferritinaemia-cataract syndrome: a challenging diagnosis for the hepatogastroenterologist

Iron overload disorders

Iron overload disorders represent a variety of conditions that lead to increased total body iron stores and resultant end-organ damage. An elevated ferritin and transferrin-iron saturation can be commonly encountered in the evaluation of elevated liver enzymes. Confirmatory homeostatic iron regulator (HFE) genetic testing for C282Y and H63D, mutations most encountered in hereditary hemochromatosis, should be pursued in evaluation of hyperferritinemia. Magnetic resonance imaging with quantitative assessment of iron content or liver biopsy (especially if liver disease is a cause of iron overload) should be used as appropriate. A secondary cause for iron overload should be considered if HFE genetic testing is negative for the C282Y homozygous or C282Y/H63D compound heterozygous mutations. Differential diagnosis of secondary iron overload includes hematologic disorders, iatrogenic causes, or chronic liver diseases. More common hematologic disorders include thalassemia syndromes, myelodysplastic syndrome, myelofibrosis, sideroblastic anemias, sickle cell disease, or pyruvate kinase deficiency. If iron overload has been excluded, evaluation for causes of hyperferritinemia should be pursued. Causes of hyperferritinemia include chronic liver disease, malignancy, infections, kidney failure, and rheumatic conditions, such as adult-onset Still's disease or hemophagocytic lymphohistiocytosis. In this review, we describe the diagnostic testing of patients with suspected hereditary hemochromatosis, the evaluation of patients with elevated serum ferritin levels, and signs of secondary overload and treatment options for those with secondary iron overload.

Ferritin L-subunit gene mutation and hereditary hyperferritinaemia cataract syndrome (HHCS): a case report and literature review

ABSTRACTObjectives: Hereditary hyperferritinaemia cataract syndrome (HHCS) is an autosomal dominant disease characterized by high serum ferritin levels and juvenile bilateral cataracts. It is often caused by mutations in the iron response element (IRE) of the ferritin L-subunit (FTL) gene. Here, we report a 73-year-old woman who presented to clinic with persistently elevated serum ferritin and family history of juvenile bilateral cataracts in four generations.Methods: Exome sequencing was used to identify the mutation of the FTL gene. Moreover, Sanger sequencing was performed to validate the mutation in the proband. We also reviewed the FLT gene mutations in published HHCS cases to provide experience for accurate diagnosis of similar patients.Results: A heterozygous mutation at position +33 (c.-167C > T, chr19:49468598) of the FTL gene was identified in the patient.Discussion: HHCS should be considered in the differential diagnosis of hyperferritinemia, especially in the presence of normal serum iron concentration and transferrin saturation.Conclusion: For patients with unexplained hyperferritinemia and bilateral cataracts who have experienced early vision loss, the establishment of genetic counseling is essential to diagnose other family members who are at risk in time.Abbreviations: FTL: ferritin L-subunit; HHCS: hereditary hyperferritinaemia cataract syndrome; IDT: integrated DNA technologies; IRE: iron response element; IRP: iron regulatory proteins; MRI: magnetic resonance imaging; SNV: single nucleotide variant; UTR: untranslated region.

A retrospective series of conditions and mortality associated with extreme hyperferritinaemia in adults

BACKGROUND

Serum ferritin is commonly used in the diagnosis of iron deficiency anaemia. However, extreme hyperferritinaemia suggests a significant illness, including the differential diagnosis of haemophagocytic lymphohistiocytosis (HLH), which is rare and associated with a high mortality, particularly if untreated. This series aims to identify the causes and associated mortality of severe hyperferritinaemia in patients seen at a teaching hospital in London, UK.

METHOD

Demographic and medical data were collected for all patients over 18 years of age with extreme hyperferritinaemia (defined as serum ferritin levels of ≥4000 mcg/L). Conditions associated with hyperferritinaemia and in-hospital mortality were identified from medical records, laboratory data and discharge and death notification.

RESULTS

One hundred and fifty-five cases of extreme hyperferritinaemia in adults were identified. Associated conditions included iron overload (35%), malignancy (24%), infectious disease (21%) and hepatocellular disease (12%). Autoimmune disease and HLH resulted in significantly higher median peak ferritin levels compared with all cases (10 616 mcg/L, P < .01 and 19 138 mcg/L, P < .05, respectively). Patients with confirmed HLH had the highest median peak ferritin. Uncommon infections were identified in this series, and included such as dengue, syphilis, HIV and murine typhus. HLH had been confirmed in seven patients (5%). In five patients (3%) no clear cause for raised ferritin was identified. Overall mortality in the whole cohort was 14% (n = 22), but there was a very high mortality of 80% in the group where no cause was found for the hyperferritinaemia, and these patients were significantly more likely to die during the index admission (P < .01).

