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LOC109029533 cystatin B upstream repeat instability region [ Homo sapiens (human) ]

Gene ID: 109029533, updated on 18-May-2021


Gene symbol
Gene description
cystatin B upstream repeat instability region
Gene type
biological region
Feature type(s)
misc_feature: repeat_instability_region
RefSeq status
Homo sapiens
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
This biological region is found just upstream of the cystatin B (CSTB) gene on the q arm of chromosome 22, and contains a CCCCGCCCCGCG dodecamer repeat. Allelic variation in this region has been observed, but the reference genome contains three copies of the repeat. Expansions of this repeat are known to be a cause of progressive myoclonus epilepsy of the Unverricht-Lundborg type (EPM1), an autosomal recessive disorder. Alleles with 12-17 repeats display reduced stability, while expanded alleles of about 45-75 repeats have been observed, and are disease-causing. Expansion of the repeat results in reduced expression of cystatin B in some cell types. In vitro studies indicate that the dodecamer repeat may adopt secondary structures. [provided by RefSeq, Nov 2016]
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Genomic context

See LOC109029533 in Genome Data Viewer
Annotation release Status Assembly Chr Location
109.20210514 current GRCh38.p13 (GCF_000001405.39) 21 NC_000021.9 (43776443..43776479)
105.20201022 previous assembly GRCh37.p13 (GCF_000001405.25) 21 NC_000021.8 (45196324..45196360)

Chromosome 21 - NC_000021.9Genomic Context describing neighboring genes Neighboring gene PDXK-CSTB intergenic CAGE-defined low expression enhancer Neighboring gene cystatin B Neighboring gene uncharacterized LOC105372825 Neighboring gene transmembrane protein 97 pseudogene 1

Genomic regions, transcripts, and products

General gene information

Other Names

  • CSTB upstream repeat instability region
  • EPM1 repeat instability region
  • progressive myoclonus epilepsy repeat instability region

NCBI Reference Sequences (RefSeq)

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RefSeqs maintained independently of Annotated Genomes

These reference sequences exist independently of genome builds. Explain

These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.


  1. NG_052013.1 

    GenBank, FASTA, Sequence Viewer (Graphics)

RefSeqs of Annotated Genomes: Homo sapiens Updated Annotation Release 109.20210514

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference GRCh38.p13 Primary Assembly


  1. NC_000021.9 Reference GRCh38.p13 Primary Assembly

    GenBank, FASTA, Sequence Viewer (Graphics)
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