SCA3 ATXN3

Disease ID
SCA3, MJD
Gene ID
ATXN3
Updated
Jan 23, 2026
v2.14.0
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Disease

SCA
Name
Spinocerebellar ataxia type 3/Machado-Joseph disease
Inheritance
Autosomal dominant
Description
Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease, is the most common subtype of type 1 autosomal dominant cerebellar ataxia (ADCA type 1), a neurodegenerative disorder, and is characterized by ataxia, external progressive ophthalmoplegia, and other neurological manifestations1 . Research suggests that length of ATXN2 expansions may affect the phenotype of SCA32 .
Prevalence
2.1 100,000
1-5/100,0003 . Most prevalent SCA subtype4 . Found worldwide across ancestries/ethnicities5 .
Age of Onset(Typical)Years3  7310  49
Age of Onset Details
Typical: 10-495 ; 36 - 735,7 .

Locus

Details
Benign alleles range from 11-44 repeats8 , with intermediate alleles (45-59) associated with incomplete penetrance and non-classic phenotypes5 . The threshold between incomplete and full penetrance is unclear, but presumed to occur at ~60 repeats5,8 . The interruption CAA has been observed9 ; AAG is present in hg38 reference sequence. The APOE ε4 allele appears to act as a disease modifier10 ; GLS expansions may also function as disease modifiers11 .
Mechanism
GoF
Polyglutamine expansion leading to gain of function; aggregated and mislocalized proteins in neurons12,5 .
Year
199413
Location in Gene
Coding Exon 10
Gene Strand

Alleles

Ref. Motif
CTG
Pathogenic (ref.)
CTG
Pathogenic (gene)
AGC
BenignIntermediatePathogenicUnits11  4445  5960  87

gnomAD

References

Direct supporting references for info on this page.

1
Ontology Lookup Service (OLS)
mondo:0007182
2
Influence of ATXN2 intermediate CAG repeats, 9bp duplication and alternative splicing on SCA3 pathogenesis.
Marilena,Lauerer, Jennifer,Faber, Nicolas,Casadei, Magda M,Santana, Georg,Auburger, Michaela,Pogoda, Jakob,Admard, Lea,Kaupp, Patricia Laura,Kos, Mafalda,Raposo, Manuela,Lima, Luis Pereira,de Almeida, Hector,Garcia-Moreno, Paola,Giunti, Jeroen,de Vries, Bart P,van de Warrenburg, Judith,van Gaalen, Marcus,Grobe-Einsler, Berkan,Koyak, Kathrin,Reetz, Friedrich,Erdlenbruch, Heike,Jacobi, Jon,Infante, Holger,Hengel, Ludger,Schöls, Thomas,Klockgether, Olaf,Rieß, Jeannette,Hübener-Schmid
Acta neuropathologica communications · 2025-07-19
pmid:40684213
3
Profiling of Short-Tandem-Repeat Disease Alleles in 12,632 Human Whole Genomes.
Haibao,Tang, Ewen F,Kirkness, Christoph,Lippert, William H,Biggs, Martin,Fabani, Ernesto,Guzman, Smriti,Ramakrishnan, Victor,Lavrenko, Boyko,Kakaradov, Claire,Hou, Barry,Hicks, David,Heckerman, Franz J,Och, C Thomas,Caskey, J Craig,Venter, Amalio,Telenti
American journal of human genetics · 2017-11-02
pmid:29100084
4
Spinocerebellar Ataxia
Jenish,Bhandari, Pawan K.,Thada, Debopam,Samanta
StatPearls · 2025-01-01
genereviews:NBK557816
5
Spinocerebellar Ataxia Type 3
Henry,Paulson, Vikram,Shakkottai
GeneReviews® · 1993-01-01
