6-129288059-G-C

Position:

chr6-129288059-G-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000426.4(LAMA2):c.2749+1G>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,612,684 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

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

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

LAMA2
NM_000426.4 splice_donor

Scores

Splicing: ADA: 1.000

Clinical Significance

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

Conservation

PhyloP100: 10.0

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 18 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 6-129288059-G-C is Pathogenic according to our data. Variant chr6-129288059-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 194920.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr6-129288059-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LAMA2	NM_000426.4 linkuse as main transcript	c.2749+1G>C		splice_donor_variant		ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2 linkuse as main transcript	c.2749+1G>C		splice_donor_variant			NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	Effect	TSL	MANE	Protein	Appris
LAMA2	ENST00000421865.3 linkuse as main transcript	c.2749+1G>C	splice_donor_variant	5	NM_000426.4	ENSP00000400365
LAMA2	ENST00000617695.5 linkuse as main transcript	c.2749+1G>C	splice_donor_variant	5		ENSP00000481744
LAMA2	ENST00000618192.5 linkuse as main transcript	c.2749+1G>C	splice_donor_variant	5		ENSP00000480802	P1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152180

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:

0.00000205

AC:

AN:

1460504

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726674

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:

0.00000270

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74348

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

Alfa

AF:

0.0000312

Hom.:

Bravo

AF:

0.00000378

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

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Feb 24, 2022	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 194920). Disruption of this splice site has been observed in individuals with clinical features of congenital muscular dystrophy (PMID: 21922472, 24225367). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 19 of the LAMA2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in LAMA2 are known to be pathogenic (PMID: 18700894, 32904964). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 22, 2024	Variant summary: LAMA2 c.2749+1G>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 1612800 control chromosomes. c.2749+1G>C has been reported in the literature in the homozygous state in an individual affected with Laminin Alpha 2-Related Dystrophy (Chakravorty_2020). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 33250842). ClinVar contains an entry for this variant (Variation ID: 194920). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 30, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Apr 17, 2015	- -

Merosin deficient congenital muscular dystrophy

Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Counsyl

Nov 21, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

1.3

Eigen_PC

Pathogenic

1.1

FATHMM_MKL

Pathogenic

0.99

MutationTaster

Benign

1.0

GERP RS

5.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_DL_spliceai

1.0

Position offset: -1

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