XIST |
- 3
Haplo
Score - 0
Triplo
Score
Gene Facts External Data Attribution
- HGNC Symbol
- XIST (HGNC:12810) HGNC Entrez Ensembl OMIM UCSC GeneReviews LOVD LSDB ClinVar
- HGNC Name
- X inactive specific transcript
- Gene type
- non-coding RNA
- Locus type
- RNA, long non-coding
- Previous symbols
- DXS399E
- Alias symbols
- NCRNA00001, DXS1089, swd66, LINC00001
- %HI
- 0(Read more about the DECIPHER Haploinsufficiency Index)
- pLI
- 0(Read more about gnomAD pLI score)
- Cytoband
- Xq13.2
- Genomic Coordinates
-
GRCh37/hg19: chrX:73040486-73072588 NCBI Ensembl UCSC GRCh38/hg38: chrX:73820651-73852753 NCBI Ensembl UCSC
Dosage Sensitivity Summary (Gene)
Haploinsufficiency (HI) Score Details
- X inactivation, familial skewed, 1 Monarch
-
PUBMED:
8265665
Migeon et al (1993) describe 8 females with small ring X chromosomes and a severe phenotype including intellectual disability. Seven had either absent XIST confirmed by FISH or a lack of RNA by RT-PCR. The remaining patient had two rings, one large ring with XIST present and one small ring with XIST absent by FISH. This lack of functional XIST prevented the ring chromosome from inactivating and led to a more severe phenotype than typically is seen in girls with Turner syndrome.
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PUBMED:
11896455
Tomkins et al., 2002 - Peripheral blood chromosome analysis in a 3.5 year old female with short stature, DD, and facial dysmorphism revealed 28% of cells with 45,X karyotype, and 72% with 46,X,r(X). XIST was present on the ring, but no XIST expression was detected. The ring was paternally derived and was not inactivated. The ring carried C(-43)A variant in the XIST promoter. The patient’s maternal grandmother also carried this variant on one of her X chromosomes, and it was more strongly associated with the active X, although she only showed 60:40 skewing of XCI. Since skewing increases with age, this result is not significantly different from the general population.
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PUBMED:
28947658
de Hoon et al., 2017 - 26 year old women with no ID or facial dysmorphism presented with ovarian dysgenesis aka premature ovarian insufficiency (POI). Normal karyotype, but SNP array analysis identified a 1.28 Mb deletion of the X-inactivation center (XIC) including XIST and several other genes. Several regions of LOH were also observed, consistent with history of parental consanguinity. X-inactivation was skewed 93:7 towards inactivation of the normal X.
The loss-of-function and triplosensitivity ratings for genes on the X chromosome are made in the context of a male genome to account for the effects of hemizygous duplications or nullizygous deletions. In contrast, disruption of some genes on the X chromosome causes male lethality and the ratings of dosage sensitivity instead take into account the phenotype in female individuals. Factors that may affect the severity of phenotypes associated with X-linked disorders include the presence of variable copies of the X chromosome (i.e. 47,XXY or 45,X) and skewed X-inactivation in females.
Triplosensitivity (TS) Score Details
The loss-of-function and triplosensitivity ratings for genes on the X chromosome are made in the context of a male genome to account for the effects of hemizygous duplications or nullizygous deletions. In contrast, disruption of some genes on the X chromosome causes male lethality and the ratings of dosage sensitivity instead take into account the phenotype in female individuals. Factors that may affect the severity of phenotypes associated with X-linked disorders include the presence of variable copies of the X chromosome (i.e. 47,XXY or 45,X) and skewed X-inactivation in females.