X-32699107-T-G

Variant names:

• chrX-32699107-T-G
• rs757088996
• NM_004006.3:c.831+5A>C

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BS2_Supporting

The NM_004006.3(DMD):​c.831+5A>C variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000275 in 1,092,497 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 2 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000027 (0 hom. 2 hem.)
• Consequence: DMD NM_004006.3 splice_region, intron
• Scores: Splicing: ADA: 0.0001253
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 0.0580
• Publications: 0 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: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.75).
• BS2: High Hemizygotes in GnomAdExome4 at 2 XL,AD geneVariant has number of hemizygotes lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DMD	NM_004006.3	c.831+5A>C		splice_region_variant, intron_variant	Intron 8 of 78	ENST00000357033.9	NP_003997.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DMD	ENST00000357033.9	c.831+5A>C		splice_region_variant, intron_variant	Intron 8 of 78	1	NM_004006.3	ENSP00000354923.3

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD2 exomes AF: 0.0000109 AC: 2 AN: 182711 AF XY: 0.0000148

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000246

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000275 AC: 3 AN: 1092497 Hom.: 0 Cov.: 29 AF XY: 0.00000558 AC XY: 2 AN XY: 358439

African (AFR) AF: 0.00 AC: 0 AN: 26267

American (AMR) AF: 0.00 AC: 0 AN: 35191

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19324

East Asian (EAS) AF: 0.00 AC: 0 AN: 30146

South Asian (SAS) AF: 0.00 AC: 0 AN: 54011

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40514

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4111

European-Non Finnish (NFE) AF: 0.00000358 AC: 3 AN: 837055

Other (OTH) AF: 0.00 AC: 0 AN: 45878

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

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

Dec 24, 2018

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Duchenne muscular dystrophy Uncertain:1

Dec 04, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Nucleotide substitutions within 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 is not likely to affect RNA splicing, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with DMD-related disease. This variant is present in population databases (rs757088996, ExAC 0.002%). This sequence change falls in intron 8 of the DMD gene. It does not directly change the encoded amino acid sequence of the DMD protein, but it affects a nucleotide within the consensus splice site of the intron. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.75
CADD	Benign	5.2
DANN	Benign	0.72
PhyloP100		0.058
Mutation Taster		=94/6	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00013
dbscSNV1_RF	Benign	0.016
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: rs757088996; hg19: chrX-32717224;