FRAXA fragile site, folic acid type, rare, fra(X)(q27.3) A [Homo sapiens (human)] - Gene

Summary

Official Symbol: FRAXAprovided by HGNC
Official Full Name: fragile site, folic acid type, rare, fra(X)(q27.3) Aprovided by HGNC
Primary source: HGNC:HGNC:3945
See related: AllianceGenome:HGNC:3945
Gene type: biological region
Feature type(s): misc_feature: repeat_instability_region
repeat_region
RefSeq status: REVIEWED
Organism: Homo sapiens
Lineage: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
Also known as: FMR1
Summary: This biological region is found near the 5' regulatory region of the Fragile X messenger ribonucleoprotein 1 (FMR1) gene on the q arm of chromosome X, and contains a CGG trinucleotide repeat with AGG repeat interruptions. This region is highly polymorphic, and alleles with varying numbers of repeats have been observed. Alleles with repeat sizes of 5-44 tend to show mitotic and meiotic stability, while those with about 45-54 repeats are at a higher risk for instability, but show no phenotype. Individuals with alleles that are expanded to 55-200 repeats are at risk for a number of disorders, including fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated premature ovarian insufficiency (FXPOI), and adult-onset neurodegenerative disorder. These alleles tend to be unstable upon transmission, with a bias for expansion during maternal transmission. Alleles containing more than 200 CGG repeats are considered full mutation alleles, and are associated with fragile X syndrome. These alleles display hypermethylation of the FMR1 promoter region. It has been shown that the presence of AGG interruptions reduce the risk of repeat instability. [provided by RefSeq, Apr 2022]
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Genomic context

Location:: Xq27.3

Annotation release	Status	Assembly	Chr	Location
RS_2023_10	current	GRCh38.p14 (GCF_000001405.40)	X	NC_000023.11 (147911979..147912111)
RS_2023_10	current	T2T-CHM13v2.0 (GCF_009914755.1)	X	NC_060947.1 (146176607..146176769)
105.20220307	previous assembly	GRCh37.p13 (GCF_000001405.25)	X	NC_000023.10 (146993497..146993629)

Chromosome X - NC_000023.11 Genomic Context describing neighboring genes

Genomic regions, transcripts, and products

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Genomic Sequence:

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Bibliography

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GeneRIFs: Gene References Into Functions

What's a GeneRIF?

Quadruplex-forming properties of FRAXA (CGG) repeats interrupted by AGG triplets are reported.
Title: Quadruplex-forming properties of FRAXA (CGG) repeats interrupted by (AGG) triplets.
This finding in French families with Dyslexia showed significant linkage on Xq27.3 enclosing FRAXA
Title: Xq27 FRAXA locus is a strong candidate for dyslexia: evidence from a genome-wide scan in French families.
Two patients carrying FRAXA premutation alleles were identified showing clinical manifestations indistinguishable from idiopathic Parkinson's disease
Title: Intermediate alleles at the FRAXA and FRAXE loci in Parkinson's disease.
Allele and haplotype distribution in the normal controls and fragile X groups were significantly different, suggesting a weak founder effect.
Title: Haplotype analysis at the FRAXA locus in an Indian population.
Observational study of genotype prevalence and gene-disease association. (HuGE Navigator)
Title: Fragile X premutation in women with sporadic premature ovarian failure in Slovenia.
Observational study of genotype prevalence. (HuGE Navigator)
Title: Mutation screening of the MECP2 gene in a large cohort of 613 fragile-X negative patients with mental retardation.
Observational study of genetic testing. (HuGE Navigator)
Title: Validity of analysis of FMRP expression in blood smears as a screening test for Fragile X Syndrome in the Indian population.
Observational study of gene-disease association. (HuGE Navigator)
Title: Haplotype analysis at the FRAXA locus in an Indian population.

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Phenotypes

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Find tests for this gene in the NIH Genetic Testing Registry (GTR)

Review eQTL and phenotype association data in this region using PheGenI

Variation

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See variants in ClinVar

See Variation Viewer (GRCh37.p13)

General gene information

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Other Names

FMR1 repeat instability region
FRAXA repeat instability region
fragile site, folic acid type, rare, fra(X)(q27.3) A repeat instability region

NCBI Reference Sequences (RefSeq)

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RefSeqs maintained independently of Annotated Genomes

These reference sequences exist independently of genome builds. Explain

These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.