rs777510517

Positions:

• chrX-31178669-G-A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BS2

The NM_004006.3(DMD):​c.10223C>T​(p.Thr3408Ile) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000366 in 1,091,477 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 15 hemizygotes in GnomAD. 2/3 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: 22)
  • Exomes 𝑓: 0.000037 (0 hom. 15 hem.)
• Consequence: DMD NM_004006.3 missense, splice_region
• Scores: Splicing: ADA: 0.9848
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7 B:1
• Conservation: PhyloP100: 9.60

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]

DMD (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• BS2: High Hemizygotes in GnomAdExome4 at 15 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DMD	NM_004006.3	c.10223C>T	p.Thr3408Ile	missense_variant, splice_region_variant	70/79	ENST00000357033.9	NP_003997.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DMD	ENST00000357033.9	c.10223C>T	p.Thr3408Ile	missense_variant, splice_region_variant	70/79	1	NM_004006.3	ENSP00000354923.3

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD3 exomes AF: 0.0000440 AC: 8 AN: 181746 Hom.: 0 AF XY: 0.0000451 AC XY: 3 AN XY: 66496

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000366

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000723

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000741

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000366 AC: 40 AN: 1091477 Hom.: 0 Cov.: 30 AF XY: 0.0000419 AC XY: 15 AN XY: 358073

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000285

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000666

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000430

Gnomad4 OTH exome AF: 0.0000218

GnomAD4 genome Cov.: 22

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000264

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:4

Uncertain significance, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 17, 2019	- -
Uncertain significance, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Feb 07, 2023	Available data are insufficient to determine the clinical significance of the variant at this time. The frequency of this variant in the general population is higher than would generally be expected for pathogenic variants in this gene. (http://gnomad.broadinstitute.org) Computational tools disagree on the variant's effect on normal protein function. According to published research, less than 2% of dystrophin-related disease is due to missense mutation (Flanigan, et al. 2009. Hum Mutat 30: 1657-66. PMID: 19937601). -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 01, 2015

The p.Thr340Met variant in DMD (NM_004019.2; historical transcript name dp40) ha s not been previously reported in individuals with cardiomyopathy, but has been identified in 2/47526 European chromosomes by the Exome Aggregation Consortium ( ExAC, http://exac.broadinstitute.org). This variant also results in a threonine to isoleucine change at position 3408 (p.Thr3408Ile) in the muscle-specific DMD transcript NM_004006.2 (historical transcript name dp427m). In this transcript, this variant is located in the last three bases of the exon, which is part of th e 5? splice region. Computational tools do not suggest an impact to splicing; ho wever, they do suggest that this variant may impact the protein, though this inf ormation is not predictive enough to determine pathogenicity. In summary, the cl inical significance of the p.Thr340Met variant is uncertain. -

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

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Jul 16, 2019

- -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 11, 2024

The c.10223C>T variant (also known as p.T3408I), located in coding exon 70 of the DMD gene, results from a C to T substitution at nucleotide position 10223. The amino acid change results in threonine to isoleucine at codon 3408, an amino acid with similar properties. However, this change occurs in the last base pair of coding exon 70, which makes it likely to have some effect on normal mRNA splicing. Based on data from gnomAD, the T allele has an overall frequency of 0.0044% (8/181746) total alleles studied, with 3 hemizygote(s) observed. The highest observed frequency was 0.0074% (6/80936) of European (non-Finnish) alleles. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Duchenne muscular dystrophy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 29, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.50
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	.;T;T;.;T;.;.;.;T;.
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.89	D;.;.;D;.;D;D;D;.;D
M_CAP	Pathogenic	0.90	D
MetaRNN	Uncertain	0.69	D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.59	D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-4.5	D;.;D;.;D;.;D;D;D;D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.016	D;.;D;.;D;.;D;D;D;D
Sift4G	Benign	0.064	T;D;D;D;D;D;D;T;D;T
Polyphen		0.81, 1.0	.;.;P;.;D;.;.;.;P;.
Vest4		0.87
MutPred		0.34		.;.;.;.;.;.;Gain of loop (P = 0.0435);.;.;.;
MVP		0.98
MPC		0.069
ClinPred		0.39	T
GERP RS		5.0
gMVP		0.66

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.98
dbscSNV1_RF	Pathogenic	0.77
SpliceAI score (max)		0.010		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: rs777510517; hg19: chrX-31196786;