Hereditary hemochromatosis

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Hereditary 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.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in several genes can cause hereditary hemochromatosis. Type 1 hemochromatosis results from mutations in the HFE gene, and type 2 hemochromatosis results from mutations in either the HJV or HAMP gene. Mutations in the TFR2 gene cause type 3 hemochromatosis, and mutations in the SLC40A1 gene cause type 4 hemochromatosis.

The proteins produced from these genes play important roles in regulating the absorption, transport, and storage of iron in the body. Mutations in any of these genes impair the control of the intestine's absorption of iron from foods during digestion and alter the distribution of iron to other parts of the body. As a result, iron accumulates in tissues and organs, which can disrupt their normal functions.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Types 1, 2, and 3 hemochromatosis are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene but do not show signs and symptoms of the condition.

Type 4 hemochromatosis is distinguished by its autosomal dominant inheritance pattern. With this type of inheritance, one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Type 1 hemochromatosis is one of the most common genetic disorders in the United States, affecting about 1 million people. It most often affects people of Northern European descent. The other types of hemochromatosis are considered rare and have been studied in only a small number of families worldwide.

Which doctor should you see?

The suggested department for discussing Hereditary hemochromatosis is Hepatology, with a hepatologist / gastroenterologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What is known about the cause and extent of liver involvement?
• Which medicines, supplements or exposures should be reviewed?
• What follow-up is appropriate for the specific diagnosis and stage?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.