title: Fragile X-associated tremor/ataxia syndrome (FXTAS) in grey zone carriers.
abstract: The grey zone (GZ; 45-54 CGG repeats in the FMR1 gene) is considered a normal allele; however, several studies have found a high frequency of GZ in movement disordered populations. Here, we describe neurological features of fragile X-associated tremor/ataxia syndrome (FXTAS) in two carriers of GZ alleles, although FXTAS has been defined as occurring only in premutation carriers (55-200 CGG repeats). Both patients had family members who had premutation and were diagnosed with FXTAS. The presence of relatively high GZ alleles with elevated fragile X mental retardation 1 mRNA (FMR1-mRNA) combined with a family history of FXTAS that may represent a facilitating genetic background for FXTAS are the factors that led to the presence of FXTAS in these individuals with a GZ allele. Further research into clinical involvement of GZ alleles is recommended and the definition of FXTAS may require revision.
authors.affiliation: Department of Neurology, Dalian Municipal Friendship Hospital, Dalian, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: T I
authors.initials: TI
authors.lastname: Winarni
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: F
authors.initials: F
authors.lastname: Tassone
authors.forename: R J
authors.initials: RJ
authors.lastname: Hagerman
mesh_terms: D000369:Aged, 80 and over; D000483:Alleles; D001259:Ataxia / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005600:Fragile X Syndrome / Q000235:genetics* / Q000503:physiopathology; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D012333:RNA, Messenger / Q000235:genetics*; D014202:Tremor / Q000235:genetics* / Q000503:physiopathology; D018911:Trinucleotide Repeats
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D012333:RNA, Messenger; C497683:FMR1 protein, human