chrX-21737698-C-T

Variant names:

• chrX-21737698-C-T
• rs1060499590
• NM_014332.3:c.133-1G>A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_014332.3(SMPX):​c.133-1G>A variant causes a splice acceptor, intron change. 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 Likely pathogenic (no stars).

• Frequency: Genomes: not found (cov: 23)
• Consequence: SMPX NM_014332.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.41
• Publications: 6 publications found

Genes affected

SMPX (HGNC:11122): (small muscle protein X-linked) This gene encodes a small protein that has no known functional domains. Mutations in this gene are a cause of X-linked deafness-4, and the encoded protein may play a role in the maintenance of inner ear cells subjected to mechanical stress. Alternatively spliced transcript variants have been observed for this gene. [provided by RefSeq, Dec 2011]

SMPX Gene-Disease associations (from GenCC):

• nonsyndromic genetic hearing loss

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• hearing loss, X-linked 4

  Inheritance: XL Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)
• myopathy, distal, 7, adult-onset, X-linked

  Inheritance: XL Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
• X-linked nonsyndromic hearing loss

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 11, offset of 1, new splice context is: tcttctccttgctcttcaAGgtg. Cryptic site results in frameshift 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-21737698-C-T is Pathogenic according to our data. Variant chrX-21737698-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 417903.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014332.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPX	NM_014332.3	MANE Select	c.133-1G>A		splice_acceptor intron	N/A	NP_055147.1	Q9UHP9
	SMPX	NR_045617.2		n.320-1G>A		splice_acceptor intron	N/A

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMPX	ENST00000379494.4	TSL:1 MANE Select	c.133-1G>A		splice_acceptor intron	N/A	ENSP00000368808.3	Q9UHP9
	SMPX	ENST00000646008.1		c.133-1G>A		splice_acceptor intron	N/A	ENSP00000493671.1	Q9UHP9
	SMPX	ENST00000867835.1		c.133-1G>A		splice_acceptor intron	N/A	ENSP00000537894.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 23

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Hearing loss, X-linked 4 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	34
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		5.4
GERP RS		5.3
Mutation Taster		=24/76	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.98		Position offset: -2
DS_AL_spliceai		0.99		Position offset: -1

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

Other links and lift over

dbSNP: rs1060499590; hg19: chrX-21755816;