Hemochromatosis type 4 is a disorder caused by a change (mutation) in the SLC40A1 gene. This change causes the body to absorb too much iron as it digests food. The excess iron is stored in several of the body’s organs and can eventually cause cancer, diabetes, irregular heartbeats (arrhythmia), and permanent scarring of the liver (cirrhosis). There are several types of hemochromatosis, but Type 4 is the only autosomal dominant form. Autosomal dominant means that an individual only needs to inherit one changed SCL40A1 gene to have the disorder (genes come in pairs, one copy from each parent). If you have Type 4, you have a 50% chance of passing it down to each of your children. However, some people with Type 4 do not ever have serious symptoms. Those who show symptoms have good chances of leading a normal life if treatment begins early.
Common symptoms include joint pain, fatigue, weakness, bronzed skin, diabetes, heart failure, and issues with the ovaries or testes (hypogonadism). In men, hemochromatosis may cause loss of sex drive (low libido) or impotence. Symptoms often appear in midlife, usually between the ages of 40 to 60. Women who develop the disorder have usually already gone through menopause.
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.