This guideline has been approved by the American Association for the Study of Liver
Diseases (AASLD) and represents the position of the association.
Preamble
These recommendations provide a data-supported approach to establishing guidelines.
They are based on the following: (1) a formal review and analysis of the recently
published world literature on the topic; (2) the American College of Physicians Manual
for Assessing Health Practices and Designing Practice Guidelines
1; (3) guideline policies including the AASLD Policy on the Development and Use of
Practice Guidelines and the American Gastroenterological Association's Policy Statement
on the Use of Medical Practice Guidelines
2; and (4) the experience of the authors in regard to hemochromatosis.
To more fully characterize the available evidence supporting the recommendations,
the AASLD Practice Guidelines Committee has adopted the classification used by the
Grading of Recommendation Assessment, Development, and Evaluation (GRADE) workgroup
with minor modifications (Table 1).3 The strength of recommendations in the GRADE
system are classified as strong (class 1) or weak (class 2). The quality of evidence
supporting strong or weak recommendations is designated by one of three levels: high
(level A), moderate (level B), or low-quality (level C).
Table 1
Grading of Recommendations, Assessment, Development, and Evaluation (GRADE)
Strength of Recommendation
Criteria
Strong (1)
Factors influencing the strength of the recommendation included the quality of the
evidence, presumed patient-important outcomes, and cost
Weak (2)
Variability in preferences and values, or more uncertainty. Recommendation is made
with less certainty, or higher cost or resource consumption
Quality of Evidence
Criteria
High (A)
Further research is unlikely to change confidence in the estimate of the clinical
effect
Moderate (B)
Further research may change confidence in the estimate of the clinical effect
Low (C)
Further research is very likely to impact confidence on the estimate of clinical effect
Intended for use by physicians, these recommendations suggest preferred approaches
to the diagnostic, therapeutic, and preventive aspects of care. They are intended
to be flexible in contrast to standards of care, which are inflexible policies to
be followed in every case. Specific recommendations are based on relevant published
information.3,4
Introduction
Hereditary hemochromatosis (HH) remains the most common, identified, genetic disorder
in Caucasians. Although its geographic distribution is worldwide, it is seen most
commonly in populations of northern European origin, particularly Nordic or Celtic
ancestry, in which it occurs with a prevalence of approximately 1 per 220-250 individuals.5,6
The pathophysiologic predisposition to increased, inappropriate absorption of dietary
iron may lead to the development of life-threatening complications of cirrhosis, hepatocellular
carcinoma (HCC), diabetes, and heart disease. The principal HFE gene defect was first
described in 1996, and is a G-to-A missense mutation leading to the substitution of
tyrosine for cysteine at amino acid position 282 of the protein product (C282Y).7
C282Y homozygotes account for 80%-85% of typical patients with HH.8 There are two
other regularly identified mutations, one in which aspartate is substituted for histidine
at amino acid position 63 (H63D), and the other in which cysteine is substituted for
serine at amino acid position 65 (S65C). These are generally not associated with iron
loading unless seen with C282Y as a compound heterozygote, C282Y/H63D or C282Y/S65C
(Fig. 1). Over the last 10 years, mutations of other genes coding for iron regulatory
proteins have been implicated in inherited iron overload syndromes (e.g., hepcidin,
hemojuvelin, transferrin receptor 2, and ferroportin). These are thought to account
for most of the non-HFE forms of HH.9
Fig. 1
Schematic representation of the protein product of HFE. Most of the protein is extracellular.
There is a short cytoplasmic tail and three extracellular alpha loops. The three principal
mutations are identified.
With the advent of genetic testing in the late 1990s, HFE-related HH is now frequently
identified in asymptomatic probands and in presymptomatic relatives of patients who
are known to have the disease. Accordingly, a genetic diagnosis can be applied to
individuals who have not yet developed any phenotypic expression. Therefore, these
individuals have a “genetic susceptibility” to developing iron overload but may never
do so, for reasons that are still to be determined.6,10–12 This observation has changed
the way we think about hemochromatosis. Twenty years ago, it was considered that all
individuals who were genetically susceptible would ultimately have evidence of phenotypic
expression. Now, it is clear that phenotypic expression only occurs in approximately
70% of C282Y homozygotes, and fewer than 10% of C282Y homozygotes will develop severe
iron overload accompanied by organ damage and clinical manifestations of hemochromatosis.10,12
This acknowledgment has led to a recognition of the different stages and progression
of hemochromatosis identified at a consensus conference of the European Association
for the Study of Liver Diseases in 2000.13 These stages are defined as follows:
Stage 1 refers to those patients with the genetic disorder with no increase in iron
stores who have “genetic susceptibility.”
Stage 2 refers to those patients with the genetic disorder who have phenotypic evidence
of iron overload but who are without tissue or organ damage.
Stage 3 refers to those individuals who have the genetic disorder with iron overload
and have iron deposition to the degree that tissue and organ damage occurs.
This organizational schema is important to allow clinicians to categorize patients
who have positive genetic test results.
Causes of Iron Overload
The current classification of iron overload syndromes divides patients into three
groups (Table 2): (1) those who have inherited causes of iron overload, (2) those
who have various causes of secondary iron overload, and (3) a small miscellaneous
group. Approximately 85%-90% of patients who have inherited forms of iron overload
are homozygous for the C282Y mutation in HFE, with a small minority who are compound
heterozygotes, meaning that one allele has the C282Y mutation and one allele has the
H63D or the S65C mutation. The remaining 10%-15% of patients who have inherited forms
of iron overload most likely have mutations in one of the other aforementioned genes
involved in iron homeostasis.9 Causes of secondary iron overload are divided between
those causes related to iron loading anemias, those related to chronic liver disease,
transfusional iron overload, and miscellaneous causes. Oral iron ingestion does not
lead to iron overload except in genetically predisposed individuals or those who have
ineffective erythropoiesis.
