premutation


Also found in: Encyclopedia.

premutation

(pre?mu-ta'shun)
A sequence of multiply repeated nucleotides that may produce a disease in one's offspring but may not produce clinically apparent disease in the carrier. A common premutation occurs in the Fragile X syndrome, in which ancestors of affected children may have 50 — 200 copies of the trinucleotide sequence CGG. These individuals do not have the full phenotypic expression of the Fragile X syndrome but as adults may suffer Parkinson-like movement disorders such as ataxia and tremors.
Synonym: intermediate allele
Medical Dictionary, © 2009 Farlex and Partners

Premutation

A change in a gene that precedes a mutation; this change does not alter the function of the gene.
Mentioned in: Fragile X Syndrome
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Genetic testing was unremarkable for additional microdeletions or microduplications and was negative for the fragile X premutation.
The carriers of the premutation alleles can exhibit 3 clinical forms, i.e.
Expanded CGG triplets in the premutation range (55-200 CGG) in the FMRI gene are responsible for this syndrome (2,3,4,5).
Multiresponse premutation is a nonparametric procedure for testing differences between two or more groups; the advantage of this method is that it does not involve assumptions (such as multivariate normality and homogeneity of variances) that are seldom met with ecological data on community (McCune and Grace, 2002).
However, in Case 4, though the expansion was of a sporadic event and the parents were not premutation carriers, the proband is affected and a source of transmitting the affected gene to his offspring.
Rabaia et al., "An antisense transcript spanning the CGG repeat region of FMR1 is upregulated in premutation carriers but silenced in full mutation individuals," Human Molecular Genetics, vol.
For example, not all pan-ethnic panels include analysis for premutation carriers, making it important to inquire about a history of unexplained mental retardation and autism in males, since this may stem from Fragile X syndrome.
For example, it is very important to accurately determine the size of fragile X premutation expansions to correctly predict the risk of allelic expansion, premature ovarian failure, and fragile X-associated tremor/ataxia syndrome.
Participants consisted of students with singing voices in premutation, during mutation, and postmutation vocal stages.