rs1553266024

Variant names:

• chr1-156136975-CT-C
• rs1553266024
• NM_170707.4:c.1436delT

Variant summary

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

The NM_170707.4(LMNA):​c.1436delT​(p.Leu479ArgfsTer11) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L479L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.81

Genes affected

LMNA (HGNC:6636): (lamin A/C) The protein encoded by this gene is part of the nuclear lamina, a two-dimensional matrix of proteins located next to the inner nuclear membrane. The lamin family of proteins make up the matrix and are highly conserved in evolution. During mitosis, the lamina matrix is reversibly disassembled as the lamin proteins are phosphorylated. Lamin proteins are thought to be involved in nuclear stability, chromatin structure and gene expression. Vertebrate lamins consist of two types, A and B. Alternative splicing results in multiple transcript variants. Mutations in this gene lead to several diseases: Emery-Dreifuss muscular dystrophy, familial partial lipodystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy, Charcot-Marie-Tooth disease, and Hutchinson-Gilford progeria syndrome. [provided by RefSeq, May 2022]

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 1-156136975-CT-C is Pathogenic according to our data. Variant chr1-156136975-CT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 476823.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
LMNA	NM_170707.4	c.1436delT	p.Leu479ArgfsTer11	frameshift_variant	Exon 8 of 12	ENST00000368300.9	NP_733821.1
LMNA	NM_005572.4	c.1436delT	p.Leu479ArgfsTer11	frameshift_variant	Exon 8 of 10	ENST00000677389.1	NP_005563.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LMNA	ENST00000368300.9	c.1436delT	p.Leu479ArgfsTer11	frameshift_variant	Exon 8 of 12	1	NM_170707.4	ENSP00000357283.4
LMNA	ENST00000677389.1	c.1436delT	p.Leu479ArgfsTer11	frameshift_variant	Exon 8 of 10		NM_005572.4	ENSP00000503633.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Feb 28, 2018

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A variant that is likely pathogenic has been identified in the LMNA gene. The c.1436delT variant hasnot been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The c.1436delT variant causes a frameshift starting with codon Leucine 479, changes this amino acid to an Arginine residue and creates a premature Stop codon at position 11 of the new reading frame, denoted p.Leu479ArgfsX11. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.1436delT variant is not observed in large population cohorts (Lek et al., 2016). Therefore, this variant is likelypathogenic; however, the possibility that it is benign cannot be excluded. -

Feb 03, 2021

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Jul 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 476823). This variant has not been reported in the literature in individuals affected with LMNA-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Leu479Argfs*11) in the LMNA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in LMNA are known to be pathogenic (PMID: 18585512, 18926329). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1553266024; hg19: chr1-156106766;