genereviews:NBK1196
6
Analysis of Short Tandem Repeat Expansions in a Cohort of 12,496 Exomes from Patients with Neurological Diseases Reveals Variable Genotyping Rate Dependent on Exome Capture Kits.
Clarissa,Rocca, David,Murphy, Chris,Clarkson, Matteo,Zanovello, Delia,Gagliardi, Queen Square,Genomics, Rauan,Kaiyrzhanov, Javeria,Alvi, Reza,Maroofian, Stephanie,Efthymiou, Tipu,Sultan, Jana,Vandrovcova, James,Polke, Robyn,Labrum, Henry,Houlden, Arianna,Tucci
Genes · 2025-01-28
pmid:40004498
7
Mitochondrial DNA haplogroups and age at onset of Machado-Joseph disease/spinocerebellar ataxia type 3: a study in patients from multiple populations.
A,Ramos, M,Planchat, A R,Vieira Melo, M,Raposo, U,Shamim, V,Suroliya, A K,Srivastava, M,Faruq, H,Morino, R,Ohsawa, H,Kawakami, L,Bannach Jardim, M L,Saraiva-Pereira, J,Vasconcelos, C,Santos, M,Lima
European journal of neurology · 2018-12-07
pmid:30414314
8
The Frequency of Intermediate Alleles in Patients with Cerebellar Phenotypes.
Elena,Capacci, Silvia,Bagnoli, Giulia,Giacomucci, Costanza Maria,Rapillo, Alessandra,Govoni, Valentina,Bessi, Cristina,Polito, Irene,Giotti, Alice,Brogi, Elisabetta,Pelo, Sandro,Sorbi, Benedetta,Nacmias, Camilla,Ferrari
Cerebellum (London, England) · 2023-10-31
pmid:37906407
9
Comprehensive genetic diagnosis of tandem repeat expansion disorders with programmable targeted nanopore sequencing.
Igor,Stevanovski, Sanjog R,Chintalaphani, Hasindu,Gamaarachchi, James M,Ferguson, Sandy S,Pineda, Carolin K,Scriba, Michel,Tchan, Victor,Fung, Karl,Ng, Andrea,Cortese, Henry,Houlden, Carol,Dobson-Stone, Lauren,Fitzpatrick, Glenda,Halliday, Gianina,Ravenscroft, Mark R,Davis, Nigel G,Laing, Avi,Fellner, Marina,Kennerson, Kishore R,Kumar, Ira W,Deveson
Science advances · 2022-03-04
pmid:35245110
10
Apolipoprotein E epsilon4 allele is associated with better performance language and visual memory in spinocerebellar ataxia type 3.
Xuanyu,Chen, Kunxin,Lin, Zhixian,Ye, Liangliang,Qiu, Yusen,Qiu, Ruying,Yuan, Xintong,Yu, Chunyu,Huang, Bi,Cheng, Wei,Lin, Tianmin,Lai, Wanjin,Chen, Ning,Wang, Shirui,Gan, Qiuni,Su, Ying,Fu
European journal of neurology · 2025-01-01
pmid:39731318
11
Genetic Analysis of GCA Repeats in the GLS Gene: Implications for Undiagnosed Ataxia and Spinocerebellar Ataxia 3 in Mainland China.
Lijing,Lei, Linliu,Peng, Linlin,Wan, Zhao,Chen, Chunrong,Wang, Huirong,Peng, Rong,Qiu, Beisha,Tang, Hong,Jiang
Movement disorders : official journal of the Movement Disorder Society · 2024-12-19
pmid:39699045
12
Clinical and neuroimaging review of triplet repeat diseases.
Ryo,Kurokawa, Mariko,Kurokawa, Akihiko,Mitsutake, Moto,Nakaya, Akira,Baba, Yasuhiro,Nakata, Toshio,Moritani, Osamu,Abe
Japanese journal of radiology · 2022-09-28
pmid:36169768
13
CAG expansions in a novel gene for Machado-Joseph disease at chromosome 14q32.1.
Y,Kawaguchi, T,Okamoto, M,Taniwaki, M,Aizawa, M,Inoue, S,Katayama, H,Kawakami, S,Nakamura, M,Nishimura, I,Akiguchi
Nature genetics · 1994-11-01
pmid:7874163

