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A genetic variant that changes the way codons are read during the process of creating an amino acid sequence.

Use in clinical context

Frameshift variants can have severe implications on the production of the protein that the gene provides instructions for. These variants change the amino acids in the protein by affecting the way the codons of the gene are read during translation.

For example, the codons in the DNA sequence TTT ATG GTC TGC are translated to the amino acids Phe Met Val Trp.

When a single T base is deleted from the beginning of the DNA sequence, it changes to TTA TGG TCT GC. The resulting codons are then translated to Leu Trp Ser.

When amino acids are changed in this way, a different protein will be produced as a result. Frameshift variants can also introduce an early stop codon, which results in a much shorter protein than normal.

Frameshift variants can result in a range of different conditions, including cancer, cystic fibrosis and hypertrophic cardiomyopathy.

Last updated on 4th December, 2020