chrX-32644238-T-C

Variant names:

• chrX-32644238-T-C
• rs34155804
• NM_004006.3:c.1225A>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_004006.3(DMD):​c.1225A>G​(p.Thr409Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000182 in 1,097,603 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T409S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 1 hem.)
• Consequence: DMD NM_004006.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0270
• Publications: 6 publications found

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 Gene-Disease associations (from GenCC):

• Becker muscular dystrophy

  Inheritance: XL Classification: DEFINITIVE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet
• dilated cardiomyopathy 3B

  Inheritance: XL Classification: DEFINITIVE Submitted by: Ambry Genetics
• Duchenne and Becker muscular dystrophy

  Inheritance: XL Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• Duchenne muscular dystrophy

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, Orphanet
• progressive muscular dystrophy

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• non-syndromic X-linked intellectual disability

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• symptomatic form of muscular dystrophy of Duchenne and Becker in female carriers

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.073453546).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DMD	NM_004006.3	c.1225A>G	p.Thr409Ala	missense_variant	Exon 11 of 79	ENST00000357033.9	NP_003997.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DMD	ENST00000357033.9	c.1225A>G	p.Thr409Ala	missense_variant	Exon 11 of 79	1	NM_004006.3	ENSP00000354923.3

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000182 AC: 2 AN: 1097603 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 1 AN XY: 363035

African (AFR) AF: 0.00 AC: 0 AN: 26392

American (AMR) AF: 0.00 AC: 0 AN: 35190

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19372

East Asian (EAS) AF: 0.00 AC: 0 AN: 30193

South Asian (SAS) AF: 0.00 AC: 0 AN: 54136

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40494

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4135

European-Non Finnish (NFE) AF: 0.00000238 AC: 2 AN: 841616

Other (OTH) AF: 0.00 AC: 0 AN: 46075

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Duchenne muscular dystrophy Uncertain:1

Aug 26, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine with alanine at codon 409 of the DMD protein (p.Thr409Ala). The threonine residue is weakly conserved and there is a small physicochemical difference between threonine and alanine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with DMD-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The alanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.068
BayesDel_addAF	Benign	-0.49	T
BayesDel_noAF	Benign	-0.94
CADD	Benign	5.9
DANN	Benign	0.97
DEOGEN2	Benign	0.22	.;T;.;.;T
FATHMM_MKL	Benign	0.072	N
LIST_S2	Benign	0.42	T;.;T;T;T
M_CAP	Benign	0.0055	T
MetaRNN	Benign	0.073	T;T;T;T;T
MetaSVM	Benign	-1.0	T
PhyloP100		-0.027
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-0.010	.;N;.;N;N
REVEL	Benign	0.038
Sift	Benign	0.22	.;T;.;T;T
Sift4G	Benign	0.51	T;T;T;T;T
Polyphen		0.0	.;B;.;.;B
Vest4		0.12
MutPred		0.41		.;.;Loss of methylation at K411 (P = 0.1453);Loss of methylation at K411 (P = 0.1453);.;
MVP		0.44
MPC		0.017
ClinPred		0.026	T
GERP RS		0.29
gMVP		0.10
Mutation Taster		=96/4	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs34155804; hg19: chrX-32662355;