Hemochromatosis type 2B is the less common form of juvenile hemochromatosis. It is a disorder caused by a change (mutation) in the HAMP gene. This change causes the body to absorb too much iron as it digests food. This excess iron is stored in several of the body’s organs and can eventually cause cancer, diabetes, irregular heartbeats (arrhythmia), and permanent scaring of the liver (cirrhosis). There are several types of hemochromatosis. Type 2B is an autosomal recessive disorder, meaning that if you inherit the changed gene from both of your parents, then you will have the disorder (genes come in pairs, one copy from each parent). Parents with only one changed copy of the HAMP gene are known as carriers. Carriers usually do not have symptoms of the disorders they carry, but in this case slightly higher body iron levels are common.
Symptoms may begin in childhood but may not be noticed until age 20. Type 2B most often affects Caucasians but is equally common in men and women. Common symptoms include joint pain, fatigue, weakness, bronzed skin, and diabetes. Type 2B also causes heart disease (cardiomyopathy) and issues with reproductive organs (hypogonadism) that can lead to infertility. The high levels of iron in the blood can lead to high transferrin saturation, high levels of a protein called ferritin, and high liver iron content.
For many people, the only symptom is a high level of iron in the blood, which can make forming a diagnosis challenging. Two types of blood tests may be done to diagnose the disorder. To confirm the diagnosis, other tests may include an MRI and liver biopsy. Treatments are available to manage the disorder. Research is ongoing, so talk with your doctor(s) about the most current treatment options. A genetic counselor can help you understand how the disorder runs in families. Support groups are also a good source of information and can connect you with others living with hemochromatosis.