1-156137666-C-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_170707.4(LMNA):c.1621C>T(p.Arg541Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000713 in 1,401,750 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R541G) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: LMNA NM_170707.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9 O:1
• Conservation: PhyloP100: 0.895

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 17 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 14 uncertain in NM_170707.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-156137667-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 66860.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, LMNA
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.918
• PP5: Variant 1-156137666-C-T is Pathogenic according to our data. Variant chr1-156137666-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 48046.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-156137666-C-T is described in Lovd as [Pathogenic]. Variant chr1-156137666-C-T is described in Lovd as [Likely_pathogenic]. Variant chr1-156137666-C-T is described in Lovd as [Likely_pathogenic]. Variant chr1-156137666-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMNA	NM_170707.4	c.1621C>T	p.Arg541Cys	missense_variant	10/12	ENST00000368300.9
LMNA	NM_005572.4	c.1621C>T	p.Arg541Cys	missense_variant	10/10	ENST00000677389.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMNA	ENST00000368300.9	c.1621C>T	p.Arg541Cys	missense_variant	10/12	1	NM_170707.4	P1
LMNA	ENST00000677389.1	c.1621C>T	p.Arg541Cys	missense_variant	10/10		NM_005572.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.13e-7 AC: 1 AN: 1401750 Hom.: 0 Cov.: 31 AF XY: 0.00000145 AC XY: 1 AN XY: 691498

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: 9.26e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:4 Other:1

not provided, no classification provided	literature only	Epithelial Biology; Institute of Medical Biology, Singapore	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 14, 2022	Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies examined the effect of p.(R541C) on the nuclear envelope in cultured skin fibroblasts and reported an absence or significant decrease in lamin B1 expression, as well as a lobulated nuclear envelope, in comparison to controls (Muchir et al., 2004); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18031519, 31912959, 30847666, 24375749, 24503780, 19167105, 24623722, 19933576, 23702046, 27532257, 15724423, 22464770, 30165862, 29952368, 31383942, 32458740, 31447099, 32914734, 30975432, 33250842, 14675861, 10939567, 15372542) -
Pathogenic, no assertion criteria provided	provider interpretation	Stanford Center for Inherited Cardiovascular Disease, Stanford University	Jun 06, 2016	We consider this variant to be very likely pathogenic and we do feel it is suitable for assessing risk in healthy relatives ("predictive genetic testing"). The reasons for this classification include strong case data, including de novo occurrence and some segregation data in two families; functional studies supporting pathogenicity; and multiple other reported disease causing variants affecting the same codon. We have seen this variant in a patient with DCM. Testing was performed by Invitae. The variant has been seen in at least 6 unrelated cases of dilated cardiomyopathy and/or arrhythmia (not including this patient's family). Forissier J et al., 2003 reported the R541C variant in a father and daughter with DCM and arrhythmias. R541C occurred de novo in the father in the context of a negative family history in preceding generations. Muchir et al., 2004 reported to be a 29 year-old with DCM and conduction system disease. They performed functional studied in cultured skin fibroblasts and reported an absence or significant decrease in lamin B1 expression and a lobulated nuclear envelope with the R541C variant compared to controls. Hookana et al., 2008 reported the R541C variant in a mother with a history of an aborted SCD and LV hypokinesia and thinning and daughter who died suddenly and was found to have localize LV thinning and fibrosis. The variant was found to have occurred de novo in the mother in the context of a negative family history. Saj M et al., 2010 reported a 19 year old with LV DCM s/p ICD implantation and aborted VFib cardiac arrests, with a family history of SCD. Pugh et al., 2014 reported R541C in two individuals with DCM, one of which also carried a mutation in the LDB3 gene, per the LMM ClinVar entry. Other variants at the same codon (R541H, R541G, R541P, R541S) have been reported in association with dilated cardiomyopathy and other laminopathies, supporting the hypothesis that this codon occurs at a functionally important location in the protein. Per the Invitae report, "This sequence change replaces arginine with cysteine at codon 541 of the LMNA protein (p.Arg541Cys). The arginine residue is highly conserved and there is a large physicochemical difference between arginine and cysteine." Please note that the average coverage at this site in ExAC is poor: The mean depth is ~16x, the median depth is 4x, and ~95% of people have ~1x coverage, with ~40% having 5x coverage. The variant was reported online in 2 of 10,695 individuals in the Exome Aggregation Consortium dataset (http://exac.broadinstitute.org/), which currently includes variant calls on ~64,000 individuals of European, African, Latino and Asian descent (as of 6/6/2016). Specifically, the variant was observed in 2 of 4,568 non-Finnish European people. The phenotype of those individuals is not publicly available. The dataset is comprised of multiple cohorts, some of which were recruited from the general population, others were enriched for common cardiovascular disease. -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 16, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2023	LMNA: PM2, PM5, PP1:Moderate, PS4:Moderate, PP4, PS3:Supporting -

