Introduction
Approximately 800-1500 mg of iron mainly deposited in the liver, spleen and bone marrow macrophages is the usual amount of this metal present in the human body. If iron intake exceeds the depot capacities of these organs, it will start to accumulate in the parenchyma of different organs in the form of soluble ferritin, and later in the form of insoluble hemosiderin. The disease characterized by iron accumulation and its toxic effects on the liver, heart, pancreas, pituitary gland, joints and skin is called hemochromatosis (1).
Based on the specific cause, hemochromatoses are divided into two groups of hereditary or genetic type and secondary type hemochromatosis. Hereditary hemochromatoses are subdivided into hereditary hemochromatosis (HH), hereditary hemolytic anemias and congenital atransferrinemia, whereas secondary hemochromatoses are subdivided into blood transfusion related type, iron therapy related type, hepatitis related type and African nutritional hemochromatosis caused by the intake of alcohol drinks prepared in iron containers (1).
Hereditary hemochromatosis is an autosomal recessive disorder. Although the prevalence of clinically manifested HH depends on the screening methods used, it has been estimated to approximately 0.5% (2). There are three genetic subtypes of HH. The most common subtype is type 1 characterized by Cys282Tyr mutation of the HFE gene located on the short arm of chromosome 6. HFE gene product is responsible for the blood iron uptake into the duodenal crypt cells. This HFE function is mediated by transferrin receptor. The described mutation disables regulation of the blood iron content and leads to enhanced expression of proteins responsible for iron transfer and increased iron absorption (2). A homozygous form of Cys282Tyr mutation has been detected in approximately 83% of all HH cases with clinical manifestations (3).
The disease symptoms usually become apparent after age 40 in male and around age 50 in female patients. Clinical manifestations of hemochromatosis include frequent infections, liver disease, intensive skin pigmentation, diabetes mellitus, arthropathies, cardiomyopathies and impotence. Most patients are asymptomatic, whereas the most common cause for visiting doctor’s office are fatigue and arthralgia. In most cases, the only suspect laboratory finding is increased blood iron concentration (1).
Early recognition of HH is crucial to prevent the most severe sequels like liver cirrhosis and hepatocellular carcinoma (4). For this purpose, the following laboratory tests should be obtained: blood iron (> 32 μmol/L), ferritin concentration (> 500 μg/L), transferrin saturation (> 62%), liver biopsy and molecular analysis of known HFE polymorphisms. Appropriate cut off values are given in parentheses. Along with these tests, ultrasonography of the abdomen and other imaging methods like computerized tomography or magnetic resonance can be performed.
The aim of patient treatment is to reduce blood iron concentration to normal values. It can be achieved by therapeutic phlebotomy and treatment with chelating agents like desferrioxamine. The most important prognostic factor at the time of diagnosis is the presence or absence of liver fibrosis or cirrhosis. Patients treated before the occurrence of liver cirrhosis have normal life expectancy, whereas untreated patients die in 2 years, most frequently from heart failure, cirrhosis or hepatocellular carcinoma.
Thalassemias are a heterogeneous group of hereditary hemolytic anemias caused by genetic defects that lead to inadequate synthesis of alpha- and/or beta hemoglobin chains. The beta-thalassemia subgroup includes the syndromes of defective beta-hemoglobin chain synthesis and is subdivided into three clinical types of beta-thalassemia major, intermedia and minor. Because of the large number and diversity of underlying mutations, their determination is not part of the routine laboratory work-up in beta-thalassemia patients. The diagnosis and classification of beta-thalassemia are made on the basis of complete blood count, hemoglobin electrophoresis and clinical presentation. The simplest form, beta-thalassemia minor (BTM), i.e. heterozygous beta-thalassemia, is manifested by microcytosis and hypochromia, with only slight anemia, while hemoglobin electrophoresis shows slight increase of hemoglobin A2 (hemoglobin with two alpha- and two delta-chains). Other laboratory findings usually fall within the reference ranges. Hemochromatosis, severe anemia, bone deformities and other severe manifestations compatible with beta-thalassemia major or intermedia are not characteristic of BTM (2).
Besides HH, severe forms of beta-thalassemia can also lead to hemochromatosis. Furthermore, simultaneous inheritance of some HFE mutation and BTM may also occur. In these cases, the symptoms of hemochromatosis are more pronounced (5-7). Even some of the heterozygous HFE carriers suffering from BTM may develop hemochromatosis related symptoms (8,9). All these facts point to the need of an overview of the diagnostic work-up required for timely identification of patients with coinheritance of these two diseases and of the procedures appropriate for the risk stratification for the development of hemochromatosis in these patients. Such an overview is given as part of the following case report in which we present a patient that had simultaneously inherited a homozygous Cys282Tyr HFE mutation and BTM.
