chr2-151540390-G-GT

Position:

• chr2-151540390-G-GT

Variant summary

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

The NM_001164508.2(NEB):​c.20845dupA​(p.Thr6949fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000837 in 1,434,136 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000084 (0 hom.)
• Consequence: NEB NM_001164508.2 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.67

Genes affected

NEB (HGNC:7720): (nebulin) This gene encodes nebulin, a giant protein component of the cytoskeletal matrix that coexists with the thick and thin filaments within the sarcomeres of skeletal muscle. In most vertebrates, nebulin accounts for 3 to 4% of the total myofibrillar protein. The encoded protein contains approximately 30-amino acid long modules that can be classified into 7 types and other repeated modules. Protein isoform sizes vary from 600 to 800 kD due to alternative splicing that is tissue-, species-,and developmental stage-specific. Of the 183 exons in the nebulin gene, at least 43 are alternatively spliced, although exons 143 and 144 are not found in the same transcript. Of the several thousand transcript variants predicted for nebulin, the RefSeq Project has decided to create three representative RefSeq records. Mutations in this gene are associated with recessive nemaline myopathy. [provided by RefSeq, Sep 2009]

LOC124906081 (HGNC:):

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 2-151540390-G-GT is Pathogenic according to our data. Variant chr2-151540390-G-GT is described in ClinVar as [Pathogenic]. Clinvar id is 551753.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NEB	NM_001164507.2	c.20845dupA	p.Thr6949fs	frameshift_variant	138/182	ENST00000427231.7	NP_001157979.2
NEB	NM_001164508.2	c.20845dupA	p.Thr6949fs	frameshift_variant	138/182	ENST00000397345.8	NP_001157980.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NEB	ENST00000397345.8	c.20845dupA	p.Thr6949fs	frameshift_variant	138/182	5	NM_001164508.2	ENSP00000380505.3
NEB	ENST00000427231.7	c.20845dupA	p.Thr6949fs	frameshift_variant	138/182	5	NM_001164507.2	ENSP00000416578.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000837 AC: 12 AN: 1434136 Hom.: 0 Cov.: 30 AF XY: 0.00000704 AC XY: 5 AN XY: 710482

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: 0.0000109

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nemaline myopathy 2 Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	3billion	Jan 03, 2022	Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant (PVS1_VS). The variant has been reported at least twice as pathogenic/likely pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000551753, PMID:25205138). It is not observed in the gnomAD v2.1.1 dataset (PM2_M). The variant has been reported to be in trans with a pathogenic variant (NM_001164508.2:c.24579G>A) as compound heterozygous at least one similarly affected unrelated individual (3billion dataset, PM3_M). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	May 19, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 13, 2023	This sequence change creates a premature translational stop signal (p.Thr6949Asnfs*16) in the NEB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in NEB are known to be pathogenic (PMID: 25205138). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with nemaline myopathy (PMID: 25205138). ClinVar contains an entry for this variant (Variation ID: 551753). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs1553695209; hg19: chr2-152396904;