Table 4.

Molecular codes for refSNPs in gene features

Functional classDefinition/ExampledbSNP codeSequence Ontology Code
(term definition)
cds-synonSynonymous change. Example: rs248, GAG->GAA, both produce amino acid: Glu3 SO​:0001819
intronExample: rs2496 SO​:0001627
cds-referenceContig reference8
synonymy unknownCoding: synonymy unknown. Not used since 20039
nearGene-3Within 3' 0.5kb to a gene. Example:rs3916027 is at NT_030737.9 pos7669796, within 500
bp of UTR starts 7669698 for NM_000237.2
13 SO​:0001634
nearGene-5Within 5' 2kb to a gene. Example: rs7641128 is at NT_030737.9 pos7641128, with 2K bp of UTR starts 7641510 for NM_000237.215 SO​:0001636
intergenicVariant between two genes, outside of 2Kb upstream and 500bp downstream of a gene20 SO​:0001628
ncRNAVariant on non-coding RNA(NCBI Refseq prefix NR,XR)30 SO​:0001619
STOP-GAINChanges to STOP codon. Example: rs328, TCA->TGA, Ser to terminator41 SO​:0001587
missenseAlters codon to make an altered amino acid in protein product. Example: rs300, ACT->GCT, Thr->Ala42 SO​:0001583
STOP-LOSSChanges STOP codon to other non stop codon43 SO​:0001578
frameshiftIndel snp causing frameshift44 SO​:0001589
cds-indelIndel snp with length of multiple of 3bp, not causing frameshift45 SO​:0001650
UTR-33 prime untranslated region. Example: rs328953 SO​:0001624
UTR-55 prime untranslated region. Example: rs180059055 SO​:0001623
splice-33 prime acceptor dinucleotide. The last two bases in the 3 prime end of an intron. Most intron ends with AG. Example: rs193227 is in acceptor site.73 SO​:0001574
splice-55 prime donor dinucleotide. 1st two bases in the 5 prime end of the intron. Most intron starts is GU. Example: rs8424 is in donor site.75 SO​:0001575

Most gene features are defined by the location of the variation with respect to transcript exon boundaries. Variations in coding regions, however, have a functional class assigned to each allele for the variation because these classes depend on allele sequence.

From: The Database of Short Genetic Variation (dbSNP)

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