1-156115012-A-T

Variant names:

• chr1-156115012-A-T
• rs1553261891
• NM_170707.4:c.94A>T

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.94A>T​(p.Lys32*) variant causes a stop gained 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. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. K32K) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LMNA NM_170707.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.32

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 does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 773 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-156115012-A-T is Pathogenic according to our data. Variant chr1-156115012-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 655996.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.94A>T	p.Lys32*	stop_gained	Exon 1 of 12	ENST00000368300.9	NP_733821.1
LMNA	NM_005572.4	c.94A>T	p.Lys32*	stop_gained	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.94A>T	p.Lys32*	stop_gained	Exon 1 of 12	1	NM_170707.4	ENSP00000357283.4
LMNA	ENST00000677389.1	c.94A>T	p.Lys32*	stop_gained	Exon 1 of 10		NM_005572.4	ENSP00000503633.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Apr 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys32*) 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 (ExAC no frequency). This variant has not been reported in the literature in individuals with LMNA-related conditions. ClinVar contains an entry for this variant (Variation ID: 655996). For these reasons, this variant has been classified as Pathogenic. -

Dilated cardiomyopathy 1A Pathogenic:1

Mar 31, 2022

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0103 - Dominant negative, loss of function and gain of function are known mechanisms of disease in this gene. Some missense variants have been reported to result in a toxic gain of function or dominant negative and are associated with childhood-onset disease or skeletal muscle involvement, while other variants have been reported to result in a loss of function and haploinsufficiency, and are associated with adult-onset disease, cardiac disorders or myopathy (PMID: 17377071). (I) 0108 - This gene is associated with both recessive and dominant disease (OMIM). (I) 0204 - Variant is predicted to result in a truncated protein (premature termination codon is located within the first 102 nucleotides of the coding sequence and is predicted to escape nonsense-mediated decay) with at least 1/3 of the protein sequence affected. (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0702 - Other variants predicted to escape NMD, comparable to the one identified in this case have strong previous evidence for pathogenicity. These variants have been reported as pathogenic or likely pathogenic, and observed in heterozygous individuals with sudden death, dilated cardiomyopathy, Emery-Dreifuss muscular dystrophy and/or limb girdle muscular dystrophy (ClinVar, PMID: 31957533, PMID: 11138304, PMID: 24656463, PMID: 31762841). (SP) 0803 - This variant has limited previous evidence of pathogenicity in an unrelated individual. This variant has been reported as pathogenic (ClinVar). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	39
DANN	Uncertain	0.99
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.99	D
Vest4		0.90
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.9

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: rs1553261891; hg19: chr1-156084803;