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A type of codon that shows where to stop transcribing a gene. Stop codons are TAG, TGA and TAA.

Use in clinical context

Nonsense variants can arise in a gene and this introduces a premature stop codon into the sequence, stopping translation and resulting in a short mRNA and short protein. Usually this causes incorrect protein function, with resulting phenotypic effects for the individual. Nonsense variants can cause some rare conditions, including cystic fibrosis and beta-thalassaemia.

Last updated on 30th December, 2021