Table 2
Classification of Iron Overload Syndromes
Hereditary Hemochromatosis
HFE-related
C282Y/C282Y
C282Y/H63D
Other HFE mutations
Non–HFE-related
Hemojuvelin (HJV)
Transferrin receptor-2 (TfR2)
Ferroportin (SLC40A1)
Hepcidin (HAMP)
African iron overload
Secondary Iron Overload
Iron-loading anemias
Thalassemia major
Sideroblastic
Chronic hemolytic anemia
Aplastic anemia
Pyruvate kinase deficiency
Pyridoxine-responsive anemia
Parenteral iron overload
Red blood cell transfusions
Iron–dextran injections
Long-term hemodialysis
Chronic liver disease
Porphyria cutanea tarda
Hepatitis C
Hepatitis B
Alcoholic liver disease
Nonalcoholic fatty liver disease
Following portocaval shunt
Dysmetabolic iron overload syndrome
Miscellaneous
Neonatal iron overload
Aceruloplasminemia
Congenital atransferrinemia
Other inherited forms of iron overload, classified as non–HFE-related HH, are juvenile
hemochromatosis and iron overload resulting from mutations in the genes for transferrin
receptor 2 (TfR2), or ferroportin (SLC40A1).9 Juvenile HH is characterized by rapid
iron accumulation. Mutations in two different genes (hemojuvelin and hepcidin) have
been shown to cause two forms of juvenile HH.14 The more common mutation occurs in
the hemojuvelin (HJV) gene on chromosome 1q.15 Mutations in the hepcidin gene (HAMP)
also produce a form of juvenile HH, but this is much less common.14 Hepcidin is a
25–amino acid peptide produced in the liver that down-regulates iron absorption. Mutations
in the TfR2 gene produce an autosomal recessive form of HH that is clinically similar
to HFE-related HH.16 These mutations may cause abnormal iron sensing by hepatocytes,
which is the predominant site of TfR2 expression. The distribution of excess iron
is similar to that in HFE-related HH, namely, primarily in hepatic parenchymal cells.16
A rare autosomal dominant form of HH results from two categories of mutations in the
gene for the iron transporter protein, ferroportin. “Loss-of-function” mutations decrease
the cell surface localization of ferroportin, thereby reducing its ability to export
iron.17,18 The result is iron deposition primarily in macrophages, and this disorder
is called “ferroportin disease”. The second category of mutation includes “gain-of-function”
ferroportin mutations that abolish hepcidin-induced ferroportin internalization and
degradation18; distribution of iron is similar to HFE-related HH, concentrating predominantly
in parenchymal cells.
African iron overload occurs primarily in sub-Saharan Africa and is now considered
to be the result of a non–HFE-related genetic abnormality that can be exacerbated
by dietary iron loading.19 Some individuals with African iron overload drink an iron-rich
fermented beverage, but iron overload can also occur in people who do not drink this
beverage.19
Causes of Secondary Iron Overload and Miscellaneous Disorders
Individuals who absorb excessive amounts of iron as a result of an underlying defect
other than any of the previously mentioned inherited disorders have secondary iron
overload.20 The most common causes of secondary iron overload are individuals with
ineffective erythropoiesis, parenteral iron overload, and liver disease. Individuals
who receive blood transfusions and who have transfusional or parenteral iron overload
should be distinguished from those who have other causes of secondary iron overload.
Parenteral iron overload is always iatrogenic, in that blood or iron (given parenterally)
must be ordered by a health care provider prior to its administration. Many individuals
with ineffective erythropoiesis who have decreased utilization of iron by the bone
marrow also have transfusional iron overload because of a requirement for transfusions.20
Recently, it has been found that neonatal hemochromatosis is actually a form of congenital
alloimmune hepatitis with subsequent iron deposition.21 In these cases, immune-mediated
liver injury in the fetus is associated with the development of iron overload. Administration
of intravenous immunoglobulin during pregnancy slows or prevents the development of
this condition.22 Other rare miscellaneous disorders include congenital atransferrinemia
and aceruloplasminemia.
Pathophysiology
There are four main categories of pathophysiological mechanisms of HH that should
be mentioned: (1) the increased absorption of dietary iron in the upper intestine,
(2) decreased expression of the iron-regulatory hormone hepcidin, (3) the altered
function of HFE protein, and (4) tissue injury and fibrogenesis induced by iron.
Intestinal Iron Absorption
The first link between HFE protein and cellular iron metabolism resulted from the
observation that the HFE protein along with β2-microglobulin forms a complex with
transferrin receptor-1 (TfR1).23 This physical association was observed in cultured
cells and in duodenal crypt enterocytes, which have been considered to be the predominant
site of regulation of dietary iron absorption. The observation that HFE protein and
TfR1 were physically associated led to a number of investigations of the effect of
HFE protein on TfR1-mediated iron uptake and cellular iron stores.24 The “crypt cell
hypothesis” of iron regulation is now regarded as much less important since the discovery
of the central role of hepcidin in the regulation of iron metabolism.
