Genetic testing was unremarkable for additional microdeletions or microduplications and was negative for the fragile X premutation
Frequency and stability of the myotonic dystrophy type 1 premutation
. Neurology 2001;56: 328-35.
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).
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.
(PM) carriers have expansions of 55 to 200 repeats, which are not associated with ID.
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.