Glossary

Terms Related to Hereditary Hemochromatosis

Autosomal

Humans have 23 pairs of chromosomes. Chromosomes 1-22 have nothing to do with sexual characteristics and are called ‘autosomal’ chromosomes (or autosomes).

C282Y Mutation

Refers to the most common mutation of the HFE gene. The C282Y mutation results in a change in the amino acid in the protein produced, and affects how the protein ‘folds,’ thereby limiting its ability to perform its task.

Carrier

In the case of hemochromatosis, a person who carries a mutation in one of the two copies of the HFE gene on chromosome 6 (versus affected persons have mutations in both copies of the HFE gene).

Chromosome

Thread-like structures, contained inside the middle (nucleus) of all our cells, which houses DNA — our genetic information. Human cells have 23 pairs of chromosomes; we inherit one of each pair from our mother and father. 22 pairs are autosomes and the 23rd pair is the sex chromosomes (X and Y).

Compound Heterozygotes

Individuals who inherit two different mutated versions of the HFE gene, one on each of their chromosomes. Compound heterozygotes usually have a C282Y mutation in one HFE gene copy, and a H63D mutation in the second HFE gene copy.

DNA

Short for deoxyribonucleic acid, DNA is the molecule that encodes all of our genetic information.

Ferritin

A protein that stores iron. High ferritin levels in the blood can be one indication of hemochromatosis.

Gene

A specific portion of DNA that contains instructions for making a specific functional product called a protein.

H63D Mutation

A mutation in the HFE gene, which (like the C282Y mutation) results in a change in the amino acid in the protein produced, and affects how the protein ‘folds,’ thereby limiting its ability to perform its task.

HFE Gene

The gene on chromosome 6 that encodes the HFE protein. People with Type 1 hereditary hemochromatosis have abnormal HFE proteins due to mutations in the HFE gene.

HHC

Abbreviation for hereditary hemochromatosis.

Heterozygotes

The technical term for a carrier, describing individuals who have inherited one normal and one mutated version of the same gene, one on each of their chromosomes.

Homozygotes

Individuals who have inherited two identical mutations in a gene, one on each of their chromosomes.

Phlebotomy

Bloodletting, the common treatment for hemochromatosis.

Transferrin

A protein that circulates in the bloodstream and binds to iron thus “ferrying” iron to other parts of the body. Transferrin is normally 30% bound to iron.