Hepcidin
Hepcidin is a 25–amino acid peptide that influences systemic iron status.25 It is
considered to be the principal iron-regulatory hormone. Alteration in the regulation
of hepcidin plays an important role in the pathogenesis of hemochromatosis. Hepcidin
is expressed predominantly in hepatocytes and is secreted into the circulation. It
binds to ferroportin, which is found in macrophages and on the basolateral surface
of enteroctyes. When hepcidin binds to ferroportin, the ferroportin is internalized
and degraded and iron export by these two cell types (macrophages and enterocytes)
is inhibited.26 Hepcidin expression induced by excess iron or inflammation results
in decreased intestinal iron absorption and diminished iron release from macrophages.25
In contrast, hepcidin expression is decreased by iron deficiency, ineffective erythropoiesis,
and hypoxia, with resulting increases in iron absorption from the intestine and release
of iron from macrophages.25 Mutations in human disease or murine knockouts of the
genes for HFE, hemojuvelin, hepcidin, or TfR2 decrease hepcidin expression with a
resulting increase in intestinal iron absorption via up-regulation of ferroportin
levels in enterocytes.25
Studies have revealed that iron-induced regulation of hepcidin expression involves
a bone morphogenetic protein 6 (BMP6)-dependent signaling pathway.27 BMP6 binds to
a specific receptor on hepatocytes triggering SMAD protein–dependent activation of
hepcidin expression. Selective inhibition of BMP6 signaling abrogates iron-induced
up-regulation of hepcidin.27 Hemojuvelin is a BMP6 coreceptor, and it facilitates
the binding of BMP6 to its receptor; knockout of the HJV gene markedly decreases BMP6
signaling in hepcidin expression and causes iron overload.28
HFE Protein
The extracellular domain of HFE protein consists of three loops with intramolecular
disulfide bonds within the second and third loops7 (Fig. 1). The structure of the
HFE protein is similar to that of other major histocompatibility complex class-1 proteins,
but evidence indicates that HFE protein does not participate in antigen presentation.29
HFE protein is physically associated with β2-microglobulin, similar to other major
histocompatibility complex class-1 molecules. The major mechanisms by which HFE influences
iron-dependent regulation of hepcidin remain unclear. HFE can bind to both TfR2 and
to the classic transferrin receptor TfR1.23,30 In addition, both HFE and TfR2 may
interact with HJV, suggesting that a complex of HFE and TfR2 may play a regulatory
role in BMP6 signaling.28 One proposed explanation suggests that the complex of TfR1
and HFE acts as an iron sensor at the cell membrane of the hepatocyte.30 As transferrin
saturation (TS) increases, diferric transferrin displaces HFE from TfR1, thereby making
HFE available to bind to TfR2. It is postulated that the complex of HFE and TfR2 then
influences hepcidin expression. Figure 2 summarizes these interactions.31
Fig. 2
Summary of interactions between duodenal enterocytes, hepatocytes, and macrophages
in iron homeostasis regulated by hepcidin. FPN, ferroportin. (Adapted from Camaschella
C. BMP6 orchestrates iron metabolism. Nat Genet 2009;41:386–388. Used with permission
from Nature Genetics. Copyright © 2009, Nature Publishing Group).
Liver Damage
Another major pathophysiologic mechanism in HH relates to the liver damage that results
from iron overload.32 In patients with advanced HH, hepatic fibrosis and cirrhosis
are the principal pathological findings. Numerous studies using experimental hepatic
iron overload have identified iron-dependent oxidative damage and associated impairment
of membrane-dependent functions of mitochondria, microsomes, and lysosomes.33,34 One
hypothesis is that iron-induced lipid peroxidation occurs in hepatocytes and causes
hepatocellular injury or death. Kupffer cells become activated byproducts released
from injured iron-loaded hepatocytes and produce profibrogenic cytokines, which in
turn stimulate hepatic stellate cells to synthesize increased amounts of collagen,
thereby leading to pathologic fibrosis.32,35
Clinical Features
Hemochromatosis is increasingly being recognized by clinicians. Nonetheless, it is
still underdiagnosed, because it is often considered a rare disorder that is manifested
by the clinical findings seen in fully established disease consisting of cirrhosis,
diabetes, and skin pigmentation (so-called “bronze diabetes”). Genetic susceptibility
(C282Y homozygosity) for hemochromatosis is seen in approximately one in 250 Caucasians;
however, fully expressed disease with end-organ manifestations is seen in fewer than
10% of these individuals.10,12 The reasons for the lack of phenotypic expression are
unknown. It may involve interactions with gene products of other proteins involved
in iron homeostasis (with or without mutation). This can explain the discrepancy between
the high incidence of C282Y homozygosity in Caucasians (one in 250) versus how infrequently
the full clinical manifestations of the disease are seen (approximately one in 2500).
The heterozygote genotype (C282Y/wild type) is found in approximately one in 10 individuals
and may be associated with elevated serum iron markers, but without associated tissue
iron overload or damage.
Clinical manifestations in patients reported in series from the 1950s to the 1980s
showed that most reported patients had classic symptoms and findings of advanced hemochromatosis
(Table 3).36–38 By the 1990s, HH was increasingly being identified in patients who
had abnormal iron studies on routine chemistry panels or by patients having been identified
by family screening.39,40 When patients with HH were identified in this way, approximately
75% of them did not have symptoms and did not exhibit any of the end-stage manifestations
of the disease. Currently, in large population screening studies, only approximately
70% of C282Y homozygotes are found to have an elevated ferritin level indicative of
increased iron stores (Table 4), and only a small percentage of these patients have
clinical consequences of iron storage disease.6,10,12,41,42 More men than women have
increased ferritin levels. Nonetheless, it is still important for clinicians to be
aware of the symptoms that patients may exhibit and the physical findings with which
they can present.
Table 3
Principal Clinical Features in Hereditary Hemochromatosis
Study (Year)
Features
Milder et al.37 (1980)
Edwards et al.36 (1980)
Niederau et al.38 (1985)
Adams et al.39 (1991)
Bacon and Sadiq40 (1997)
Number of subjects
34†
35*
163*
37‡
40
Symptoms (%)
Weakness, lethargy
73
20
83
19
25
Abdominal pain
50
23
58
3
0
Arthralgias
47
57
43
40
13
Loss of libido, impotence
56
29
38
32
12
Cardiac failure symptoms
35
0
15
3
0
Physical and Diagnostic Findings (%)
Cirrhosis (biopsy)
94
57
69
3
13
Hepatomegaly
76
54
83
3
13
Splenomegaly
38
40
13
–
–
Loss of body hair
32
6
20
–
–
Gynecomastia
12
–
8
–
–
Testicular atrophy
50
14
–
–
–
Skin pigmentation
82
43
75
9
5
Clinical diabetes
53
6
55
11
–
*
Patient selection occurred by both clinical features and family screening.
†
Only symptomatic index cases were studied.
‡
Discovered by family studies.
