X-153794756-T-C

Position:

• chrX-153794756-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_006280.3(SSR4):​c.67+2T>C variant causes a splice donor change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 26)
• Consequence: SSR4 NM_006280.3 splice_donor
• Scores: Splicing: ADA: 0.9762
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.06

Genes affected

SSR4 (HGNC:11326): (signal sequence receptor subunit 4) This gene encodes the delta subunit of the translocon-associated protein complex which is involved in translocating proteins across the endoplasmic reticulum membrane. The encoded protein is located in the Xq28 region and is arranged in a compact head-to-head manner with the isocitrate dehydrogenase 3 (NAD+) gamma gene and both genes are driven by a CpG-embedded bidirectional promoter. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Mar 2011]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.16475096 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SSR4	NM_006280.3	c.67+2T>C		splice_donor_variant		ENST00000370086.8	NP_006271.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SSR4	ENST00000370086.8	c.67+2T>C		splice_donor_variant		1	NM_006280.3	ENSP00000359103	P1

Frequencies

GnomAD3 genomes Cov.: 26

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 26

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 29, 2021

The c.100+2T>C intronic variant results from a T to C substitution two nucleotides after coding exon 2 of the SSR4 gene. Alterations that disrupt the canonical splice site are expected to result in aberrant splicing. The resulting transcript is predicted to be in-frame and is not expected to trigger nonsense-mediated mRNA decay; however, direct evidence is unavailable. The exact functional effect of the altered amino acid sequence is unknown. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site and will result in the creation or strengthening of a novel splice donor site. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Uncertain	-0.070
CADD	Pathogenic	30
DANN	Benign	0.97
FATHMM_MKL	Benign	0.57	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.98
dbscSNV1_RF	Benign	0.53
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.57		Position offset: 48
DS_DL_spliceai		0.99		Position offset: -2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-153060211;