null mutation


Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
Related to null mutation: frameshift mutation

null mutation

1. A change in DNA or RNA that does not result in any change in the protein product or content of a cell.
2. A change in a nucleotide that results in the complete failure of protein synthesis by a cell.
See also: mutation

null mutation

A mutation that eliminates the function of the affected gene. In many cases the null mutation is a complete deletion of the gene.
Mentioned in ?
References in periodicals archive ?
We carefully selected heterozygote FH patients on the basis of a null mutation to avoid confounding biases of having residual LDLR activity that may be present in other mutations of the LDLR gene.
Our results supported the previously published findings reporting an association between the GSTM1 null mutation and endometriosis (23,34).
The c.2031-2A>C and the R569W mutation have been published as null mutations, i.e., no residual MPO activity was detected (28-30).
The initial study carried out in 2000 found that FANCA individuals with homozygous null mutations had a higher frequency of somatic anomalies than individuals with FANCC mutations, but a similar frequency to those with FANCG mutations.
(1-4) The autosomal-dominant form is caused by dominant hypomorphic signal transducer and activator of transcription 3 (STAT3) mutations, often involving the DNA-binding and SRC homology 2 protein domains, while the recessive form is caused by null mutations of the dedicator of cytokinesis-8 (DOCK8) and tyrosine kinase-2 (Tyk2) genes.
In the few patients who have been studied, mutations that totally eliminate the ability to produce any functional protein product (i.e, functionally null mutations) have been discovered.
The association between null mutations in the filaggrin gene and contact sensitization to nickel and other chemicals in the general population.
They found 7 African Americans with null mutations in PCSK9.
It is caused by null mutations at WRN locus, which codes for a member of RecQ family of DNA helicases.6-9,11 The disease is associated with excessive synthesis of collagen type I and III which is dependent on elevated messenger RNA(mRNA) levels.6 The locus of Werner Syndrome has been found on the short arm of chromosome 8 in both Japanese and non Japanes.5,7,11 Fibroblasts isolated from WS patients exhibit genomic instability, increased sensitivity to specific DNA damaging agents, slow proliferation, lengthened S-phase, and accelerated replicative senescence.5,7,16
Residual guanosine 3', 5'-bispyrophosphate synthetic activity of relA null mutants can be eliminated by spoT null mutations. J Biol Chem 1991; 266: 5980-90.
Null mutations in lin-14, for example, result in the activation of LIN-29 one stage too early, with the result that certain adult features are precociously expressed in larval stages.
[sup][5] derived a global IV clinical severity score (0–15) by scoring each of five IV clinical signs (diffuse xerosis, hyperlinearity of palms, scales on legs, scalp desquamation, and keratosis pilaris) from 0 to 3 points and genotyping two common FLG null mutations (R501X and 2282del4) for 110 Caucasian patients.