Hemo-chroma-what? Understanding Hereditary Hemochromatosis
Hemochromatosis. It’s a big word. But medical words have a way of seeming intimidating and keeping us from understanding important things. So we’re going to refer to ‘hereditary hemochromatosis’ as ‘HH’, and raise some awareness about what it is — because it’s HH awareness month!
What is Hereditary Hemochromatosis?
Hereditary hemochromatosis is a genetic condition that causes the body to absorb excessive amounts of iron from the diet. The extra iron is stored in the body’s tissues and organs — especially the skin, liver, heart, pancreas, and joints. Iron-excretion occurs at a constant rate and, without the ability to increase excretion, the body eventually gets overloaded with excess iron that can damage tissues and organs.
Symptoms include fatigue, joint and abdominal pain, weight loss, and loss of sex drive. As the condition progresses, individuals may develop arthritis, liver disease (cirrhosis or cancer), diabetes, or heart abnormalities.
The Genetics of HH
HH comes in four types, three of which are inherited in a recessive manner and one in a dominant manner:
Type 1 (most common) — caused by mutations in the HFE gene; symptoms begin in adulthood (40–60 in men, post-menopause in women)
Type 2 (juvenile-onset) — caused by mutations in HJV or HAMP; iron accumulation begins in childhood, potentially causing fatal heart disease by age 30
Type 3 — caused by mutations in TFR2; symptoms typically begin before age 30
Type 4 (dominant inheritance) — caused by mutations in SLC40A1; similar presentation to Type 1
Understanding Recessive vs. Dominant Inheritance
For recessive conditions, you need two non-working copies of a gene (one from each parent) to develop the condition. If both parents are carriers, each child has a 25% chance of inheriting both non-working copies. For dominant conditions, a single non-working copy is enough to cause the condition — and each child of an affected parent has a 50% chance of inheriting it.
Diagnosis and Treatment
Genetic testing can confirm a diagnosis of HH and inform appropriate clinical management to prevent secondary complications including liver disease and rheumatoid arthritis. Therapeutic phlebotomy (removal of blood) is effective treatment — and if an individual meets routine criteria for blood donation, their blood can be used to save a life.
Know Your Genetic Risk for Iron Overload Conditions
Genomepatri by MapmyGenome screens your genetic predisposition to hereditary conditions including iron metabolism disorders — enabling early detection and proactive management before organ damage occurs.
