NM_170707.4:c.80C>T

Variant names:

• chr1-156114998-C-T
• rs863225270
• NM_170707.4:c.80C>T

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PP3 PP5_Very_Strong

The NM_170707.4(LMNA):​c.80C>T​(p.Thr27Ile) variant causes a missense change. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T27S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 4.93
• Publications: 2 publications found

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]

LMNA Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1A

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet
• familial partial lipodystrophy, Dunnigan type

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• Hutchinson-Gilford progeria syndrome

  Inheritance: AD, SD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• restrictive dermopathy 2

  Inheritance: AR, AD Classification: DEFINITIVE, LIMITED Submitted by: G2P
• Emery-Dreifuss muscular dystrophy 2, autosomal dominant

  Inheritance: SD, AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• atrioventricular block

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• heart-hand syndrome, Slovenian type

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, G2P
• Charcot-Marie-Tooth disease type 2B1

  Inheritance: AR, AD Classification: STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: G2P, Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae)
• Emery-Dreifuss muscular dystrophy 3, autosomal recessive

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• mandibuloacral dysplasia with type A lipodystrophy

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• atrial fibrillation

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• atypical Werner syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal dominant Emery-Dreifuss muscular dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• congenital muscular dystrophy due to LMNA mutation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• lethal restrictive dermopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• LMNA-related cardiocutaneous progeria syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive Emery-Dreifuss muscular dystrophy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy-hypergonadotropic hypogonadism syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal semi-dominant severe lipodystrophic laminopathy

  Inheritance: SD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 18 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 21 uncertain in NM_170707.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.751
• PP5: Variant 1-156114998-C-T is Pathogenic according to our data. Variant chr1-156114998-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 804298.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.80C>T	p.Thr27Ile	missense_variant	Exon 1 of 12	ENST00000368300.9	NP_733821.1
LMNA	NM_005572.4	c.80C>T	p.Thr27Ile	missense_variant	Exon 1 of 10	ENST00000677389.1	NP_005563.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LMNA	ENST00000368300.9	c.80C>T	p.Thr27Ile	missense_variant	Exon 1 of 12	1	NM_170707.4	ENSP00000357283.4
LMNA	ENST00000677389.1	c.80C>T	p.Thr27Ile	missense_variant	Exon 1 of 10		NM_005572.4	ENSP00000503633.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Oct 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 27 of the LMNA protein (p.Thr27Ile). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with limb-girdle muscular dystrophy (PMID: 25256213). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 804298). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt LMNA protein function with a positive predictive value of 95%. This variant disrupts the p.Thr27 amino acid residue in LMNA. Other variant(s) that disrupt this residue have been observed in individuals with LMNA-related conditions (PMID: 25256213; internal data), which suggests that this may be a clinically significant amino acid residue. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Congenital muscular dystrophy due to LMNA mutation;C5979868:Dilated cardiomyopathy 1A Pathogenic:1

Sep 12, 2019

Cardiogenetic Laboratory, Instituto Murciano de Investigación Biosanitaria

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
CardioboostCm	Benign	0.079
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	.;.;.;D;.
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.81	T;T;T;T;T
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.75	D;D;D;D;D
MetaSVM	Uncertain	0.14	D
MutationAssessor	Benign	1.7	L;.;L;L;L
PhyloP100		4.9
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.6	D;D;D;D;D
REVEL	Uncertain	0.55
Sift	Uncertain	0.0010	D;D;D;D;D
Sift4G	Uncertain	0.010	D;D;D;D;D
Polyphen		0.66	P;.;D;P;.
Vest4		0.82
MutPred		0.25		Loss of phosphorylation at T27 (P = 0.0346);Loss of phosphorylation at T27 (P = 0.0346);Loss of phosphorylation at T27 (P = 0.0346);Loss of phosphorylation at T27 (P = 0.0346);Loss of phosphorylation at T27 (P = 0.0346);
MVP		0.86
MPC		1.2
ClinPred		0.98	D
GERP RS		4.8
PromoterAI		0.064	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.3
Varity_R		0.78
gMVP		0.97
Mutation Taster		=0/100	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs863225270; hg19: chr1-156084789; COSMIC: COSV61542386; COSMIC: COSV61542386;