Table 4
Prevalence of C282Y Homozygotes Without Iron Overload in Large Screening Studies
Population Sample
Country
n
Prevalence of Homozygotes
C282Y Homozygotes with Normal Ferritin Level (%)
Primary care (12)
USA
41,038
1 in 270
35
General public (11)
Norway
65,238
1 in 220
13
Primary care (6)
North America
99,711
1 in 333
31
General public (10)
Australia
29,676
1 in 146
32
Total
235,663
1 in 240
30
When patients present with symptoms, hemochromatosis should be considered when there
are complaints of fatigue, right upper quadrant abdominal pain, arthralgias, (typically
of the second and third metacarpophalangeal joints), chondrocalcinosis, impotence,
decreased libido, and symptoms of heart failure or diabetes (Table 5). Similarly,
physical findings of an enlarged liver, particularly in the presence of cirrhosis,
extrahepatic manifestations of chronic liver disease, testicular atrophy, congestive
heart failure, skin pigmentation, changes of porphyria cutanea tarda (PCT), or arthritis
should raise the suspicion of hemochromatosis (Table 6). Many of these features are
indicative of disease processes other than hemochromatosis, but the thoughtful clinician
will make sure that hemochromatosis has been considered when patients who exhibit
these symptoms or signs are seen. Currently, most new patients with HH come to medical
attention because of screening, such as in family studies, or by evaluation of abnormal
laboratory studies by primary care physicians. In older series of patients with HH,
when patients were identified by symptoms or physical findings of the disease, women
typically presented approximately 10 years later than men, and there were approximately
10 times as many men presenting as women. This sex difference is likely because of
menstrual blood loss and maternal iron loss during pregnancy having a “protective”
effect for women. More recently, with a greater proportion of patients identified
by screening studies, the age of diagnosis for women and men has equalized, and the
numbers of men and women identified are roughly equivalent.6,10 Nonetheless, the proportion
of C282Y homozygous women with definite disease manifestations (e.g., liver disease,
arthritis) is significantly lower than men (1% versus 25%, respectively).10
Table 5
Symptoms in Patients with HH
Asymptomatic
Abnormal serum iron studies on routine screening chemistry panel
Evaluation of abnormal liver tests
Identified by family screening
Nonspecific, systemic symptoms
Weakness
Fatigue
Lethargy
Apathy
Weight loss
Specific, organ-related symptoms
Abdominal pain (hepatomegaly)
Arthralgias (arthritis)
Diabetes (pancreas)
Amenorrhea (cirrhosis)
Loss of libido, impotence (pituitary, cirrhosis)
Congestive heart failure (heart)
Arrhythmias (heart)
Table 6
Physical Findings in Patients with HH
Asymptomatic
No physical findings
Hepatomegaly
Symptomatic
Liver
Hepatomegaly
Cutaneous stigmata of chronic liver disease
Splenomegaly
Liver failure: ascites, encephalopathy, and associated features
Joints
Arthritis
Joint swelling
Chondrocalcinosis
Heart
Dilated cardiomyopathy
Congestive heart failure
Skin
Increased pigmentation
Porphyria cutanea tarda
Endocrine
Testicular atrophy
Hypogonadism
Hypothyroidism
Recommendations:
1. We recommend that patients with abnormal iron studies should be evaluated as patients
with hemochromatosis, even in the absence of symptoms. (A)
2. All patients with evidence of liver disease should be evaluated for hemochromatosis.
(1B)
Diagnosis
The clinical diagnosis of hemochromatosis is based on documentation of increased iron
stores, demonstrated by elevated serum ferritin levels, which reflects an increase
in hepatic iron content. HH can be further defined genotypically by the familial occurrence
of iron overload associated with C282Y homozygosity or C282Y/H63D compound heterozygosity.
Serologic iron markers (TS, ferritin) are widely available, and the majority of patients
with HH are now identified while still asymptomatic and without evidence of hepatic
fibrosis or cirrhosis. There are certain high-risk groups that should be targeted
for evaluation, such as those with a family history of HH, those with suspected organ
involvement, and those with chance detection of biochemical and/or radiological abnormalities
suggestive of the possibility of iron overload. It is generally recommended that all
patients with abnormal liver function have iron studies done at some point in their
evaluation. The algorithm outlined in Fig. 3 can provide some further direction regarding
testing and is modified from the version used in the previous AASLD guidelines.42
Fig. 3
An algorithm can provide some further direction regarding testing and treatment for
HH. The algorithm is modified from the version used in the previous AASLD guidelines.
The initial approach to diagnosis is by indirect markers of iron stores, namely TS
or unsaturated iron-binding capacity and serum ferritin (Table 7). TS is calculated
from the ratio of serum iron to total iron-binding capacity. In some laboratories,
the total iron-binding capacity is calculated from the sum of the serum iron and the
unsaturated iron-binding capacity, whereas in others, it is calculated indirectly
from the transferrin concentration in the serum. A recent study, using fasting samples,
has shown no improvement in sensitivity or specificity in the detection of C282Y homozygotes.43
Accordingly, this prior recommendation is no longer absolutely necessary, although
it is advisable to confirm an elevated TS with a second determination and it is not
unreasonable in our opinion to do this on a fasting specimen. Over the years, different
studies have used a variety of cutoff values for TS to identify patients eligible
for further testing. Although a cutoff TS value of 45% is often chosen for its high
sensitivity for detecting C282Y homozygotes, it has a lower specificity and positive
predictive value compared to higher cutoff values. Thus, using a cutoff TS of 45%
will also identify persons with minor secondary iron overload as well as some C282Y/wild-type
heterozygotes, and these cases will require further evaluation.44
Table 7
Laboratory Findings in Patients with HH
Patients with HH
Measurements
Normal Subjects
Asymptomatic
Symptomatic
Blood
Serum iron level (μg/dL)
60-80
150-280
180-300
TS (%)
20-50
45-100
80-100
Serum ferritin level (μg/L)
Men
20-200
150-1000
500-6000
Women
15-150
120-1000
500-6000
Liver
Hepatic iron concentration
μg/g dry weight
300-1500
2000-10,000
8000-30,000
μmol/g dry weight
5-27
36-179
140-550
Hepatic iron index*
<1.0
>1.9
>1.9
Liver histology
Perls' Prussian blue stain
0-1+
2+ to 4+
3+, 4+
*
Hepatic iron index is calculated by dividing the hepatic iron concentration (in μmol/g
dry weight) by the age of the patient (in years). With increased knowledge of genetic
testing results in patients with iron overload, the utility of the hepatic iron index
has diminished.
Serum ferritin has less biological variability than TS, but it has a significant false
positive rate because of elevations related to inflammation. Ferritin can be elevated
in the absence of increased iron stores in patients with necroinflammatory liver disease
(alcoholic liver disease [ALD], chronic hepatitis B and C, nonalcoholic fatty liver
disease [NAFLD]), in lymphomas, and in patients with other nonhepatic chronic inflammatory
conditions. In fact, in the general population, iron overload is not the most common
cause of an elevated ferritin level. Nonetheless, in the absence of other inflammatory
processes, several studies of families with HH have demonstrated that the serum ferritin
concentration provides a valuable correlation with the degree of body iron stores.
