rs886043260

chr1-156135227-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_170707.4(LMNA):c.851T>C(p.Leu284Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L284L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 2.88

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_170707.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, LMNA
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.848
• PP5: Variant 1-156135227-T-C is Pathogenic according to our data. Variant chr1-156135227-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 285938.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMNA	NM_170707.4	c.851T>C	p.Leu284Pro	missense_variant	5/12	ENST00000368300.9
LMNA	NM_005572.4	c.851T>C	p.Leu284Pro	missense_variant	5/10	ENST00000677389.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMNA	ENST00000368300.9	c.851T>C	p.Leu284Pro	missense_variant	5/12	1	NM_170707.4	P1
LMNA	ENST00000677389.1	c.851T>C	p.Leu284Pro	missense_variant	5/10		NM_005572.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Aug 16, 2022

For these reasons, this variant has been classified as Pathogenic. 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. ClinVar contains an entry for this variant (Variation ID: 285938). This missense change has been observed in individual(s) with autosomal dominant limb-girdle muscular dystrophy and cardiomyopathy (PMID: 22491857). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 284 of the LMNA protein (p.Leu284Pro). -

Congenital muscular dystrophy due to LMNA mutation Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

3billion

May 22, 2022

The variant is not observed in the gnomAD v2.1.1 dataset. Missense changes are a common disease-causing mechanism. Functional studies provide supporting evidence of the variant having a damaging effect on the gene or gene product (PMID: 22491857). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.73; 3Cnet: 0.87). The variant has been previously reported as de novo in a similarly affected individual (PMID: 22491857). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Feb 18, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
CardioboostCm	Uncertain	0.27
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
Cadd	Pathogenic	26
Dann	Uncertain	1.0
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.45	D
MutationAssessor	Uncertain	2.8	M;.;M;M;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-2.2	N;N;N;N;N;N;N;N
REVEL	Pathogenic	0.73
Sift	Benign	0.20	T;T;T;T;T;T;T;T
Sift4G	Benign	0.20	T;T;T;T;T;T;T;T
Polyphen		0.89	P;.;P;P;.;.;P;.
Vest4		0.88
MutPred		0.61		Loss of stability (P = 0.017);Loss of stability (P = 0.017);Loss of stability (P = 0.017);Loss of stability (P = 0.017);Loss of stability (P = 0.017);.;.;.;
MVP		0.97
MPC		2.2
ClinPred		0.89	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Varity_R		0.62
gMVP		0.99

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: rs886043260; hg19: chr1-156105018;