Materials and methods
Case report
In 2007, A. A., a 46-year-old man, was admitted to Department of Infectious Diseases, Osijek University Hospital, for febrile condition and poor general state. Ultrasonography of the abdomen done on admission revealed a diffuse liver lesion and splenomegaly. Magnetic resonance imaging was performed to elucidate nonspecific neurologic symptoms like headache and facial skin sensations, and revealed demyelination zones in the frontal part of the brain. Based on the symptoms, acute meningoencephalitis was suspected during his stay at Department of Infectious Diseases.
As family history data revealed the patient’s mother to suffer from BTM, no detailed work-up for the patient’s microcytic anemia was done. Complete blood count showed the following results: red blood cell concentration 4.82 x 1012 /L, hemoglobin concentration 102 g/L, hematocrit 0.316 L/L, mean cellular volume 65.5 fL, mean cellular hemoglobin content 21.2 pg, mean cellular hemoglobin concentration 323 g/L and platelet concentration 72x109 /L. Other laboratory findings included borderline serum iron concentration (31.6 μmol/L), significantly increased ferritin (3257 μg/L) and transferrin saturation (77%), while the levels of liver enzymes were within the reference range (aspartate aminotransferase 30 U/L, alanine aminotransferase 25 U/L, gamma-glutamyltransferase 43 U/L). Along with complete blood count values that were compatible with BTM, serum concentration of iron, ferritin and transferrin saturation pointed to the possible hemochromatosis. In order to confirm the BTM diagnosis and to determine the type of the disease, hemoglobin electrophoresis and haptoglobin concentration measurements were additionally performed to yield a slightly increased percentage of hemoglobin A2 (4.3%) and normal values of hemoglobin F (1.2%) and haptoglobin concentration (0.43 g/L); these findings confirmed the diagnosis of BTM (2).
As the values of serum iron, ferritin and transferrin saturation exceeded the values expected in BTM and hepatosplenomegaly was found, the patient underwent liver biopsy. Microscopic examination revealed pigment cirrhosis-hemochromatosis. Subsequent diagnostic work-up included PCR-RFLP analysis of HFE gene, which identified the homozygous form of Cys282Tyr polymorphism. At this point, therapeutic phlebotomy and desferrioxamine therapy were initiated.
After two years of treatment, the patient was feeling well. Ultrasonography showed enlarged spleen (approximately 17x2 cm) and the liver of regular size, while electrocardiogram revealed no abnormalities. Microcytic anemia persisted (red blood cell concentration 5.07 x 1012 /L, hemoglobin concentration 114 g/L, mean cellular volume 69.8 fL, mean hemoglobin content 22.5 pg), but liver enzymes activities were increased (aspartate aminotransferase 81 U/L, alanine aminotransferase 75 U/L, gamma-glutamyltransferase 54 U/L). The HbA1c percentage showed borderline increase (6.5%), along with elevated ferritin (2694 μg/L) and transferrin saturation (70%). Serum iron concentration was within the reference interval (29.2 μmol/L). Other laboratory parameters did not change significantly in comparison to their initial values.
Methods
The imaging techniques employed were ultrasonography, which was carried out on a Sonoline device with 3.5 MHz G50 probe (Siemens AG, Erlangen, Germany), and magnetic resonance imaging, which was carried out on an EPIOS device with magnetic field strength of 0.5 T (Shimadzu Co., Kyoto, Japan). Electrocardiogram was recorded on a PageWriter 100 instrument (Hewlett-Packard, Palo Alto, USA). Complete blood count was determined on an SF-3000 counter (Sysmex Corporation, Cobe, Japan) and EDTA anticoagulant was used. With the exception of automated biochemical analyses described below, all other analyses from this group were performed on an AU 640 device (Olympus, Hamburg, Germany). A BN ProSpec nephelometer (Siemens AG, Erlangen, Germany) was used for haptoglobin determination, and a Dimension RXL device (Siemens AG, Erlangen, Germany) for determination of HbA1c percentage in whole blood taken on EDTA anticoagulant. Hemoglobin electrophoresis was performed by the application of Hydragel Hemoglobin K20 kit (Sebia, Inc., Norcross, GA, USA), while histopathology of the liver biopsy sample was performed after tissue processing by Prussian blue dye. HFE gene Cys282Tyr polymorphism was analyzed by the PCR-RFLP procedure described in the literature (3).
