Nonsense mutation

In <a href="/facts/Genetics/bu8wne0A">genetics</a>, a nonsense mutation is a <a href="/facts/Point_mutation/q30PEGFd">point mutation</a> in a <a href="/facts/DNA_sequence/hsPsNCQW">sequence</a> of <a href="/facts/DNA/nB89Iauz">DNA</a> that results in a nonsense codon, or a premature <a href="/facts/Stop_codon/1yuAkq9X">stop codon</a> in the <a href="/facts/Transcription_(genetics)/bDgp9HDN">transcribed</a> <a href="/facts/MRNA/oUL6qxQn">mRNA</a>, and leads to a truncated, incomplete, and possibly nonfunctional <a href="/facts/Protein/Jxmagu3E">protein</a> product. Nonsense mutations are not always harmful; the functional effect of a nonsense mutation depends on many aspects, such as the location of the <a href="/facts/Stop_codon/1yuAkq9X">stop codon</a> within the coding <a href="/facts/DNA/nB89Iauz">DNA</a>. For example, the effect of a nonsense mutation depends on the proximity of the nonsense mutation to the original stop codon, and the degree to which functional subdomains of the protein are affected. As nonsense mutations leads to premature termination of <a href="/facts/Polypeptide_chain/C4ltc7UG">polypeptide chains</a>; they are also called chain termination mutations.
<a href="/facts/Missense_mutation/uKQ9dC22">Missense mutations</a> differ from nonsense mutations since they are <a href="/facts/Point_mutation/q30PEGFd">point mutations</a> that exhibit a single <a href="/facts/Nucleotide/pQKEwlJI">nucleotide</a> change to cause substitution of a different <a href="/facts/Amino_acid/WDxYwBny">amino acid</a>. A nonsense mutation also differs from a <a href="/facts/Stop_codon/1yuAkq9X">nonstop mutation</a>, which is a point mutation that removes a stop codon. About 10% of patients facing genetic diseases have involvement with nonsense mutations. Some of the diseases that these mutations can cause are <a href="/facts/Duchenne_muscular_dystrophy/VnHhefIk">Duchenne muscular dystrophy</a> (DMD), <a href="/facts/Cystic_fibrosis/tlNK5BAH">cystic fibrosis</a> (CF), <a href="/facts/Spinal_muscular_atrophy/rBzq7qzU">spinal muscular atrophy</a> (SMA), <a href="/facts/Cancer/PVW6n1D0">cancers</a>, <a href="/facts/Metabolic_diseases/mXnwRURT">metabolic diseases</a>, and <a href="/facts/Neurological_disorder/eQKKs7jX">neurologic disorders.</a> The rate of nonsense mutations is variable from gene-to-gene and tissue-to-tissue, but gene silencing occurs in every patient with a nonsense mutation.

Nonsense mutation open-in-new

Nonsense mutation