Spinocerebellar ataxia type 31 (SCA31) is a very rare subtype of autosomal dominant cerebellar ataxia type III (ADCA type III) characterized by the late-onset of cerebral ataxia, dysarthria and horizontal gaze nystagmus, and that is occasionally accompanied by pyramidal signs, tremor, decreased vibration sense and hearing difficulties¹.

Prevalence

Has been found in Japanese populations²and then once respectively in a Korean and a Chinese family³.

Age of Onset

Typical: 56-62³; Range: 8-83⁴.

HPO Terms

–

Association

Mendelian

Locus

hg19 chr16:66524299-66524369

hg38 chr16:66490396-66490466

t2t chr16:72284666-72284761

Details

This locus is a novel STR-containing insertion, not present in reference genome; the pathogenic threshold (110-760) is based on the pure repeat of the pathogenic motif within the insertion⁵.

Mechanism

GoF

RNA toxicity and gain of function leading to neurodegeneration⁶. Role in heterochromatin or chromosomal structure theorized².

Detection

RP-PCR has accurately detected this insertion [@pmid:22992774], while long-read sequencing has resolved size and motif architecture [@pmid:36289212].

Year

2009⁵

Location in Gene

Intron 4/4

Gene Strand

Alleles

Ref. Motif

AATAA

Ranges

Benign (ref.)

–

Benign (gene)

–

Pathogenic (ref.)

TGGAA, TAGAA

Pathogenic (gene)

AATGG, AATAG

Unknown (ref.)

AAAAA, AAAAC, AAATG, AGAAA, ATAAG, TAAAC, TAACA, TACAA, TCAAA, TGCAA

Unknown (gene)

AAAAA, AAAAC, AAATG, AAAAG, AAGAT, AAACT, AACAT, AATAC, AAATC, AATGC

Interruption (ref.)

–

Interruption (gene)

–

gnomAD

References

Direct supporting references for info on this page.

Ontology Lookup Service (OLS)

mondo:0007296

2omim:117210

Spinocerebellar ataxia type 31: A clinical and radiological literature review.

Jacob,Saucier, Mohammad,Al-Qadi, Mouna Ben,Amor, Kinya,Ishikawa, Ludivine,Chamard-Witkowski

Journal of the neurological sciences · 2022-12-16

pmid:36563608

Autosomal dominant cerebellar ataxia type III: a review of the phenotypic and genotypic characteristics.

Shinsuke,Fujioka, Christina,Sundal, Zbigniew K,Wszolek

Orphanet journal of rare diseases · 2013-01-18

pmid:23331413

Spinocerebellar ataxia type 31 is associated with "inserted" penta-nucleotide repeats containing (TGGAA)n.

Nozomu,Sato, Takeshi,Amino, Kazuhiro,Kobayashi, Shuichi,Asakawa, Taro,Ishiguro, Taiji,Tsunemi, Makoto,Takahashi, Tohru,Matsuura, Kevin M,Flanigan, Sawa,Iwasaki, Fumitoshi,Ishino, Yuko,Saito, Shigeo,Murayama, Mari,Yoshida, Yoshio,Hashizume, Yuji,Takahashi, Shoji,Tsuji, Nobuyoshi,Shimizu, Tatsushi,Toda, Kinya,Ishikawa, Hidehiro,Mizusawa

American journal of human genetics · 2009-10-29

pmid:19878914

Phenotype and management of neurologic intronic repeat disorders (NIRDs).

J,Finsterer

Revue neurologique · 2022-11-10

pmid:36371266

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)

Phototriggered Morphological and Compositional Change of UGGAA Repeat RNA Foci by Photoswitchable RNA-Binding Ligand.

Yusuke,Fujiwara, Tomonori,Shibata, Chikara,Dohno

Angewandte Chemie (International ed. in English) · 2026-03-17

pmid:41841436

The role of disease-associated short tandem repeats in amyotrophic lateral sclerosis.