Discussion
There are several literature reports on simultaneous inheritance of beta-thalassemia and different HFE mutations (5-9). Unusual presentation of these diseases in the patient presented and severe symptoms like cirrhosis and demyelination caused by the homogeneous form of Cys282Tyr HFE mutation coinherited with BTM makes this case worthy of closer examination. In most cases described in the literature, patients suffered from heterozygous types of HFE mutations coinherited with beta-thalassemia. On admission, the patient did not exhibit any overt sign of hemochromatosis. On the contrary, the leading symptoms were suggestive of diagnostic procedures for acute meningoencephalitis. Liver enzyme activities were within the reference intervals and this finding made the diagnostic work-up even more complex. Highly increased values of ferritin and transferrin saturation proved to be of key importance. These two parameters of extended laboratory work-up were the first to show the underlying hemochromatosis.
Suspicion of beta-thalassemia was indicated in the patient’s history and the findings of complete blood count were compatible with this notion. At first, the significance of this disease for the etiology of hemochromatosis was not clear. Although beta-thalassemia could lead to hemochromatosis, only a severe form of beta-thalassemia or HH could lead to functional hyposplenism, along with morphological hypersplenism that presents in the form of frequent infections, as was the case in our patient (2). Although rarely, the neurologic symptoms recorded in our patient may also manifest in hemochromatosis patients (10,11). These manifestations are only compatible with the severe forms of beta-thalassemia or HH. Therefore, it was of essential to determine the type of beta-thalassemia. Only after hemoglobin electrophoresis it was evident that beta-thalassemia minor alone could not have caused such symptoms.
As mentioned above, the patient had already developed liver cirrhosis as one of the most severe hemochromatosis symptoms. Hemochromatosis and liver cirrhosis verified by biopsy along with BTM pointed to the most probable cause of the patient’s illness, i.e. some kind of HFE polymorphism. The homozygous form of HH was confirmed by molecular diagnosis. It was only the diagnosis of coinherited BTM and homozygous HH that could accurately explain the relatively severe and unusual symptoms of hemochromatosis such as cirrhosis and demyelination.
The results obtained at two years of therapy introduction showed only minor improvement of iron metabolism. Unfortunately, there was a simultaneous increase in the liver enzyme activities and borderline functional impairment of endocrine pancreas. Based on these results, it is concluded that there therapy should be modified, either by the introduction of more frequent therapeutic phlebotomy or change in the dosage or type of iron chelator therapy. Since the patient suffers from two diseases which, under certain conditions, can lead to hemochromatosis manifestations, it is necessary to examine his family members in order to prevent the disease development.
Conclusion
Although simultaneous inheritance of two diseases is not very likely, the case presented shows that this scenario should not be overlooked on diagnostic work-up. In the case presented, serum ferritin, transferrin saturation, hemoglobin electrophoresis and Cys282Tyr HFE polymorphism analysis proved to be the key factors to reach the accurate diagnosis. Without these laboratory results, serum ferritin and transferrin saturation in particular, the recognition of hemochromatosis as a possible underlying cause of unusual symptoms that led to the patient’s hospitalization, would have been considerably delayed.
The case presented shows that beta-thalassemia should be carefully examined as a possible cause of hemochromatosis development. The treatment for beta-thalassemia would not alleviate the symptoms that require hospitalization. On the other hand, BTM could lead to hemochromatosis manifestation even in heterozygous HFE mutation carriers. The fact that the patient presented suffered from both BTM and the homozygous form of HH explains the unusually severe hemochromatosis presentation at the time of diagnosis.
Finally, due to the long period of latency, early recognition of HH improves the patient’s chances for normal life expectancy and quality. The fact that simple and widely available laboratory tests could accurately reveal HH and beta-thalassemia justifies their use in the screening of patient families for carriers and asymptomatic members. Due to the diverse presentation and complex interplay of the causes of hemochromatosis in these patients, only careful interpretation of the results obtained can ensure establishment of accurate diagnosis and treatment.
Acknowledgments
We want to thank the radiologists, hematologists, infectologists, pathologists and biochemists from our institution for their technical support. We are highly grateful to Asst. Prof. A. M. Šimundić, PhD and her associates for HFE polymorphism analysis and Professor B. Dmitrović, PhD, for critical reading of the text and useful suggestions.
