From OMIMHereditary hemochromatosis is an autosomal recessive disorder of iron metabolism wherein the body accumulates excess iron (summary by Feder et al., 1996). Excess iron is deposited in a variety of organs leading to their failure, and resulting in serious illnesses including cirrhosis, hepatomas, diabetes, cardiomyopathy, arthritis, and hypogonadotropic hypogonadism. Severe effects of the disease usually do not appear until after decades of progressive iron loading. Removal of excess iron by therapeutic phlebotomy decreases morbidity and mortality if instituted early in the course of the disease. Classic hemochromatosis (HFE) is most often caused by mutation in a gene designated HFE on chromosome 6p21.3.
Adams and Barton (2007) reviewed the clinical features, pathophysiology, and management of hemochromatosis.
Genetic Heterogeneity of Hemochromatosis
At least 4 additional iron overload disorders labeled hemochromatosis have been identified on the basis of clinical, biochemical, and genetic characteristics. Juvenile hemochromatosis, or hemochromatosis type 2 (HFE2), is autosomal recessive and is divided into 2 forms: HFE2A (602390), caused by mutation in the HJV gene (608374) on chromosome 1q21, and HFE2B (613313), caused by mutation in the HAMP gene (606464) on chromosome 19q13. Hemochromatosis type 3 (HFE3; 604250), an autosomal recessive disorder, is caused by mutation in the TFR2 gene (604720) on chromosome 7q22. Hemochromatosis type 4 (HFE4; 606069), an autosomal dominant disorder, is caused by mutation in the SLC40A1 gene (604653) on chromosome 2q32. Hemochromatosis type 5 (HFE5; 615517) is caused by mutation in the FTH1 gene (134770) on chromosome 11q12.
http://www.omim.org/entry/235200 From MedlinePlus GeneticsHereditary hemochromatosis is a disorder that causes the body to absorb too much iron from the diet. The excess iron is stored in the body's tissues and organs, particularly the skin, heart, liver, pancreas, and joints. Because humans cannot increase the excretion of iron, excess iron can overload and eventually damage tissues and organs. For this reason, hereditary hemochromatosis is also called an iron overload disorder.
Early symptoms of hereditary hemochromatosis may include extreme tiredness (fatigue), joint pain, abdominal pain, weight loss, and loss of sex drive. As the condition worsens, affected individuals may develop arthritis, liver disease (cirrhosis) or liver cancer, diabetes, heart abnormalities, or skin discoloration. The appearance and severity of symptoms can be affected by environmental and lifestyle factors such as the amount of iron in the diet, alcohol use, and infections.
There are four types of hereditary hemochromatosis, which are classified depending on the age of onset and other factors such as genetic cause and mode of inheritance.
Type 1, the most common form of the disorder, and type 4 (also called ferroportin disease) begin in adulthood. Men with type 1 or type 4 hemochromatosis typically develop symptoms between the ages of 40 and 60, and women usually develop symptoms after menopause.
Type 2 hemochromatosis is known as a juvenile-onset disorder because symptoms often begin in childhood. By age 20, iron accumulation causes decreased or absent secretion of sex hormones. Affected females usually begin menstruation normally but menses stop after a few years. Males may experience delayed puberty or symptoms related to a shortage of sex hormones. If type 2 hemochromatosis is untreated, potentially fatal heart disease becomes evident by age 30.
The onset of type 3 hemochromatosis is usually intermediate between types 1 and 2 with symptoms generally beginning before age 30.
https://medlineplus.gov/genetics/condition/hereditary-hemochromatosis