Additional Literature

Additional literature related to this locus.

Raw PubMed search results
(All PubMed results returned by searching for this gene, tandem repeats, and disease, in medline format)

Valosin-Containing Protein as a therapeutic target in CAG repeat-driven Spinocerebellar ataxias: Integrative transcriptomic and computational insights.
Surbhi,Singh, Deepika,Joshi, Janki,Makani, Suchitra,Singh, Janhavi,Yadav, Shraddha,Chaurasiya, Chandmayee,Mohanty, Anand,Kumar, Royana,Singh
Computational biology and chemistry · 2025-12-11
pmid:41435767
Sex- and Depression-specific Effects of Non-pathogenic CAG Repeats in
Linjun,Ao, Raymond,Noordam, N,Ahmad Aziz, Yuri,Milaneschi, Diana,van Heemst, Frits R,Rosendaal, Brenda W J H,Penninx, Ko Willems,van Dijk, Tamar,Sofer, Heming,Wang, Tariq,Faquih
medRxiv : the preprint server for health sciences · 2025-11-27
pmid:41358280
The genetic landscape of spinocerebellar ataxias in Taiwan: Insights from 876 genetically confirmed cases.
Shih-Chun,Lan, Cheng-Tsung,Hsiao, Kang-Yang,Jih, Yi-Chu,Liao, Yi-Chung,Lee
Parkinsonism & related disorders · 2025-10-12
pmid:41082794
Large-scale genetic characterization of Parkinson's disease in the African and African admixed populations.
Fulya,Akçimen, Kimberly,Paquette, Peter,Wild Crea, Kathryn,Step, Emily,Waldo, Mathew J,Koretsky, Paula,Saffie-Awad, Charles,Achoru, Funmilola,Taiwo, Simon,Ozomma, Gerald,Onwuegbuzie, Marzieh,Khani, Spencer,Grant, Lukman,Owolabi, Chiamaka,Okereke, Olajumoke,Oshinaike, Emmanuel,Iwuozo, Suleyman,Can Akerman, Paul Suhwan,Lee, Shyngle,Oyakhire, Nosakhare,Osemwegie, Kensuke,Daida, Sani,Abubakar, Adedunni,Olusanya, Mariam,Isayan, Christiane,Alvarez, Rami,Traurig, Adebimpe,Ogunmodede, Sarah,Samuel, Mary B,Makarious, Fadimatu,Sa'ad, Rashidat,Olanigan, Kristin,Levine, Ewere Marie,Ogbimi, Dan,Vitale, Francis,Odiase, Francis,Ojini, Olanike,Odeniyi, Zih-Hua,Fang, Nkechi,Obianozie, Deborah A,Hall, Ernest,Nwazor, Tao,Xie, Francesca,Nwaokorie, Mahesh,Padmanaban, Paul,Nwani, Ejaz A,Shamim, Alero,Nnama, David,Standaert, Morenikeji,Komolafe, Marissa,Dean, Godwin,Osaigbovo, Elizabeth,Disbrow, Ismaila,Ishola, Ashley,Rawls, Frank,Imarhiagbe, Shivika,Chandra, Cyril,Erameh, Vanessa,Hinson, Naomi,Louie, Ahmed,Idowu, J,Solle, Scott A,Norris, Abdullahi,Ibrahim, Camilla,Kilbane, Gauthaman,Sukumar, Lisa M,Shulman, Daniel,Ezuduemoih, Julia,Staisch, Sarah,Breaux, Clifton,Dalgard, Erin R,Foster, Abiodun,Bello, Andrew,Ameri, Raquel,Real, Erica,Ikwenu, Huw R,Morris, Roosevelt,Anyanwu, Erin,Furr Stimming, Kimberley,Billingsley, Wemimo,Alaofin, Pilar,Alvarez Jerez, Osigwe,Agabi, Dena G,Hernandez, Rufus,Akinyemi, Sampath,Arepalli, Laksh,Malik, Raymond,Owolabi, Yakub,Nyandaiti, Hampton L,Leonard, Kolawole,Wahab, Oladunni,Abiodun, Carlos F,Hernandez, Fatima,Abdulai, Hirotaka,Iwaki, Soraya,Bardien, Christine,Klein, John,Hardy, Henry,Houlden, Kamalini Ghosh,Galvelis, Mike A,Nalls, Nabila,Dahodwala, Whitley,Aamodt, Emily,Hill, Alberto,Espay, Stewart,Factor, Chantale,Branson, Cornelis,Blauwendraat, Andrew B,Singleton, Oluwadamilola,Ojo, Lana M,Chahine, Njideka,Okubadejo, Sara,Bandres-Ciga
Brain : a journal of neurology · 2025-10-08
pmid:41058593
Repeat Variants, Biomarkers, and Molecular Signatures in Parkinson's Disease:
Jose Miguel,Laffita-Mesa, Martin,Paucar, Per,Svenningsson
International journal of molecular sciences · 2025-09-20
pmid:41009775
Spinocerebellar ataxias masquerading as movement disorders: clinical and genetic characterization.
Shanshan,Wei, Zhe,Zhao, Nan,Li, Xuan,Guo, Jiannan,Chen, Jing,Hu
Frontiers in neurology · 2025-09-10
pmid:41001200
Ocular Motor and Vestibular Profile in Spinocerebellar Ataxia Type 27B: Toward a Practical Bedside Diagnostic Framework.
Leonardo Eleuterio,Ariello, Daniel R,Gold, Weiyi,Mu, Michael C,Schubert, Claire,Allen, Ashley,Paul, David P W,Rastall
Cerebellum (London, England) · 2025-09-04
pmid:40906330
The Case of Spinocerebellar Ataxias in Amazonas (Northern Brazil): An Analysis of Disease Frequency from a Geographic, Historical, and Genetic-Evolutionary Perspective.
Diana Vieira,Brito, Marcus Vinicius,Della Coletta, Giselle Benevides Monteiro,Ferreira, Sabrina Rodrigues,da Silva, Patricia Batista de,Azevedo, Cleiton,Fantin
Cerebellum (London, England) · 2025-09-03
pmid:40900235
Long-read sequencing identifies ATXN3 repeat expansions, and transcriptomics reveals disease progression biomarkers and druggable targets for spinocerebellar ataxia type 3.
Chang,Liu, Xin,Wang, Chao,Xu, Xiaoxiang,Liu, Liyan,Ke, Ying,Li, Hang,Zhang, Jianqiang,Tan, Senwei,Tan, Zitong,Zhang, Liang,Cheng, Yaqiong,Ren, Lei,Shi
BMC neurology · 2025-09-01
pmid:40890629