Premature termination codon caused by Arg-to-TGA mutation in mRNA

A premature termination codon (PTC) Arg-TGA in mRNA occurs when a point mutation converts a codon for arginine (such as CGA) to the stop codon TGA within a gene's coding sequence. This results in the early termination of translation, leading to truncated, usually nonfunctional, and sometimes toxic protein products. The truncated mRNA may also be rapidly degraded by the nonsense-mediated decay pathway. PTCs are significant contributors to severe genetic diseases, including cystic fibrosis, Duchenne muscular dystrophy, and many others. Therapeutically, small molecules and engineered tRNAs are being explored to enable readthrough of PTCs, restoring some full-length protein production.

Other names

Premature stop codon (Arg-to-TGA)Opal nonsense mutation at Arg codonNonsense codon (Arg to TGA)

Promoting translational readthrough of premature stop codons (e.g., by Ataluren or aminoglycosides)