In most circumstances, serum ferritin provides additional confirmation of the significance
of an elevated TS in C282Y homozygotes. In a study of individuals <35 years of age,
serum ferritin in the normal range in combination with a TS < 45% had a negative predictive
value of 97% for excluding iron overload.45 In a large study correlating phenotypic
and genotypic markers in a primary care population in California, a serum ferritin
>250 μg/L in men and >200 μg/L in women was positive in 77% and 56%, respectively,
of C282Y homozygotes.12 In the HEIRS (HEmochromatosis and IRon Overload Screening)
study that screened 99,711 North American participants, serum ferritin levels were
elevated (>300 μg/L in men, >200 μg/L in women) in 57% of female and 88% of male C282Y
homozygotes.6 It is recognized that a variety of disease conditions unrelated to iron
overload may cause a nonspecific rise in serum ferritin, and in the absence of an
elevated TS, this rise may be nonspecific. Conversely, iron overload may be present
in a patient with an elevated ferritin and a normal TS, particularly in non–HFE-related
iron overload or in a C282Y/H63D compound heterozygote.46
Serum ferritin levels have an additional value as a predictor of advanced fibrosis
and cirrhosis in confirmed HH. Several studies have demonstrated that a level of serum
ferritin <1000 μg/L is an accurate predictor for the absence of cirrhosis, independent
of the duration of the disease.47–49 A serum ferritin level >1000 μg/L with an elevated
aminotransferase level (alanine aminotransferase [ALT] or aspartate aminotransferase
[AST]) and a platelet count <200 × 109/L predicted the presence of cirrhosis in 80%
of C282Y homozygotes.50
Recommendations:
3. In a patient with suggestive symptoms, physical findings, or family history, a
combination of TS and ferritin should be obtained rather than relying on a single
test. (1B) If either is abnormal (TS ≥ 45% or ferritin above the upper limit of normal),
then HFE mutation analysis should be performed. (1B)
4. Diagnostic strategies using serum iron markers should target high-risk groups such
as those with a family history of HH or those with suspected organ involvement. (1B)
Family Screening
Once a patient with HH has been identified (proband), family screening should be recommended
for all first-degree relatives. For ease of testing, both genotype (HFE mutation analysis)
and phenotype (ferritin and TS) should be performed simultaneously at a single visit.
For children of an identified proband, HFE testing of the other parent is generally
recommended, because if results are normal, the child is an obligate heterozygote
and need not undergo further testing because there is no increased risk of iron loading.51
If C282Y homozygosity or compound heterozygosity is found in adult relatives of a
proband, and if serum ferritin levels are increased, then therapeutic phlebotomy can
be initiated. If ferritin level is normal in these patients, then yearly follow-up
with iron studies is indicated. When identified, C282Y heterozygotes and H63D heterozygotes
can be reassured that they are not at risk for developing progressive or symptomatic
iron overload. Occasional H63D homozygotes can develop mild iron overload.52 However,
it should be recognized that any of these genotypes can be a cofactor for the development
of liver disease when they occur in conjunction with other liver diseases such as
PCT, hepatitis C infection, ALD, or NAFLD. Relatives who are identified as H63D heterozygotes
or H63D homozygotes can be reassured that they are generally not at risk of progressive
iron overload, although they may have minor abnormalities in serum iron measurements
such as TS or ferritin.
Family studies have concluded that many homozygous relatives of probands demonstrate
biochemical and clinical expression of disease.53,54 Furthermore, a recent population
study of approximately 30,000 Caucasian subjects aged 40-69 years identified 203 C282Y
homozygotes (108 females, 95 males). These subjects were evaluated sequentially over
a 12-year period, prior to available knowledge of their genotype. Documented iron
overload-related disease was present in 28% of males and 1% of females, especially
when serum ferritin levels were >1000 μg/L.10
Recommendations:
5. We recommend screening (iron studies and HFE mutation analysis) of first-degree
relatives of patients with HFE-related HH to detect early disease and prevent complications.
(1A)
Liver Biopsy
Since the advent of HFE mutation analysis, liver biopsy has become less important
as a clinical tool in the diagnosis of HH. Liver biopsy should be considered only
for the purpose of determining the presence or absence of advanced fibrosis or cirrhosis,
which does have prognostic value. Identification of cirrhosis may lead to adjustments
in clinical management, such as screening for HCC and esophageal varices (and other
features of portal hypertension).55 The risks of liver biopsy have been reviewed,
with mild bleeding after biopsy reported to be in the range of 1%-6%, and mortality
associated with a complication of less than 1:10,000.56
Serum ferritin levels can help identify patients who may benefit most from having
a liver biopsy. Several studies have demonstrated that C282Y homozygotes with a serum
ferritin >1000 μg/L are at an increased risk of cirrhosis, with a prevalence of 20%-45%.49,50
In contrast, fewer than 2% of C282Y homozygotes with a ferritin level <l000 μg/L at
the time of diagnosis have cirrhosis or bridging fibrosis in the absence of another
risk factor such as excessive alcohol consumption, viral hepatitis, or fatty liver
disease.47–50 A recent study of more than 670 asymptomatic C282Y homozygotes described
the prevalence of advanced hepatic fibrosis.41 In this study, a liver biopsy was performed
in 350 subjects because of elevated serum ferritin levels (using a cutoff of 500 μg/L)
or abnormal serum liver enzyme results, the presence of hepatomegaly, or a combination
of these. The majority of these biopsies were performed for diagnosis of HH prior
to the availability of HFE mutation analysis. Cirrhosis was present in 5.6% of all
males and 1.9% of all females. All subjects with cirrhosis had a hepatic iron concentration
(HIC) >200 μmol/g dry weight (approximately seven times the upper limit of normal).
A serum ferritin level >1000 μg/L had 100% sensitivity and 70% specificity for identification
of cirrhosis. No subject with a serum ferritin level <1000 μg/L had cirrhosis. These
observations must be tempered when patients with HH also consume large amounts of
alcohol. An Australian study showed that >60% of patients with HH who consumed >60
g alcohol/day had cirrhosis, compared to <7% of those who consumed less alcohol.57
Based on these recent studies, it can be concluded that serum ferritin is the single
most important predictor of the presence of advanced hepatic fibrosis in C282Y homozygotes.
