Gene /protein name-huntingtin
HTT or HD
The HTT mutation that causes Huntington disease involves a 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. In people with Huntington disease, the CAG segment is repeated 36 to more than 120 times.

Occurs on fourth chromosome

Disorder Type
Gene Mutation
Autosomal Dominant
Due to Trionucleotide repeat disorder

Although the exact function of huntingtin is unknown, it appears to play an important role in nerve cells (neurons) in the brain and is essential for normal development before birth.