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Ataxin 2
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols ATXN2 ; ASL13; ATX2; SCA2; TNRC13
External IDs OMIM601517 MGI1277223 HomoloGene2234 ChEMBL: 1795085 GeneCards: ATXN2 Gene
RNA expression pattern
PBB GE ATXN2 202622 s at tn.png
More reference expression data
Species Human Mouse
Entrez 6311 20239
Ensembl ENSG00000204842 ENSMUSG00000042605
UniProt Q99700 O70305
RefSeq (mRNA) NM_001310121 NM_009125
RefSeq (protein) NP_001297050 NP_033151
Location (UCSC) Chr 12:
111.45 – 111.6 Mb
Chr 5:
121.71 – 121.82 Mb
PubMed search [1] [2]

Ataxin-2 is a protein that in humans is encoded by the ATXN2 gene.[1][2]

Mutations in ATXN2 cause spinocerebellar ataxia type 2 (SCA2). The autosomal dominant cerebellar ataxias (ADCA) are a heterogeneous group of neurodegenerative disorders characterized by progressive degeneration of the cerebellum, brain stem and spinal cord. Clinically, ADCA has been divided into three groups: ADCA types I-III. ADCAI is genetically heterogeneous, with five genetic loci, designated spinocerebellar ataxia (SCA) 1, 2, 3, 4 and 6, being assigned to five different chromosomes. ADCAII, which always presents with retinal degeneration (SCA7), and ADCAIII often referred to as the `pure' cerebellar syndrome (SCA5), are most likely homogeneous disorders. Several SCA genes have been cloned and shown to contain CAG repeats in their coding regions. SCA2 is caused by the expansion of a CAG repeat in the coding region of the ATXN2 gene producing an elongated polyglutamine tract in the corresponding protein. The expanded repeats are variable in size and unstable, usually increasing in size when transmitted to successive generations. The function of the ataxins is not known. This locus has been mapped to chromosome 12, and it has been determined that the disease allele usually contains 34-52 CAG repeats, but can contain as few as 32 or more than 100. Normal alleles usually have 22 or 23 repeats, but can contain up to 31 repeats. A potential transcript variant, missing an internal coding exon, has been described; however, its full-length nature is not certain.[3]

In 2010, work from Aaron Gitler and Nancy Bonini at the University of Pennsylvania discovered that intermediate-size CAG repeat expansions are significantly associated with risk for developing amyotrophic lateral sclerosis (Lou Gehrig's disease).[4]


  1. ^ Gispert S, Twells R, Orozco G, Brice A, Weber J, Heredero L, Scheufler K, Riley B, Allotey R, Nothers C; et al. (Sep 1993). "Chromosomal assignment of the second locus for autosomal dominant cerebellar ataxia (SCA2) to chromosome 12q23-24.1". Nat Genet 4 (3): 295–9. doi:10.1038/ng0793-295. PMID 8358438. 
  2. ^ Margolis RL, Abraham MR, Gatchell SB, Li SH, Kidwai AS, Breschel TS, Stine OC, Callahan C, McInnis MG, Ross CA (Jul 1997). "cDNAs with long CAG trinucleotide repeats from human brain". Hum Genet 100 (1): 114–22. doi:10.1007/s004390050476. PMID 9225980. 
  3. ^ "Entrez Gene: ATXN2 ataxin 2". 
  4. ^ Elden AC, Kim HJ, Hart MP, Chen-Plotkin AS, Johnson BS, Fang X, Armakola M, Geser F, Greene R, Lu MM; et al. (Aug 2010). "Ataxin-2 intermediate-length polyglutamine expansions are associated with increased risk for ALS". Nature 466 (7310): 1069–1075. doi:10.1038/nature09320. PMC 2965417. PMID 20740007. 

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