rs1553261977

chr1-156115159-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP2 PP3_Strong PP5

The NM_170707.4(LMNA):c.241T>C(p.Tyr81His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y81C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 8.02

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 10 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 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, 0.97
• PP5: Variant 1-156115159-T-C is Pathogenic according to our data. Variant chr1-156115159-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 543218.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMNA	NM_170707.4	c.241T>C	p.Tyr81His	missense_variant	1/12	ENST00000368300.9
LMNA	NM_005572.4	c.241T>C	p.Tyr81His	missense_variant	1/10	ENST00000677389.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMNA	ENST00000368300.9	c.241T>C	p.Tyr81His	missense_variant	1/12	1	NM_170707.4	P1
LMNA	ENST00000677389.1	c.241T>C	p.Tyr81His	missense_variant	1/10		NM_005572.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Athena Diagnostics

Jan 14, 2020

Not found in the total gnomAD dataset, and the data is high quality. Predicted to have a damaging effect on the protein. One de novo case with parental identity confirmed. -

Charcot-Marie-Tooth disease type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 29, 2019

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has been reported in several individuals with a personal or family history of LMNA-related conditions (PMID: 27884249). In addition, this variant was observed in an individual with cardiomyopathy and skeletal muscle weakness (Invitae), the individual's parents reportedly did not not carry the p.Tyr81His variant suggesting that it arose de novo. This variant is not present in population databases (ExAC no frequency). This sequence change replaces tyrosine with histidine at codon 81 of the LMNA protein (p.Tyr81His). The tyrosine residue is highly conserved and there is a moderate physicochemical difference between tyrosine and histidine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
CardioboostCm	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
Cadd	Pathogenic	31
Dann	Uncertain	1.0
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.8	H;.;H;H;H
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-4.5	D;D;D;D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.96
MutPred		0.82		Loss of phosphorylation at Y81 (P = 0.0589);Loss of phosphorylation at Y81 (P = 0.0589);Loss of phosphorylation at Y81 (P = 0.0589);Loss of phosphorylation at Y81 (P = 0.0589);Loss of phosphorylation at Y81 (P = 0.0589);
MVP		0.96
MPC		2.4
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.91
gMVP		1.0

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: rs1553261977; hg19: chr1-156084950;