Repeat Disorders
STR: FXTAS
HGVS nomenclature - NM_002024.5:c.-129_-127CGG[X]
RNA-mediated toxicity may result in the FXTAS phenotype, whereas loss of function through methylation silencing of FMR1 is associated with the FXS phenotype.
Intermediate (grey zone, inconclusive, borderline): ~45 to ~54 repeats
Premutation - risk of FXTAS: ~55 to ~200 repeats
Full mutation - fragile X syndrome (FXS): >200 repeats
Sources: Expert listCreated: 26 Aug 2021, 9:55 a.m.
Mode of inheritance
X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Phenotypes
Fragile X tremor/ataxia syndrome MIM#300623
Publications
Clinically RelevantInterruptions in the repeated sequence are reported as part of standard diagnostic practise
Tag adult-onset tag was added to STR: FXTAS.
Str: fxtas has been classified as Green List (High Evidence).
Str: fxtas has been classified as Green List (High Evidence).
STR: FXTAS was added STR: FXTAS was added to Repeat Disorders. Sources: Expert list Mode of inheritance for STR: FXTAS was set to X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males) Publications for STR: FXTAS were set to 23765048; 25227148; 11445641 Phenotypes for STR: FXTAS were set to Fragile X tremor/ataxia syndrome MIM#300623 Review for STR: FXTAS was set to GREEN STR: FXTAS was marked as clinically relevant