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Reviewed October 2008
What is the official name of the HTT gene?
The official name of this gene is “huntingtin.”
HTT is the gene's official symbol. The HTT gene is also known by other names, listed below.
Read more about gene names and symbols on the About page.
What is the normal function of the HTT gene?
The HTT gene provides instructions for making a protein called huntingtin. Although the exact function of this protein is unknown, it appears to play an important role in nerve cells (neurons) in the brain and is essential for normal development before birth. Huntingtin is found in many of the body's tissues, with the highest levels of activity in the brain. Within cells, this protein may be involved in chemical signaling, transporting materials, attaching (binding) to proteins and other structures, and protecting the cell from self-destruction (apoptosis).
One region of the HTT gene contains a particular DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row. Normally, the CAG segment is repeated 10 to 35 times within the gene.
Does the HTT gene share characteristics with other genes?
The HTT gene belongs to a family of genes called endogenous ligands (endogenous ligands).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.
How are changes in the HTT gene related to health conditions?
Where is the HTT gene located?
Cytogenetic Location: 4p16.3
Molecular Location on chromosome 4: base pairs 3,074,510 to 3,243,960
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The HTT gene is located on the short (p) arm of chromosome 4 at position 16.3.
More precisely, the HTT gene is located from base pair 3,074,510 to base pair 3,243,960 on chromosome 4.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about HTT?
You and your healthcare professional may find the following resources about HTT helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
What other names do people use for the HTT gene or gene products?
See How are genetic conditions and genes named? in the Handbook.
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding HTT?
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (14 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.