Rare hereditary hemochromatosis

Rare hereditary hemochromatosis (Orphanet code 220489) encompasses the less common genetic forms of hereditary hemochromatosis beyond the classic HFE-related (type 1) form. These rare subtypes include juvenile hemochromatosis (type 2A caused by HJV/hemojuvelin mutations and type 2B caused by HAMP/hepcidin mutations), transferrin receptor 2-related hemochromatosis (type 3, caused by TFR2 mutations), and ferroportin disease (type 4, caused by SLC40A1 mutations). All forms are characterized by excessive iron absorption from the diet, leading to progressive iron overload in multiple organ systems. The liver, heart, pancreas, endocrine glands, joints, and skin are primarily affected. Clinical features vary by subtype but commonly include liver disease (hepatomegaly, fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma), cardiomyopathy, diabetes mellitus, hypogonadotropic hypogonadism, arthropathy, skin hyperpigmentation (bronze discoloration), and fatigue. Juvenile forms (type 2) tend to present earlier in life, often before age 30, with more severe cardiac and endocrine involvement, whereas type 3 resembles classic hemochromatosis in its clinical course. Ferroportin disease (type 4) has a distinct pathophysiology and may present with predominant macrophage iron loading and variable tolerance to phlebotomy. Diagnosis involves elevated serum ferritin and transferrin saturation, confirmed by genetic testing. Treatment primarily consists of therapeutic phlebotomy (regular blood removal) to reduce iron stores and prevent organ damage. In patients who cannot tolerate phlebotomy, iron chelation therapy may be used. Early diagnosis and treatment can prevent irreversible organ damage and significantly improve prognosis. Dietary modifications, including avoidance of iron supplements and limiting alcohol consumption, are also recommended as supportive measures.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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