NM_001164507.2:c.9726_9727insAT

Variant names:

• chr2-151629643-G-GAT
• rs1553934562
• NM_001164507.2:c.9726_9727insAT

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001164507.2(NEB):​c.9726_9727insAT​(p.Leu3243IlefsTer62) variant causes a frameshift, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,664 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T3242T) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NEB NM_001164507.2 frameshift, splice_region
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 0.357
• Publications: 0 publications found

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]

NEB Gene-Disease associations (from GenCC):

• nemaline myopathy 2

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, G2P, Ambry Genetics
• childhood-onset nemaline myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• intermediate nemaline myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• typical nemaline myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• lethal multiple pterygium syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• severe congenital nemaline myopathy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 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 2-151629643-G-GAT is Pathogenic according to our data. Variant chr2-151629643-G-GAT is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 465655.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NEB	NM_001164507.2	c.9726_9727insAT	p.Leu3243IlefsTer62	frameshift_variant, splice_region_variant	Exon 68 of 182	ENST00000427231.7	NP_001157979.2
NEB	NM_001164508.2	c.9726_9727insAT	p.Leu3243IlefsTer62	frameshift_variant, splice_region_variant	Exon 68 of 182	ENST00000397345.8	NP_001157980.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NEB	ENST00000397345.8	c.9726_9727insAT	p.Leu3243IlefsTer62	frameshift_variant, splice_region_variant	Exon 68 of 182	5	NM_001164508.2	ENSP00000380505.3
NEB	ENST00000427231.7	c.9726_9727insAT	p.Leu3243IlefsTer62	frameshift_variant, splice_region_variant	Exon 68 of 182	5	NM_001164507.2	ENSP00000416578.2
NEB	ENST00000409198.5	c.8997_8998insAT	p.Leu3000IlefsTer62	frameshift_variant, splice_region_variant	Exon 65 of 150	5		ENSP00000386259.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460664 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 726674

African (AFR) AF: 0.00 AC: 0 AN: 33454

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26106

East Asian (EAS) AF: 0.00 AC: 0 AN: 39652

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53328

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111062

Other (OTH) AF: 0.0000166 AC: 1 AN: 60344

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nemaline myopathy Pathogenic:1

Mar 17, 2025

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The p.Leu3243IlefsTer62 variant in NEB has not been previously reported in the literature in individuals with nemaline myopathy, but has been identified in 0.002% (1/62450) of remaining chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs1553934562). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (Variation ID: 465655) and has been interpreted as pathogenic by Invitae. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 3243 and leads to a premature termination codon 62 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the NEB gene is an established disease mechanism in autosomal recessive nemaline myopathy. In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive nemaline myopathy. ACMG/AMP Criteria applied: PVS1, PM2_supporting (Richards 2015). -

Nemaline myopathy 2 Pathogenic:1

Aug 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 465655). This sequence change creates a premature translational stop signal (p.Leu3243Ilefs*62) 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 variant has not been reported in the literature in individuals affected with NEB-related conditions. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.36
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1553934562; hg19: chr2-152486157;