Therefore, liver biopsy does not need to be performed when ferritin is <l000 μg/L,
in the absence of excess alcohol consumption and elevated serum liver enzymes.
Patients with elevated serum iron studies, but who lack C282Y homozygosity, should
be considered for liver biopsy if they have elevated liver enzymes or other clinical
evidence of liver disease. These patients may have non-HH liver disease such as NAFLD,
ALD, or chronic viral hepatitis.
When liver biopsy is performed, routine histopathologic evaluation should include
standard hematoxylin–eosin and Masson's trichrome stains as well as Perls' Prussian
blue stains for evaluating the degree and cellular distribution of hepatic iron stores.
In addition, a portion of liver tissue can be obtained for measurement of HIC. It
should be recognized that HIC can also be measured from formalin-fixed, deparaffinized
specimens, but at least 4 mg dry weight of tissue should be available for evaluation.58
Qualitative and semiquantitative methods for grading the degree of stainable hepatic
iron have been described. The Batts–Ludwig system uses an estimation of the proportion
of hepatocytes that stain for iron, ranging from solely zone 1 (periportal) to inclusion
of zones 2 and 3 (pericentral). The grading of iron staining ranges from grade 1 to
grade 4, with grade 4 representing panlobular iron deposition.59 A semiquantitative
“histological hepatic iron index” has been proposed based on the size and density
of iron granules in hepatocytes, sinusoidal lining cells, and portal cells.60 This
formula can be used to calculate a total iron score, and this system has been validated
and found to be useful to differentiate heterozygotes from homozygotes. It is not
widely used outside the research setting.
Hepatic iron index (HII) was first introduced in 1986 and was used frequently to support
a diagnosis of HH when the HII was >1.9, prior to the advent of HFE mutation analysis.61,62
HII, which measures the rate of hepatic iron accretion, is calculated by dividing
the HIC (in μmol/g) by the patient's age in years and was based on the concept that
homozygotes would continue to absorb excess dietary iron throughout their lifetime,
whereas those who were heterozygotes or those with iron overload due to associated
alcohol use would not. Several studies showed that most homozygotes with iron overload
had an HII > l.9 μmol/g/year, whereas patients with other chronic diseases had an
HII < 1.9.63,64 The availability of genetic testing has now shown that phenotypic
expression of homozygosity can occur at a much lower HIC and a much lower HII, and
therefore the HII is no longer routinely used. Recent studies show good correlation
between HIC determined on liver biopsy samples with HIC estimated by proton transverse
relaxation time determined by magnetic resonance imaging.64
Recommendations:
6. Liver biopsy is recommended to stage the degree of liver disease in C282Y homozygotes
or compound heterozygotes if liver enzymes (ALT, AST) are elevated or if ferritin
is >1000 μg/L. (1B)
Role of Liver Biopsy in Non–HFE-related HH
Liver biopsy may provide both diagnostic and prognostic information in patients with
iron overload who are not C282Y homozygotes. Abnormal serum iron studies are identified
in approximately 50% of patients with other liver diseases such as ALD, NAFLD, or
chronic viral hepatitis. Liver biopsy is used to evaluate those patients both from
the standpoint of their underlying disease, determining the stage of fibrosis, and
to determine the degree of iron loading. In the secondary iron overload seen with
other liver diseases, iron deposition is usually mild (1+ to 2+) and generally occurs
in both perisinusoidal lining cells (Kupffer cells) and in hepatocytes in a panlobular
distribution.59 Liver biopsy is also useful to identify the different pattern of iron
overload seen in patients with ferroportin disease, wherein the iron deposition is
predominantly in reticuloendothelial cells or is in a mixed pattern of hepatocytes
and reticuloendothelial cells without a periportal predominance.9
Recommendations:
7. Liver biopsy is recommended for diagnosis and prognosis in patients with phenotypic
markers of iron overload who are not C282Y homozygotes or compound heterozygotes.
(2C)
8. We recommend that in patients with non–HFE-related HH, data on hepatic iron concentration
is useful, along with histopathologic iron staining, to determine the degree and cellular
distribution of iron loading present. (2C)
Treatment of Hemochromatosis
Although there has never been a randomized controlled trial of phlebotomy versus no
phlebotomy in treatment of HH, there is nonetheless, evidence that initiation of phlebotomy
before the development of cirrhosis and/or diabetes will significantly reduce the
morbidity and mortality of HH.65,66 Therefore, early identification and preemptive
treatment of those at risk is generally recommended. This includes treatment of asymptomatic
individuals with homozygous HH and markers of iron overload, as well as others with
evidence of increased levels of hepatic iron. In symptomatic patients, treatment is
also advocated to reduce progression of organ damage. Certain clinical features are
likely to be ameliorated by phlebotomy (malaise, fatigue, skin pigmentation, insulin
requirements for diabetics, and abdominal pain), whereas other features are either
less responsive to iron removal or do not respond at all (Table 8). These include
arthropathy, hypogonadism, and advanced cirrhosis. In some cases, hepatic fibrosis
and cirrhosis show regression after phlebotomy.67 The life-threatening complications
of established cirrhosis, particularly HCC, continue to be a threat to survival even
after adequate phlebotomy. Therefore, patients with cirrhosis should continue to be
screened for HCC following phlebotomy. HCC accounts for approximately 30% of HH-related
deaths, whereas complications of cirrhosis account for an additional 20%.66,68 HCC
is exceptionally rare in noncirrhotic HH, which provides an additional argument for
preventive therapy prior to the development of cirrhosis.69
Table 8
Response to Phlebotomy Treatment in Patients with HH
Reduction of tissue iron stores to normal
Improved survival if diagnosis and treatment before development of cirrhosis and diabetes
Improved sense of well-being, energy level
Improved cardiac function
Improved control of diabetes
Reduction in abdominal pain
Reduction in skin pigmentation
Normalization of elevated liver enzymes
Reversal of hepatic fibrosis (in approximately 30% of cases)
No reversal of established cirrhosis
Elimination of risk of HH-related HCC if iron removal is achieved before development
of cirrhosis
Reduction in portal hypertension in patients with cirrhosis
No (or minimal) improvement in arthropathy
No reversal of testicular atrophy
Phlebotomy remains the mainstay of treatment for HH (Table 9). One unit of blood contains
approximately 200-250 mg iron, depending on the hemoglobin concentration, and should
be removed once or twice per week as tolerated. In patients with HH who may have total
body iron stores >30 g, therapeutic phlebotomy may take up to 2-3 years to adequately
reduce iron stores. Each phlebotomy should be preceded by measurement of the hematocrit
or hemoglobin so as to avoid reducing the hematocrit/hemoglobin to <80% of the starting
value. TS usually remains elevated until iron stores are depleted, whereas ferritin,
which may initially fluctuate, eventually begins to fall progressively with iron mobilization
and is reflective of depletion of iron stores. Serum ferritin analysis should be performed
after every 10-12 phlebotomies (approximately 3 months) in the initial stages of treatment.
