Hereditary Hemochromatosis

There are 4 types of hereditary hemochromatosis, types 1 through 4, depending on the gene that is mutated.

Other much rarer genetic disorders can cause hepatic iron overload, but the clinical picture is usually dominated by symptoms and signs due to failure of other organs (eg, anemia in hypotransferrinemia or atransferrinemia, or neurologic defects in aceruloplasminemia).

Although these types vary markedly in age of onset, clinical consequences of iron overload are the same in all types.

The clinical consequences of iron overload tend to be similar regardless of the etiology and pathophysiology of the overload.

Historically, experts believed that symptoms did not develop until significant organ damage had occurred. However, organ damage is slow and subtle, and fatigue and nonspecific systemic symptoms and signs often occur early. For example, liver dysfunction can manifest insidiously with fatigue, right upper quadrant abdominal pain, and hepatomegaly. Laboratory abnormalities of iron overload and hepatitis usually precede symptoms.

In type 1 hereditary (HFE) hemochromatosis, symptoms relate to the organs with the largest iron deposits (see table Common Manifestations of Hereditary Hemochromatosis). In men, the initial symptoms may be hypogonadism and erectile dysfunction caused by gonadal iron deposition. Glucose intolerance or diabetes mellitus is another common initial presentation. Some patients present with hypothyroidism.

Liver disease is the most common complication and may progress to cirrhosis; 20 to 30% of patients with cirrhosis develop hepatocellular carcinoma. Liver disease is the most common cause of death. Elevated liver enzymes are one of the most common laboratory abnormalities in patients with type 1 hemochromatosis.

Cardiomyopathy with heart failure is the 2nd most common fatal complication. Hyperpigmentation (bronze diabetes) and porphyria cutanea tarda are common, as is symptomatic arthropathy in the hands.

In type 2 disease, symptoms and signs include progressive hepatomegaly and hypogonadotropic hypogonadism.

In type 3 disease, symptoms and signs are similar to type 1 hereditary (HFE) hemochromatosis.

In type 4 disease manifests in the first decade of life as increased serum ferritin levels with low or normal transferrin saturation; progressive saturation of transferrin occurs when patients are in their 20s and 30s. Clinical manifestations are milder than in type 1 disease, with modest liver disease and mild anemia.

Symptoms and signs may be nonspecific, subtle, and of gradual onset, so that index of suspicion should be high. Primary hemochromatosis should be suspected when typical manifestations, particularly combinations of such manifestations, remain unexplained after routine evaluation. Family history of hemochromatosis, cirrhosis, or hepatocellular carcinoma is a more specific clue. All patients with chronic liver disease should be evaluated for iron overload, regardless of race or ethnicity

Serum ferritin measurement is the simplest and most direct initial test. Elevated levels (> 200 ng/mL [> 200 mcg/L] in women or > 250 ng/mL [> 250 mcg/L] in men) are usually present in hereditary hemochromatosis but can result from other abnormalities, such as inflammatory liver disorders (eg, chronic viral hepatitis, nonalcoholic fatty liver disease, alcoholic liver disease), cancer, certain systemic inflammatory disorders (eg, rheumatoid arthritis, hemophagocytic lymphohistiocytosis), or obesity. Further testing is done if ferritin level is abnormal; testing includes fasting serum iron (usually > 300 mg/dL [> 53.7 mcmol/L]) and iron binding capacity (transferrin saturation; levels usually > 50%). A transferrin saturation of < 45% has a negative predictive value of 97% for iron overload.

In type 2 disease, ferritin levels are >1000 ng/mL (> 1000 mcg/L), and transferrin saturation is >90%.

In transferrin or ceruloplasmin deficiency, serum transferrin (ie, iron-binding capacity) and ceruloplasmin levels are profoundly low or undetectable.

Gene assay is diagnostic of hereditary hemochromatosis caused by HFE gene mutations. About 70% of patients with C282Y homozygous mutations of the HFE gene have an elevated ferritin level, but only about 10% of these patients have evidence of organ dysfunction. Clinically significant iron overload is even less common in patients with heterozygous mutations of the HFE gene (ie, C282Y/H63D). Hemochromatosis types 2 to 4 are suspected in the less common instances in which ferritin and iron blood tests indicate iron overload and genetic testing is negative for the HFE gene mutation, particularly in younger patients. Confirmation of these diagnoses by genetic testing is not routinely available.

When the diagnosis is confirmed, the liver must be tested for fibrosis and cirrhosis. Up to 80% of patients with cirrhosis and a homozygous C282Y mutation will have a ferritin of > 1000 ng/mL, elevated AST (aspartate transaminase) and ALT (alanine transaminase), and platelet count < 200 × 10³ /mcL (< 200 × 10⁹/L). Because the presence of cirrhosis affects prognosis, when the ferritin is > 1000 ng/mL, liver biopsy is commonly done and tissue iron content is measured (when available). Liver biopsy is also recommended in patients with serologic evidence of iron overload but negative genetic evaluation. MRI with noncontrast MR elastography (MRE), a noninvasive alternative for estimating hepatic iron content and hepatic fibrosis, is becoming increasingly accurate.

Screening is required for first-degree relatives of people with hereditary hemochromatosis by measuring serum ferritin levels and testing for the C282Y and H63D mutations in the HFE gene.

Treatment is indicated for patients with clinical manifestations, elevated serum ferritin levels (particularly levels > 1000 ng/mL [> 1000 mcg/L]), or elevated transferrin saturation. Asymptomatic patients need only periodic (eg, yearly) clinical evaluation and measurement of serum iron, ferritin, transferrin saturation, and liver enzymes.

Phlebotomy is the simplest and most effective method to remove excess iron. It delays progression of fibrosis to cirrhosis, sometimes even reversing cirrhotic changes, and prolongs survival, but it does not prevent hepatocellular carcinoma. About 500 mL of blood (about 250 mg of iron) is removed weekly or biweekly (every other week) until serum ferritin levels reach 50 to 100 ng/mL. Weekly or biweekly phlebotomy may be needed for many months (eg, if 250 mg of iron are removed per week, 40 weeks will be required to remove 10 g of iron). When iron levels are normal, phlebotomies can be intermittent to maintain ferritin between 50 and 100 ng/mL.

Diabetes mellitus, cardiomyopathy, erectile dysfunction, and other secondary manifestations are treated as indicated. Patients with advanced fibrosis or cirrhosis due to iron overload should be screened for hepatocellular carcinoma every 6 months with a liver ultrasound.

Patients should follow a balanced diet; it is not necessary to restrict consumption of iron-containing foods (eg, red meat, liver). Alcohol should be consumed only in moderation because it can increase iron absorption and, in high amounts, increases the risk of cirrhosis. Vitamin C supplements should be avoided because they increase the absorption of iron in the duodenum.

In patients with type 4 disease, tolerance to vigorous phlebotomy is poor; serial monitoring of hemoglobin level and transferrin saturation is required.

Treatment of transferrin deficiency and ceruloplasmin deficiency is experimental; eg, iron chelators may be better tolerated than phlebotomy because patients typically have anemia.