Dilated cardiomyopathy 1A Pathogenic:2

Likely pathogenic, criteria provided, single submitter	curation	SIB Swiss Institute of Bioinformatics	May 31, 2018	This variant is interpreted as a Likely Pathogenic, for Dilated cardiomyopathy, in Autosomal Dominant manner. The following ACMG Tag(s) were applied: PP3 => Multiple lines of computational evidence support a deleterious effect on the gene or gene product. PM2 => Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium. PM1 => Located in a mutational hot spot and/or critical and well-established functional domain (e.g., active site of an enzyme) without benign variation (PMID:18035086,16061563,18564364,21085127). PS3 => Well-established functional studies show a deleterious effect (PMID:15372542). -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Aug 27, 2015	- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 09, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 541 of the LMNA protein (p.Arg541Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with cardiac arrest and left ventricular fibrosis and dilated cardiomyopathy (PMID: 14675861, 15724423, 18031519, 22464770, 24503780, 27532257). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 48046). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt LMNA protein function with a positive predictive value of 95%. This variant disrupts the p.Arg541 amino acid residue in LMNA. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22186027, 24623722). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Primary dilated cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Apr 06, 2018

The p.Arg541Cys variant in LMNA has been identified in 6 individuals with DCM (F orissier 2003, Muchir 2004, Saj 2009, LMM data) and in one individual with sudde n cardiac death (Hookana 2008), occurring de novo in 2 cases (paternity confirme d). It was also shown to segregate with disease in 5 affected relatives from 4 f amilies (Forissier 2003, Hookana 2008, LMM data). It was absent from large popul ation studies. This variant has been shown to cause nuclear lamina abnormalities (Muchir 2004). Computational prediction tools and conservation analysis suggest that this variant may impact the protein and additional variants involving this amino acid, p.Arg541Ser and p.Arg541His, have been associated with DCM. In summ ary, this variant meets our criteria to be classified as pathogenic based upon c ase observations, de novo occurrences, segregation studies, absence from control s, and functional evidence. ACMG/AMP Criteria applied: PM6_Strong; PM2; PM5; PS4 _Moderate; PP1_Moderate; PP3. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 01, 2022

The p.R541C pathogenic mutation (also known as c.1621C>T), located in coding exon 10 of the LMNA gene, results from a C to T substitution at nucleotide position 1621. The arginine at codon 541 is replaced by cysteine, an amino acid with highly dissimilar properties. This mutation was reported in a Moroccan family with dilated cardiomyopathy (DCM), and co-segregation was observed in several affected family members (Adadi N et al. Anatol J Cardiol, 2018 Jul;20:65-68). This mutation has been associated with severe ventricular arrhythmia, left ventricular wall motion abnormalities, dilated cardiomyopathy (DCM) with significant left ventricular segmental contractility defects, and sudden cardiac death (Forissier JF et al. Eur. J. Heart Fail., 2003 Dec;5:821-5; Hookana E et al. J. Cardiovasc. Electrophysiol., 2008 Jul;19:743-7; Saj M et al. Int. J. Cardiol., 2010 Oct;144:e51-3). The mutation was shown to be associated with abnormal nuclear envelop folding in two independent studies (Muchir A et al. Muscle Nerve, 2004 Oct;30:444-50; Hookana E et al, 2008). Additionally, alterations at the same amino acid position, p.R541S (Sylvius N et al. J. Med. Genet., 2005 Aug;42:639-47), p.R541G (Maek LA et al. J. Hum. Genet., 2011 Jan;56:83-6), p.R541P (van Tintelen JP et al. Am. Heart J., 2007 Dec;154:1130-9), and p.R541H (Rudenskaya GE et al. Clin. Genet., 2008 Aug;74:127-33) have also been reported in families with cardiomyopathy. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
CardioboostCm	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
Cadd	Pathogenic	31
Dann	Pathogenic	1.0
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D;D
M_CAP	Pathogenic	0.74	D
MetaRNN	Pathogenic	0.92	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M;.;M;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-6.6	D;.;D;D;D;D;D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;.;D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D;D
Polyphen		1.0	D;.;D;.;.;D;.
Vest4		0.83
MutPred		0.73		Gain of methylation at K542 (P = 0.0127);.;Gain of methylation at K542 (P = 0.0127);Gain of methylation at K542 (P = 0.0127);.;.;.;
MVP		0.98
MPC		1.3
ClinPred		1.0	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.78
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs56984562; hg19: chr1-156107457;