It can be confidently assumed that excess iron stores have been mobilized when the
serum ferritin drops to between 50 and 100 μg/L. As the target range of 50-100 μg/L
is approached, testing may be repeated more frequently to preempt the development
of overt iron deficiency. It is not necessary for patients to achieve iron deficiency
and in fact, this should be avoided. Phlebotomy can be stopped at the point at which
iron stores are depleted, and the patient should be assessed for whether they require
maintenance phlebotomy. For reasons that are unclear, not all patients with HH reaccumulate
iron and, accordingly, they may not need a maintenance phlebotomy regimen. Therefore,
the frequency of maintenance phlebotomy varies among individuals, due to the variable
rate of iron accumulation in HH. Some patients (either male or female) require maintenance
phlebotomy monthly, whereas others who reaccumulate iron at a slower rate may need
only 1-2 units of blood removed per year. In the United States, blood acquired by
therapeutic phlebotomy may be used for blood donation in some institutions, and both
the American Red Cross and the U.S. Food and Drug Administration have deemed that
the blood is safe for transfusion.70
Table 9
Treatment of Hemochromatosis
Hereditary hemochromatosis
One phlebotomy (removal of 500 mL blood) weekly or biweekly
Check hematocrit/hemoglobin prior to each phlebotomy. Allow hematocrit/hemoglobin
to fall by no more than 20% of prior level
Check serum ferritin level every 10-12 phlebotomies
Stop frequent phlebotomy when serum ferritin reaches 50-100 μg/L
Continue phlebotomy at intervals to keep serum ferritin between 50 and 100 μg/L
Avoid vitamin C supplements
Secondary iron overload due to dyserythropoiesis
Deferoxamine (Desferal) at a dose of 20-40 mg/kg body weight per day
Deferasirox (Exjade) given orally
Consider follow-up liver biopsy to ascertain adequacy of iron removal
Avoid vitamin C supplements
The decision to treat HH with phlebotomy is straightforward and easy to justify for
patients with evidence of liver disease or other end-organ manifestations. The more
difficult situation is the C282Y homozygote patient with a ferritin level of only
800 μg/L for example, with normal liver tests and no symptoms. Current longitudinal
data are limited; some patients such as this will never progress to more serious problems
and may not need to be treated. However, treatment is easy, safe, inexpensive, and
could conceivably provide societal benefit (blood donation), and thus treatment is
often initiated. Furthermore, there are no available, reliable indicators of who will
develop complications. Conceivably, the rate of increase of serum ferritin will prove
in the future to be an indicator of potential tissue and organ damage. In the absence
of results from controlled trials, we currently favor proceeding to prophylactic phlebotomy
in those individuals who tolerate and adhere to the regimen.
In those patients with advanced disease who may have cardiac arrhythmias or cardiomyopathy,
there is an increased risk of sudden death with rapid mobilization of iron, most likely
due to the presence of intracellular iron in a relatively toxic, low-molecular-weight
chelate pool of iron. Pharmacological doses of vitamin C accelerate mobilization of
iron to a level that may saturate circulating transferrin, resulting in an increase
in pro-oxidant and/or free radical activity.71 Therefore, supplemental vitamin C should
be avoided by iron-loaded patients, particularly those undergoing phlebotomy. No dietary
adjustments are necessary, because the amount of iron absorption that an individual
can affect with a low-iron diet is small (2-4 mg/day) compared to the amount mobilized
with phlebotomy (250 mg/week). Reports of Vibrio vulnificus have been described in
patients with HH who ingest raw shellfish; these foods should be avoided.72
Advanced cirrhosis is not reversed with iron removal, and the development of decompensated
liver disease is an indication to consider orthotopic liver transplantation (OLT).
In the past, survival of patients with HH who underwent liver transplantation was
lower than in those who underwent liver transplantation for other causes of liver
disease.73,74 Most posttransplantation deaths in patients with HH occurred in the
perioperative period from either cardiac or infection-related72 complications.75 These
complications were probably related to inadequate removal of excess iron stores before
OLT. Currently, survival of patients with HH after OLT is comparable to other patients,76
at least in part because diagnosis and treatment occurs prior to OLT.
Recommendations:
9. Patients with hemochromatosis and iron overload should undergo therapeutic phlebotomy
weekly (as tolerated). (1A) Target levels of phlebotomy should be a ferritin level
of 50-100 μg/L. (1B)
10. In the absence of indicators suggestive of significant liver disease (ALT, AST
elevation), C282Y homozygotes who have an elevated ferritin (but <1000 μg/L) should
proceed to phlebotomy without a liver biopsy. (1B)
11. Patients with end-organ damage due to iron overload should undergo regular phlebotomy
to the same endpoints as indicated above. (1A)
12. During treatment for HH, dietary adjustments are unnecessary. Vitamin C supplements
and iron supplements should be avoided. (1C)
13. Patients with hemochromatosis and iron overload should be monitored for reaccumulation
of iron and undergo maintenance phlebotomy. (1A) Target levels of phlebotomy should
be a ferritin level of 50-100 μg/L. (1B)
14. We recommend treatment by phlebotomy of patients with non-HFE iron overload who
have an elevated HIC. (1B)
Treatment of Secondary Iron Overload
These guidelines have primarily concentrated on the management of HH, but it is reasonable
to review the treatment of noninherited forms of secondary iron overload. The causes
of secondary iron overload are listed in Table 3.