CONCLUSION

Extreme hyperferritinaemia is associated with a broad differential diagnosis of significant medical conditions, including iron overload, infections, cancer and liver disease. Rare infectious causes were also identified, and this series reports a greater proportion of cases of HLH than has previously reported. Unexplained hyperferritinaemia was associated with significant mortality.

Diagnosis of hyperferritinemia in routine clinical practice

The discovery of hyperferritinemia is often fortuitous, revealed in results from a laboratory screening or follow-up test. The aim of the diagnostic procedure is therefore to identify its cause and to identify or rule out hepatic iron overload, in a three-stage process. In the first step, clinical findings and several simple laboratory tests are sufficient to detect four of the most frequent causes of high ferritin concentrations: alcoholism, inflammatory syndrome, cytolysis, and metabolic syndrome. None of these causes is associated with substantial hepatic iron overload. If transferrin saturation is high (> 50%), hereditary hemochromatosis will be considered in priority. In the second phase, rarer diseases will be sought. Among them, only chronic hematologic diseases (acquired or congenital) and excessive iron intake or infusions (patients on chronic dialysis and high-level athletes) are at risk of iron overload. In the third stage, if a doubt persists about the cause or if the ferritin concentration is very high or continues to rise, it is essential to verify the hepatic iron concentration to rule out overload. The principal examination to guide diagnosis and treatment is hepatic MRI to assess its iron concentration. It is essential to remember that more than 40% of patients with hyperferritinemia have several causes simultaneously present.

Non-HFE hemochromatosis: pathophysiological and diagnostic aspects

Rare genetic iron overload diseases are an evolving field due to major advances in genetics and molecular biology. Genetic iron overload has long been confined to the classical type 1 hemochromatosis related to the HFE C282Y mutation. Breakthroughs in the understanding of iron metabolism biology and molecular mechanisms led to the discovery of new genes and subsequently, new types of hemochromatosis. To date, four types of hemochromatosis have been identified: HFE-related or type1 hemochromatosis, the most frequent form in Caucasians, and four rare types, named type 2 (A and B) hemochromatosis (juvenile hemochromatosis due to hemojuvelin and hepcidin mutation), type 3 hemochromatosis (related to transferrin receptor 2 mutation), and type 4 (A and B) hemochromatosis (ferroportin disease). The diagnosis relies on the comprehension of the involved physiological defect that can now be explored by biological and imaging tools, which allow non-invasive assessment of iron metabolism. A multidisciplinary approach is essential to support the physicians in the diagnosis and management of those rare diseases.

Extreme hyperferritinaemia; clinical causes

There are many causes of raised serum ferritin concentrations including iron overload, inflammation and liver disease to name but a few examples. Cases of extreme hyperferritinaemia (serum ferritin concentration equal to or greater than 10 000 ug/l) are being reported in laboratories but the causes of this are unclear. We conducted an audit study to explore this further. Extreme hyperferritinaemia was rare with only 0.08% of ferritin requests displaying this. The main causes of extreme hyperferritinaemia included multiple blood transfusions, malignant disease, hepatic disease and suspected Still's disease.

Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series

Introduction

Hepatologists and internists often encounter patients with unexplained high serum ferritin concentration. After exclusion of hereditary hemochromatosis and hemosiderosis, rare disorders like hereditary hyperferritinemia cataract syndrome should be considered in the differential diagnosis. This autosomal dominant syndrome, that typically presents with juvenile bilateral cataracts, was first described in 1995 and has an increasing number of recognized molecular defects within a regulatory region of the L-ferritin gene (FTL).

Case presentation

Two patients (32 and 49-year-old Caucasian men) from our ambulatory clinic were suspected as having this syndrome and a genetic analysis was performed. In both patients, sequencing of the FTL 5' region showed previously described mutations within the iron responsive element (FTL c.33 C > A and FTL c.32G > C).

Conclusion

Hereditary hyperferritinemia cataract syndrome should be considered in all patients with unexplained hyperferritinemia without signs of iron overload, particularly those with juvenile bilateral cataracts. Liver biopsy and phlebotomy should be avoided in this disorder.