Joke J F A,van Vugt, Ramona A J,Zwamborn, Egor,Dolzhenko, Michael A,Eberle, Ben,Weisburd, Erwin,Bekema, Maarten,Kooyman, Bi-Nan,Wang, Erik-Jan,Kamsteeg, Monique,Losekoot, Frank,Baas, Camilla,Novy, Helle,Høyer, Ruben P A,van Eijk, Michael A,van Es, Wouter,van Rheenen, Ammar,Al-Chalabi, Leonard H,van den Berg, Jan H,Veldink

Brain communications · 2025-12-09

pmid:41426430

Non-coding repeat analyses in patients with Parkinson's disease.

Makito,Hirano, Makoto,Samukawa, Satoko,Miyatake, Yuko,Yamagishi, Chiharu,Isono, Rino,Yoshikawa, Kazumasa,Saigoh, Atsushi,Terayama, Yuji,Higashimoto, Eriko,Koshimizu, Takeshi,Mizuguchi, Kanako,Fujii, Yoshiyuki,Mitsui, Naomichi,Matsumoto, Yoshitaka,Nagai

Frontiers in neurology · 2025-07-22

pmid:40765612

Diagnostic yield and limitations of whole-genome sequencing for hereditary cerebellar ataxia.

Wai Yan,Yau, Roisin,Sullivan, Emer,O'Connor, David,Pellerin, Michael H,Parkinson, Paola,Giunti, Marie-Josée,Dicaire, Matt C,Danzi, Stephan,Züchner, Bernard,Brais, Nicholas W,Wood, Henry,Houlden, Jana,Vandrovcova

Brain communications · 2025-05-17

pmid:40488180

Tremor-associated short tandem repeat intermediate and pathogenic expansions in familial essential tremor.

Xun,Zhou, Runcheng,He, Sheng,Zeng, Mingqiang,Li, Hongxu,Pan, Yuwen,Zhao, Zhenhua,Liu, Qian,Xu, Jifeng,Guo, Xinxiang,Yan, Jinchen,Li, Beisha,Tang, Qiying,Sun

Brain communications · 2024-06-29

pmid:38961870

Incidence of different pressure patterns of spinal cerebellar ataxia and analysis of imaging and genetic diagnosis.

Yufen,Peng, Qi,Tu, Yao,Han, Liang,Gao, Chenyi,Wan

Open life sciences · 2023-12-12

pmid:38152578

Prevalence of repeat expansions causing autosomal dominant spinocerebellar ataxias in Hokkaido, the northernmost island of Japan.

Keiichi,Mizushima, Yuka,Shibata, Shinichi,Shirai, Masaaki,Matsushima, Satoko,Miyatake, Ikuko,Iwata, Hiroaki,Yaguchi, Naomichi,Matsumoto, Ichiro,Yabe

Journal of human genetics · 2023-10-17

pmid:37848721

Synthesis and cloning of long repeat sequences using single-stranded circular DNA.

Afsana,Bhuiyan, Shuichi,Asakawa

Frontiers in bioengineering and biotechnology · 2023-03-09

pmid:36970617

ATTCT and ATTCC repeat expansions in the ATXN10 gene affect disease penetrance of spinocerebellar ataxia type 10.

C Alejandra,Morato Torres, Faria,Zafar, Yu-Chih,Tsai, Jocelyn Palafox,Vazquez, Michael D,Gallagher, Ian,McLaughlin, Karl,Hong, Jill,Lai, Joyce,Lee, Amanda,Chirino-Perez, Angel Omar,Romero-Molina, Francisco,Torres, Juan,Fernandez-Ruiz, Tetsuo,Ashizawa, Janet,Ziegle, Francisco Javier,Jiménez Gil, Birgitt,Schüle

HGG advances · 2022-08-15

pmid:36092952

Locus SCA31 BEAN1

Disease

Locus

Alleles

gnomAD

References

Additional Literature