Repeat Disorders

STR: FXTAS

Green List (high evidence)

Chromosome: X
GRCh37 Position: 146993569-146993628
GRCh38 Position: 147912051-147912110
Repeated Sequence: CGG
Normal Number of Repeats: < or = 44
Pathogenic Number of Repeats: = or > 55

FMR1 (fragile X mental retardation 1)
EnsemblGeneIds (GRCh38): ENSG00000102081
EnsemblGeneIds (GRCh37): ENSG00000102081
OMIM: 309550, Gene2Phenotype
FMR1 is in 11 panels

1 review

Bryony Thompson (Royal Melbourne Hospital)

Green List (high evidence)

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 list
Created: 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 Relevant

Interruptions in the repeated sequence are reported as part of standard diagnostic practise

Details

Name
FXTAS
Chromosome
X
GRCh37 Coordinates
146993569-146993628
GRCh38 Coordinates
147912051-147912110
Repeated Sequence
CGG
Normal Number of Repeats: < or =
44
Pathogenic Number of Repeats: = or >
55
Mode of Inheritance
X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Sources
  • Expert Review Green
  • Expert list
Phenotypes
  • Fragile X tremor/ataxia syndrome MIM#300623
Tags
adult-onset
OMIM
309550
Clinvar variants
Variants in FMR1
Penetrance
None
Publications

History Filter Activity

1 Sep 2021, Gel status: 3

Added Tag

Zornitza Stark (Victorian Clinical Genetics Services; Australian Genomics)

Tag adult-onset tag was added to STR: FXTAS.

26 Aug 2021, Gel status: 3

Entity classified by Genomics England curator

Bryony Thompson (Royal Melbourne Hospital)

Str: fxtas has been classified as Green List (High Evidence).

26 Aug 2021, Gel status: 3

Entity classified by Genomics England curator

Bryony Thompson (Royal Melbourne Hospital)

Str: fxtas has been classified as Green List (High Evidence).

26 Aug 2021, Gel status: 1

Created, Added New Source, Set mode of inheritance, Set publications, Set Phenotypes

Bryony Thompson (Royal Melbourne Hospital)

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