Phlebotomy is useful in certain forms of secondary iron overload (Table 8). Phlebotomy
is clearly indicated in patients with PCT, and results in a reduction in skin manifestations.
Total iron stores rarely exceeds 4-5 g. Secondary iron overload is sometimes seen
in association with chronic hepatitis C, NAFLD, and ALD.77 There is no published evidence
that phlebotomy is of benefit in ALD. In chronic hepatitis C, it has been shown that
phlebotomy therapy reduces elevated ALT levels and achieves a marginal improvement
in histopathology, but has no effect on virologic clearance.78 Currently, phlebotomy
is not recommended for mild secondary iron overload (HIC < 2500 μg/g dry weight) in
chronic hepatitis C. In NAFLD, studies have shown a benefit of therapeutic phlebotomy
with improvement in parameters of insulin resistance and reduction in elevated ALT
levels.79,80 Large-scale studies in patients with NAFLD have been proposed.
In secondary iron overload associated with ineffective erythropoiesis, iron chelation
therapy with parenteral deferoxamine is the treatment of choice. Numerous studies
have documented the efficacy of deferoxamine in preventing the complications of iron
overload in β-thalassemia.81 Recently, deferasirox (Exjade), an orally administered
iron-chelating drug, has been approved in the United States for treatment of secondary
iron overload due to ineffective erythropoiesis. Studies are ongoing regarding its
potential use in HH. However, recent concerns about complications have tempered enthusiasm
for this drug in HH.82 Deferoxamine is usually administered by continuous subcutaneous
infusion using a battery-operated infusion pump at a dose of 40 mg/kg/day for 8-12
hours nightly for 5-7 nights weekly. A total dose of approximately 2 g per 24 hours
usually achieves maximal urinary iron excretion. Chelation therapy to reduce HIC <
15,000 μg/g dry weight significantly reduces the risk of clinical disease.83 The application
of deferoxamine therapy is limited by cost, the need for a parenteral route of therapy,
discomfort, inconvenience, and neurotoxcity. Monitoring iron reduction in patients
with secondary iron overload is challenging. In contrast to HH, where serum ferritin
reliably reflects iron burden during therapy, ferritin levels can be misleading in
secondary iron overload. In some patients, it may be necessary to repeat liver biopsy
to assess the progress of therapy and ensure adequate chelation.84 Monitoring 24-hour
urinary iron excretion is sometimes helpful. By detecting magnetic susceptibility,
a superconducting quantum interference device (SQUID) is capable of measuring HIC
over a wide range, but this is a research technique that is available only in a few
centers worldwide.85 The recent development of certain magnetic resonance imaging
programs has shown promise in providing a noninvasive method to evaluate HIC.86,87
In patients with secondary iron overload, HIC provides an accurate quantitative means
for monitoring iron balance.88
Recommendations:
15. Iron chelation with either deferoxamine mesylate or deferasirox is recommended
in iron overloaded patients with dyserythropoietic syndromes or chronic hemolytic
anemia. (1A)
Surveillance for Hepatocellular Cancer
In patients with HH who present with cirrhosis, the recent AASLD guidelines for HCC
surveillance should be followed.89 These recommendations should be extended to patients
with HH who have cirrhosis, whether they have had phlebotomy to restore normal iron
levels. The relative risk for HCC is approximately 20, with an annual incidence of
3%-4%.89 Patients with HH with advanced fibrosis or cirrhosis should be screened regularly
for HCC as per AASLD guidelines.
General Population Screening
When considering the evidence required to determine whether general population screening
should be performed for the C282Y mutation, a key factor is the clinical penetrance
of C282Y homozygosity. Approximately 30% of C282Y homozygotes do not have phenotypic
expression of excess iron stores in cross-sectional studies (Table 2). Because of
this, from a public policy perspective, general population screening for HH is not
indicated. In a large Norwegian study, 65,238 subjects were screened using TS, and
when it was elevated on two determinations, cases were confirmed by genetic testing
and/or liver biopsy.11 In 147 subjects, liver biopsies were performed and only four
men and none of the women had cirrhosis (2.7% prevalence of cirrhosis). An Australian
population study of 3011 individuals revealed 16 C282Y homozygotes. Of these 16, liver
biopsy was performed in 11 cases with serum ferritin >300 μg/L, of whom three were
identified with advanced fibrosis and one with cirrhosis who had associated ALD (6.3%
prevalence of cirrhosis).90 Other prospective population studies have reached similar
conclusions that the clinical penetrance of C282Y homozygosity is quite low.10,12
This discrepancy between the morbidity seen in referred patients and the lack of morbidity
in screened patients is not unique to HH.
Economic models that have included genetic testing have suggested that population
screening for HH would be effective if only 20% of patients developed life-threatening
complications.91,92 The natural history of untreated HH has been illustrated in the
Copenhagen Heart Study, where patients were followed for 25 years with serial ferritin
testing without an awareness that they were C282Y homozygotes.93 Many patients did
not demonstrate progression of iron overload as measured by serum ferritin, and the
costs of investigating false positive iron tests in a screening program were considered
significant. This has led some to consider that a genetic test should be done first,
followed by measurement of serum ferritin. There have been concerns expressed about
the adverse effects of genetic testing such as genetic discrimination; however, several
studies have demonstrated that this is rarely a valid concern.94 Nonetheless, widespread
population screening for HH is not recommended, whereas more selective screening in
high-risk populations needs further study.5,95
Recommendations:
16. Average risk population screening for HH is not recommended
.93 (
1B
)
Screening for Non–HFE-related HH
The term “non–HFE-related HH” refers to several genetically distinct forms of inherited
iron overload affecting individuals without HFE mutations.17 Several of the genes
involved are hemojuvelin (HJV), ferroportin (SLC40A1), transferrin receptor 2 (TFR2),
and hepcidin (HAMP). The non-HFE forms of inherited iron overload are rare, accounting
for <5% of cases encountered, and genetic testing is largely unavailable except in
research laboratories.
Screening for non–HFE-related HH is not recommended.