FMR-1 gene | definition of FMR-1 gene by Medical dictionary
A gene found on the X chromosome. Its exact purpose is unknown, but it is suspected that the gene plays a role in brain development.
References in periodicals archive
Affected individuals have >200 CGG repeats and are classified as having a full mutation (FM) which is associated with hypermethylation of an upstream gene promoter region (CpG island) and silencing of FMR-1 gene
transcription which results in the absence of the gene product, fragile X mental retardation protein (FMRP).
Absence of expression of the FMR-1 gene
in fragile X syndrome.
Normal variation in size of the FMR-1 gene
is not associated with variation in intellectual performance.
The severity of fragile X syndrome in an affected individual is usually related to the size of the DNA mutation within the FMR-1 gene
. Some intellectually normal people have a fragile X "premutation," or small mutation.
In these, the affected fmr-1 gene
had 57, 168, 182, 207, 266, or 285 repeats.