rs587783769

Positions:

• chrX-150658032-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_000252.3(MTM1):​c.1260+5G>A variant causes a splice donor 5th base, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 24)
• Consequence: MTM1 NM_000252.3 splice_donor_5th_base, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 5.17

Genes affected

MTM1 (HGNC:7448): (myotubularin 1) This gene encodes a dual-specificity phosphatase that acts on both phosphotyrosine and phosphoserine. It is required for muscle cell differentiation and mutations in this gene have been identified as being responsible for X-linked myotubular myopathy. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant X-150658032-G-A is Pathogenic according to our data. Variant chrX-150658032-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 158911.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MTM1	NM_000252.3	c.1260+5G>A		splice_donor_5th_base_variant, intron_variant		ENST00000370396.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MTM1	ENST00000370396.7	c.1260+5G>A		splice_donor_5th_base_variant, intron_variant		1	NM_000252.3	P1

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 24

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Severe X-linked myotubular myopathy Pathogenic:1 Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 08, 2013	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Feb 19, 2022	In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 158911). This variant has been observed in individual(s) with clinical features of MTM1-related conditions (PMID: 31541013). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 11 of the MTM1 gene. It does not directly change the encoded amino acid sequence of the MTM1 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.32
CADD	Pathogenic	30
DANN	Benign	0.87

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.71		Position offset: -47
DS_DL_spliceai		0.98		Position offset: -5

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

Publications

LitVar

Other links and lift over

dbSNP: rs587783769; hg19: chrX-149826505;