Nonetheless, in minor frequency, there are 4 additional disorders of primary iron overload: juvenile hemochromatosis (JH) or type 2 hemochromatosis, which is divided into 2 forms: type 2A JH, caused by mutations in the HJV gene on chromosome 1q21, and type 2B JH, caused by mutations in the HAMP gene on chromosome 19q13. The gene discussed is HJV; the disease is hemochromatosis type 2.