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ATN1 gene

atrophin 1

Normal Function

The ATN1 gene provides instructions for making a protein called atrophin 1. Although the exact function of this protein is unknown, it appears to play an important role in nerve cells (neurons) in many areas of the brain. Researchers speculate that atrophin 1 may act as a transcriptional co-repressor. A transcriptional co-repressor is a protein that interacts with other DNA-binding proteins to suppress the activity of certain genes, although it cannot attach (bind) to DNA by itself.

One region of the ATN1 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. In most people, the number of CAG repeats in the ATN1 gene ranges from 6 to 35.

Health Conditions Related to Genetic Changes

Dentatorubral-pallidoluysian atrophy

Dentatorubral-pallidoluysian atrophy (DRPLA) is a progressive brain disorder that causes involuntary movements, mental and emotional problems, and a decline in thinking ability. DRPLA results from an increased number of copies (expansion) of the CAG trinucleotide repeat in the ATN1 gene. Specifically, the CAG segment is repeated at least 48 times, and the repeat region may be two or three times its usual length. The extended CAG region changes the structure of atrophin 1 and how the protein interacts with other proteins to control gene function. This altered protein accumulates in neurons and interferes with normal cell functions. The dysfunction and eventual death of these neurons lead to involuntary movements, intellectual decline, and the other characteristic features of DRPLA.

More About This Health Condition

Other disorders

Variants (also called mutations) in the ATN1 gene can cause a very rare condition called congenital hypotonia, epilepsy, developmental delay, and digital anomalies (CHEDDA) syndrome. Individuals with this condition have severe intellectual and developmental delays. They also have a very limited or no ability to talk and cannot walk. People with CHEDDA can have weak muscle tone (hypotonia), recurring seizures (epilepsy), vision and hearing problems, distinctive facial features, and skeletal abnormalities. Many affected individuals have brain malformations. 

The ATN1 gene variants that cause CHEDDA syndrome occur in one of the two copies of the gene in each cell and lead to a change in single protein building blocks (amino acids) in atrophin 1. As a result, the protein is altered and cannot function normally, though it is unclear how these changes lead to the specific features of CHEDDA syndrome. 

Other Names for This Gene

  • atrophin-1
  • B37
  • D12S755E
  • dentatorubral-pallidoluysian atrophy protein
  • NOD

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Chaudhry A, Anthanasiou-Fragkouli A, Houlden H. DRPLA: understanding the natural history and developing biomarkers to accelerate therapeutic trials in a globally rare repeat expansion disorder. J Neurol. 2021 Aug;268(8):3031-3041. doi: 10.1007/s00415-020-10218-6. Epub 2020 Oct 26. Erratum In: J Neurol. 2021 Aug;268(8):3042. doi: 10.1007/s00415-021-10644-0. Citation on PubMed
  • Katsuno M, Banno H, Suzuki K, Takeuchi Y, Kawashima M, Tanaka F, Adachi H, Sobue G. Molecular genetics and biomarkers of polyglutamine diseases. Curr Mol Med. 2008 May;8(3):221-34. doi: 10.2174/156652408784221298. Citation on PubMed
  • Nagafuchi S, Yanagisawa H, Ohsaki E, Shirayama T, Tadokoro K, Inoue T, Yamada M. Structure and expression of the gene responsible for the triplet repeat disorder, dentatorubral and pallidoluysian atrophy (DRPLA). Nat Genet. 1994 Oct;8(2):177-82. doi: 10.1038/ng1094-177. Citation on PubMed
  • Nowak B, Kozlowska E, Pawlik W, Fiszer A. Atrophin-1 Function and Dysfunction in Dentatorubral-Pallidoluysian Atrophy. Mov Disord. 2023 Apr;38(4):526-536. doi: 10.1002/mds.29355. Epub 2023 Feb 21. Citation on PubMed
  • Prades S PhD, Melo de Gusmao C MD, Grimaldi S MD, Shiloh-Malawsky Y MD, Felton T MS, CGC, Houlden H MD, PhD. DRPLA. 1999 Aug 6 [updated 2023 Sep 21]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from Citation on PubMed
  • Whitton C, Palmer E, Alkuraya F. ATN1-Related Neurodevelopmental Disorder. 2022 Aug 25. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from Citation on PubMed
  • Wood JD, Nucifora FC Jr, Duan K, Zhang C, Wang J, Kim Y, Schilling G, Sacchi N, Liu JM, Ross CA. Atrophin-1, the dentato-rubral and pallido-luysian atrophy gene product, interacts with ETO/MTG8 in the nuclear matrix and represses transcription. J Cell Biol. 2000 Sep 4;150(5):939-48. doi: 10.1083/jcb.150.5.939. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.