NM_000426.4:c.2T>C

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_000426.4(LAMA2):c.2T>C(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000148 in 1,551,984 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 (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

LAMA2
NM_000426.4 start_lost

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 3.27

Variant links:

Genes affected

LAMA2 (HGNC:6482): (laminin subunit alpha 2) Laminin, an extracellular protein, is a major component of the basement membrane. It is thought to mediate the attachment, migration, and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components. It is composed of three subunits, alpha, beta, and gamma, which are bound to each other by disulfide bonds into a cross-shaped molecule. This gene encodes the alpha 2 chain, which constitutes one of the subunits of laminin 2 (merosin) and laminin 4 (s-merosin). Mutations in this gene have been identified as the cause of congenital merosin-deficient muscular dystrophy. Two transcript variants encoding different proteins have been found for this gene. [provided by RefSeq, Jul 2008]

LAMA2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 16 ACMG points.

PVS1

Start lost variant, next in-frame start position is after 8 pathogenic variants. Next in-frame start position is after 192 CDS bases. Genomic position: 129049997. Lost 0.020 part of the original CDS.

PP5

Variant 6-128883247-T-C is Pathogenic according to our data. Variant chr6-128883247-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 477459.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr6-128883247-T-C is described in Lovd as [Pathogenic]. Variant chr6-128883247-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA2	NM_000426.4 link	c.2T>C	p.Met1?	start_lost	Exon 1 of 65	ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2 link	c.2T>C	p.Met1?	start_lost	Exon 1 of 64		NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA2	ENST00000421865.3 link	c.2T>C	p.Met1?	start_lost	Exon 1 of 65	5	NM_000426.4	ENSP00000400365.2		P24043

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152156

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000157

AC:

AN:

1399828

Hom.:

Cov.:

AF XY:

0.0000203

AC XY:

AN XY:

690884

show subpopulations

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:

0.0000185

Gnomad4 OTH exome

AF:

0.0000344

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152156

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74326

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000189

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000240

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

LAMA2-related muscular dystrophy

Pathogenic:2

Jun 23, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects the initiator methionine of the LAMA2 mRNA. The next in-frame methionine is located at codon 65. This variant is not present in population databases (gnomAD no frequency). Disruption of the initiator codon has been observed in individual(s) with merosin-deficient muscular dystrophy (PMID: 2152033, 9674786). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 477459). For these reasons, this variant has been classified as Pathogenic. -

Jun 01, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: LAMA2 c.2T>C (p.Met1Thr) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon. Pathogenic variants are found upstream of the nearest alternative in-frame start codon (ClinVar). Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 153910 control chromosomes (gnomAD). c.2T>C has been reported in the literature in individuals affected with Laminin Alpha 2-Related Dystrophy (Pegoraro_1998, Hayashi_2001, Oliveira_2018), and some were reported as compound heterozygous with other likely pathogenic variants in trans. These data indicate that the variant is likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 11369186, 30055037, 9674786). Four submitters have provided clinical-significance assessments for this variant to ClinVar after 2014, and classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided

Pathogenic:2

Jul 01, 2018

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 14, 2022

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Merosin deficient congenital muscular dystrophy

Pathogenic:1

Feb 20, 2018

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Uncertain

0.11

CADD

Uncertain

DANN

Uncertain

0.97

DEOGEN2

Benign

0.015

.;T;T

Eigen

Uncertain

0.42

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Benign

0.68

LIST_S2

Uncertain

0.90

D;D;D

M_CAP

Pathogenic

0.65

MetaRNN

Pathogenic

0.87

D;D;D

MetaSVM

Benign

-1.0

PROVEAN

Benign

-1.1

.;.;N

REVEL

Uncertain

0.44

Sift

Pathogenic

0.0

.;.;D

Polyphen

0.93

.;.;P

Vest4

0.88

MVP

0.79

ClinPred

1.0

GERP RS

5.2

Varity_R

0.84

gMVP

0.59

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over