1-156135279-CCT-C

Position:

• chr1-156135279-CCT-C

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.908_909del​(p.Ser303CysfsTer27) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000657 in 152,246 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: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: LMNA NM_170707.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6 O:1
• Conservation: PhyloP100: 6.25

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 1-156135279-CCT-C is Pathogenic according to our data. Variant chr1-156135279-CCT-C is described in ClinVar as [Pathogenic]. Clinvar id is 66955.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-156135279-CCT-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMNA	NM_005572.4	c.908_909del	p.Ser303CysfsTer27	frameshift_variant	5/10	ENST00000677389.1
LMNA	NM_170707.4	c.908_909del	p.Ser303CysfsTer27	frameshift_variant	5/12	ENST00000368300.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMNA	ENST00000368300.9	c.908_909del	p.Ser303CysfsTer27	frameshift_variant	5/12	1	NM_170707.4	P1
LMNA	ENST00000677389.1	c.908_909del	p.Ser303CysfsTer27	frameshift_variant	5/10		NM_005572.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152246 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

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

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152246 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74382

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 04, 2017	- -
not provided, no classification provided	literature only	Epithelial Biology; Institute of Medical Biology, Singapore	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Sep 02, 2022	Segregated with a laminopathy phenotype in one large family with multiple relatives who had sinus bradycardia, atrioventricular arrhythmias, including atrial fibrillation, heart failure, and cardiac sudden death (Sparks et al., 2011); Not observed in large population cohorts (gnomAD); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 25948554, 12854972, 17605093, 21327842, 21691096, 29253866, 30078822) -

Dilated cardiomyopathy 1S Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen

May 01, 2016

- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 18, 2023

This sequence change creates a premature translational stop signal (p.Ser303Cysfs*27) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with arrhythmia, atrioventricular block, dilated cardiomyopathy, and/or limb-girdle muscular dystrophy (PMID: 17605093, 21691096). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 66955). For these reasons, this variant has been classified as Pathogenic. -

Dilated cardiomyopathy 1A Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Feb 08, 2013

- -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 07, 2022

The c.908_909delCT pathogenic mutation, located in coding exon 5 of the LMNA gene, results from a deletion of two nucleotides at nucleotide positions 908 to 909, causing a translational frameshift with a predicted alternate stop codon (p.S303Cfs*27). This alteration has been reported in individuals with dilated cardiomyopathy (DCM) with conduction defects, as well as in individuals with limb-girdle muscular dystrophy (LGMD) with DCM (MacLeod HM et al. BMC Med Genet, 2003 Jul;4:4; Antoniades L et al. J Interv Card Electrophysiol, 2007 Jun;19:1-7; Klauke B et al. PLoS One, 2017 Dec;12:e0189489; Nakajima K et al. Circ J, 2018 10;82:2707-2714). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
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

Publications

LitVar

Other links and lift over

dbSNP: rs59684335; hg19: chr1-156105070;