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Fragile X‐associated tremor/ataxia syndrome ( FXTAS ) in grey zone carriers
Author(s) -
Liu Y,
Winarni TI,
Zhang L,
Tassone F,
Hagerman RJ
Publication year - 2013
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/cge.12026
Subject(s) - ataxia , fmr1 , fragile x syndrome , fragile x , allele , genetics , medicine , biology , psychiatry , gene
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.