The hereditary hyperferritinemia-cataract syndrome: a family study

Ferritin is an acute-phase reactant that is elevated in the course of infectious, inflammatory, autoimmune, and oncological diseases and the hemophagocytic syndrome. In asymptomatic patients, isolated hyperferritinemia may be due to different causes depending on whether or not it is accompanied by iron overload. Hyperferritinemia values above 300 ng/ml and an excess of body iron levels may be indicative of hemochromatosis. However, if such values develop in the absence of iron overload, they may be secondary to hemochromatosis type 4a (ferroportin disease) or more often to hereditary hyperferritinemia-cataract syndrome (HHCS; Aguilar-Martinez et al., Am J Gastroenterol 100:1185-1194, 2005; Ferrante et al., Eur J Gastroenterol Hepatol 17:1247-1253, 2005). HHCS results from different mutations in the L-ferritin gene (FTL) on chromosome 19 (19q13.1), causing autosomal dominant transmission (Bertola et al., Curr Drug Targets Immune Endocr Metabol Disord 4:93-105, 2004). We present a child with HHCS due to the allelic variant c.-167C>T (C33T) in the iron-responsive element region of the FTL gene. When pediatricians encounter an asymptomatic patient with isolated hyperferritinemia in the absence of iron overload, they should consider the possibility of HHCS, especially if other members of the family have developed cataracts from a young age.

Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder

The hereditary hyperferritinaemia-cataract syndrome (HHCS) is characterised by an autosomal dominant cataract and high levels of serum ferritin without iron overload. The cataract develops due to L-ferritin deposits in the lens and its pulverulent aspect is pathognomonic. The syndrome is caused by mutations within the iron-responsive element of L-ferritin. These mutations prevent efficient binding of iron regulatory proteins 1 and 2 to the IRE in L-ferritin mRNA, resulting in an unleashed ferritin translation. This paper reviews all 31 mutations (27 single nucleotide transitions and four deletions) that have been described since 1995. Laboratory test showing hyperferritinaemia, normal serum iron and normal transferrin saturation are indicative for HHCS after exclusion of other causes of increased ferritin levels (inflammation, malignancy, alcoholic liver disease) and should prompt an ophthalmological consultation for diagnostic confirmation. Invasive diagnostics such as liver biopsy are not indicated. HHCS is an important differential diagnosis of hyperferritinaemia. Haematologists, gastroenterologists and ophthalmologists should be aware of this syndrome to spare patients from further invasive diagnosis (liver biopsy), and also from a false diagnosis of hereditary haemochromatosis followed by venesections. Patients diagnosed with HHCS should be counselled regarding the relative harmlessness of this genetic disease, with early cataract surgery as the only clinical consequence.

Phenotypic and behavioral defects induced by iron exposure can be transferred to progeny in Caenorhabditis elegans

OBJECTIVE

Previous work has showed that excess iron accumulation is harmful to reproduction and even promotes death; however, whether the multiple biological toxicity of iron (Fe) exposure could be transferred to progeny remains unknown. The present study used Caenorhabditis elegans to analyze the multiple toxicities of iron exposure and their possible transferable properties.

METHODS

Three concentrations of iron sulfate solution (2.5 micromol/L, 75 micromol/L, and 200 micromol/L) were used. The endpoints of lifespan, body size, generation time, brood size, head thrash and body bend frequencies, and chemotaxis plasticity were selected to investigate Fe toxicity and its effect on progeny in Caenorhabditis elegans.

RESULTS

The Fe toxicity could cause multiple biological defects in a dose-dependent manner by affecting different endpoints in nematodes. Most of the multiple biological defects and behavior toxicities could be transferred from Fe-exposed Caenorhabditis elegans to their progeny. Compared to the parents, no recovery phenotypes were observed for some of the defects in the progeny, such as body bend frequency and life span. We further summarized the defects caused by Fe exposure into 2 groups according to their transferable properties.

CONCLUSION

Our results suggest that Fe exposure could cause multiple biological defects, and most of these severe defects could be transferred from Fe exposed nematodes to their progeny.

Current approach to hemochromatosis

Iron overload diseases of genetic origin are an ever changing world, due to major advances in genetics and molecular biology. Five major categories are now established: HFE-related or type1 hemochromatosis, frequently found in Caucasians, and four rarer diseases which are type 2 (A and B) hemochromatosis (juvenile hemochromatosis), type 3 hemochromatosis (transferrin receptor 2 hemochromatosis), type 4 (A and B) hemochromatosis (ferroportin disease), and a(hypo)ceruloplasminemia. Increased duodenal iron absorption and enhanced macrophagic iron recycling, both due to an impairment of hepcidin synthesis, account for the development of cellular excess in types 1, 2, 3, and 4B hemochromatosis whereas decreased cellular iron egress is involved in the main form of type 4A) hemochromatosis and in aceruloplasminemia. Non-transferrin bound iron plays an important role in cellular iron excess and damage. The combination of magnetic resonance imaging (for diagnosing visceral iron overload) and of genetic testing has drastically reduced the need for liver biopsy. Phlebotomies remain an essential therapeutic tool but the improved understanding of the intimate mechanisms underlying these diseases paves the road for innovative therapeutic approaches.