X-32365049-G-A

Position:

• chrX-32365049-G-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_004006.3(DMD):​c.4996C>T​(p.Arg1666Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000911 in 1,097,807 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 22)
  • Exomes 𝑓: 9.1e-7 (0 hom. 0 hem.)
• Consequence: DMD NM_004006.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:9
• Conservation: PhyloP100: 1.39

Genes affected

DMD (HGNC:2928): (dystrophin) This gene spans a genomic range of greater than 2 Mb and encodes a large protein containing an N-terminal actin-binding domain and multiple spectrin repeats. The encoded protein forms a component of the dystrophin-glycoprotein complex (DGC), which bridges the inner cytoskeleton and the extracellular matrix. Deletions, duplications, and point mutations at this gene locus may cause Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), or cardiomyopathy. Alternative promoter usage and alternative splicing result in numerous distinct transcript variants and protein isoforms for this gene. [provided by RefSeq, Dec 2016]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-32365049-G-A is Pathogenic according to our data. Variant chrX-32365049-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 94646.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-32365049-G-A is described in Lovd as [Pathogenic]. Variant chrX-32365049-G-A is described in Lovd as [Pathogenic]. Variant chrX-32365049-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DMD	NM_004006.3	c.4996C>T	p.Arg1666Ter	stop_gained	35/79	ENST00000357033.9	NP_003997.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DMD	ENST00000357033.9	c.4996C>T	p.Arg1666Ter	stop_gained	35/79	1	NM_004006.3	ENSP00000354923	P4

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome AF: 9.11e-7 AC: 1 AN: 1097807 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 363277

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000217

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Duchenne muscular dystrophy Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Genomic Research Center, Shahid Beheshti University of Medical Sciences	May 03, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The frame shift variant c.4996C>T(p.Arg1666Ter) has been reported previously in patients affected with Duchenne muscular dystrophy (Magri F et al., 2011; Stockley TL et al., 2006). This sequence change creates a premature translational stop signal (p.Arg1666) in the DMD gene. It is expected to result in an absent or disrupted protein product. The nucleotide change in DMD is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The c.4996C>T(p.Arg1666Ter) variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. This variant is predicted to cause loss of normal protein function through protein truncation. Loss of function variants have been previously reported to be disease causing. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 19, 2023	This sequence change creates a premature translational stop signal (p.Arg1666*) in the DMD gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in DMD are known to be pathogenic (PMID: 16770791, 25007885). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with Duchenne muscular dystrophy (PMID: 11524473, 15351422, 17253928, 19760747, 19959795, 21396098). ClinVar contains an entry for this variant (Variation ID: 94646). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 31, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Aug 22, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Feb 01, 2017	- -

Qualitative or quantitative defects of dystrophin Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jul 21, 2023

Variant summary: DMD c.4996C>T (p.Arg1666X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Variants downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 183156 control chromosomes (gnomAD). c.4996C>T has been reported in the literature in individuals affected with Dystrophinopathies (example: Tuffery-Giraud_2004, Spitali_2009, and Magri_2011). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Duchenne muscular dystrophy;C0878544:Cardiomyopathy;C0917713:Becker muscular dystrophy;na:Dystrophin deficiency Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

May 24, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	33
DANN	Uncertain	0.99
FATHMM_MKL	Uncertain	0.86	D
MutationTaster	Benign	1.0	A;A
Vest4		0.98
GERP RS		2.4

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs398123973; hg19: chrX-32383166;