rs58978449

Variant names:

• chr1-156134942-TAAG-T
• rs58978449
• NM_170707.4:c.781_783delAAG

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1 PM2 PM4_Supporting PP5_Very_Strong

The NM_170707.4(LMNA):​c.781_783delAAG​(p.Lys261del) variant causes a conservative inframe deletion 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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 conservative_inframe_deletion
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 7.22

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 13 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_170707.4
• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_170707.4. Strenght limited to Supporting due to length of the change: 1aa.
• PP5: Variant 1-156134942-TAAG-T is Pathogenic according to our data. Variant chr1-156134942-TAAG-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 48080.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-156134942-TAAG-T is described in Lovd as [Pathogenic]. Variant chr1-156134942-TAAG-T is described in Lovd as [Likely_pathogenic]. Variant chr1-156134942-TAAG-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LMNA	NM_170707.4	c.781_783delAAG	p.Lys261del	conservative_inframe_deletion	Exon 4 of 12	ENST00000368300.9	NP_733821.1
LMNA	NM_005572.4	c.781_783delAAG	p.Lys261del	conservative_inframe_deletion	Exon 4 of 10	ENST00000677389.1	NP_005563.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LMNA	ENST00000368300.9	c.781_783delAAG	p.Lys261del	conservative_inframe_deletion	Exon 4 of 12	1	NM_170707.4	ENSP00000357283.4
LMNA	ENST00000677389.1	c.781_783delAAG	p.Lys261del	conservative_inframe_deletion	Exon 4 of 10		NM_005572.4	ENSP00000503633.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2 Other:1

Apr 27, 2017

Eurofins Ntd Llc (ga)

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 04, 2018

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.781_783delAAG pathogenic variant has been reported in multiple individuals with autosomal dominant Emery Dreifuss muscular dytrophy, including as a de novo change (Bonne et al., 2000, Rudenskaya et al., 2008, Rankin et al., 2006). The c.781_783delAAG variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The c.781_783delAAG variant results in an in-frame deletion of a single Lysine residue, denoted p.Lys261del. This varaint occurs at a position that is conserved across species. Therefore, based on the currently available information, we interpret c.781_783delAAG as a pathogenic variant, and its presence is consistent with an LMNA-related disorder in this individual. -

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Epithelial Biology; Institute of Medical Biology, Singapore

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Mar 11, 2023

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. This variant, c.781_783del, results in the deletion of 1 amino acid(s) of the LMNA protein (p.Lys261del), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individuals with autosomal dominant LMNA-related conditions (PMID: 10908904, 10939567, 11503164, 22068161). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 48080). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this variant affects LMNA function (PMID: 22068161). -

Primary dilated cardiomyopathy Pathogenic:1

May 18, 2011

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Lys261del variant has been reported in 2 individuals with a clinical diagnos is and family history of Emery-Dreifuss muscular dystrophy. The variant was abse nt from over 680 control chromosomes, supporting a pathogenic role (Bonne 2000, Brown 2001, Felice 2000). In addition, our laboratory has detected this variant in one individual whose clinical features were consistent with those of the prev iously published patients, further increasing the likelihood that this variant i s pathogenic. -

Cardiovascular phenotype Pathogenic:1

Apr 20, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.781_783delAAG variant (also known as p.K261del) is located in coding exon 4 of the LMNA gene. This variant results from an in-frame AAG deletion at nucleotide positions 781 to 783. This results in the in-frame deletion of a lysine at codon 261. This alteration has been reported in subjects with LMNA-associated disease and has been reported as de novo (Felice KJ et al. Neurology, 2000 Jul;55:275-80; Bonne G et al. Ann Neurol, 2000 Aug;48:170-80; Brown CA et al. Am J Med Genet, 2001 Sep;102:359-67; Ben Yaou R et al. Brain Commun, 2021 Jul;3:fcab075). This variant is also considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs58978449; hg19: chr1-156104733;