|http://ghr.nlm.nih.gov/ A service of the U.S. National Library of Medicine®|
The official name of this gene is “ataxin 1.”
ATXN1 is the gene's official symbol. The ATXN1 gene is also known by other names, listed below.
The ATXN1 gene provides instructions for making a protein called ataxin-1. This protein is found throughout the body, but its function is unknown. Within cells, ataxin-1 is located in the nucleus. Researchers believe that ataxin-1 may be involved in regulating various aspects of producing proteins, including the first stage of protein production (transcription) and processing RNA, a chemical cousin of DNA.
One region of the ATXN1 gene contains 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 4 to 39 times within the gene.
Spinocerebellar ataxia type 1 (SCA1) is a condition characterized by progressive problems with movement. SCA1 results from a mutation in the ATXN1 gene known as a trinucleotide repeat expansion. This mutation increases the length of the repeated CAG segment in the ATXN1 gene. People with SCA1 have from 40 to more than 80 CAG repeats in most cells.
The expanded CAG segment leads to the production of an abnormally long version of the ataxin-1 protein that folds into the wrong 3-dimensional shape. This abnormal protein clusters with other proteins to form clumps (aggregates) within the nucleus of cells. These aggregates prevent the ataxin-1 protein from functioning normally, which damages cells. For reasons that are unclear, aggregates of ataxin-1 are found only in the brain and spinal cord (central nervous system). Certain brain cells called Purkinje cells seem to be particularly sensitive to the accumulation of these aggregates. Purkinje cells are located in the part of the brain that coordinates movement (cerebellum) and are involved in chemical signaling between nerve cells (neurons). The accumulation of protein aggregates in the cells of the central nervous system, particularly in Purkinje cells, leads to cell death. Over time, the loss of these cells causes the movement problems characteristic of SCA1.
Cytogenetic Location: 6p23
Molecular Location on chromosome 6: base pairs 16,299,342 to 16,761,720
The ATXN1 gene is located on the short (p) arm of chromosome 6 at position 23.
More precisely, the ATXN1 gene is located from base pair 16,299,342 to base pair 16,761,720 on chromosome 6.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about ATXN1 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
adenine ; ataxia ; cell ; central nervous system ; cerebellum ; cytosine ; DNA ; gene ; guanine ; mutation ; nervous system ; nucleus ; protein ; Purkinje cells ; RNA ; stage ; transcription ; trinucleotide repeat
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.