X-147936614-G-T

Variant names:

• chrX-147936614-G-T
• rs886041089
• NM_002024.6:c.990+1G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_002024.6(FMR1):​c.990+1G>T variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: FMR1 NM_002024.6 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.08
• Publications: 0 publications found

Genes affected

FMR1 (HGNC:3775): (fragile X messenger ribonucleoprotein 1) The protein encoded by this gene binds RNA and is associated with polysomes. The encoded protein may be involved in mRNA trafficking from the nucleus to the cytoplasm. A trinucleotide repeat (CGG) in the 5' UTR is normally found at 6-53 copies, but an expansion to 55-230 repeats is the cause of fragile X syndrome. Expansion of the trinucleotide repeat may also cause one form of premature ovarian failure (POF1). Multiple alternatively spliced transcript variants that encode different protein isoforms and which are located in different cellular locations have been described for this gene. [provided by RefSeq, May 2010]

FMR1 Gene-Disease associations (from GenCC):

• fragile X syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• fragile X-associated tremor/ataxia syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Ambry Genetics
• premature ovarian failure 1

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• symptomatic form of fragile X syndrome in female carrier

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.057925224 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.1, offset of -45, new splice context is: aggGTgagg. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-147936614-G-T is Pathogenic according to our data. Variant chrX-147936614-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 2504902.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FMR1	NM_002024.6	c.990+1G>T		splice_donor_variant, intron_variant	Intron 10 of 16	ENST00000370475.9	NP_002015.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FMR1	ENST00000370475.9	c.990+1G>T		splice_donor_variant, intron_variant	Intron 10 of 16	1	NM_002024.6	ENSP00000359506.5

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 21

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Dec 06, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.65	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	33
DANN	Uncertain	1.0
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		9.1
GERP RS		5.5
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.42		Position offset: -46
DS_DL_spliceai		1.0		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs886041089; hg19: chrX-147018133; COSMIC: COSV99503160; COSMIC: COSV99503160;