rs775278003

Positions:

chr6-129315463-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PP3_ModeratePP5

The NM_000426.4(LAMA2):c.3556-13T>A variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,500 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

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

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

LAMA2
NM_000426.4 splice_polypyrimidine_tract, intron

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 0.376

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 Uncertain_significance. Variant got 3 ACMG points.

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 6-129315463-T-A is Pathogenic according to our data. Variant chr6-129315463-T-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 555549.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Likely_pathogenic=1, Uncertain_significance=1}. Variant chr6-129315463-T-A is described in Lovd as [Pathogenic]. Variant chr6-129315463-T-A is described in Lovd as [Pathogenic]. Variant chr6-129315463-T-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LAMA2	NM_000426.4 linkuse as main transcript	c.3556-13T>A		splice_polypyrimidine_tract_variant, intron_variant		ENST00000421865.3
LAMA2	NM_001079823.2 linkuse as main transcript	c.3556-13T>A		splice_polypyrimidine_tract_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	Effect	TSL	MANE	Appris
LAMA2	ENST00000421865.3 linkuse as main transcript	c.3556-13T>A	splice_polypyrimidine_tract_variant, intron_variant	5	NM_000426.4
LAMA2	ENST00000617695.5 linkuse as main transcript	c.3556-13T>A	splice_polypyrimidine_tract_variant, intron_variant	5
LAMA2	ENST00000618192.5 linkuse as main transcript	c.3820-13T>A	splice_polypyrimidine_tract_variant, intron_variant	5		P1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152232

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:

0.000192

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251408

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135888

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000272

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000411

AC:

AN:

1461268

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727016

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000101

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152232

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74374

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000192

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Merosin deficient congenital muscular dystrophy

Pathogenic:1Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Jun 27, 2018	This variant was determined to be likely pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. This variant has been previously reported to affect splicing of LAMA2 [PMID 24611677] -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Dec 12, 2017	- -

LAMA2-related muscular dystrophy

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 11, 2024

This sequence change falls in intron 24 of the LAMA2 gene. It does not directly change the encoded amino acid sequence of the LAMA2 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. This variant is present in population databases (rs775278003, gnomAD 0.03%). This variant has been observed in individual(s) with congenital muscular dystrophy (PMID: 24611677). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 555549). Studies have shown that this variant results in activation of a cryptic splice site and introduces a premature termination codon (PMID: 24611677). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.81

CADD

Benign

DANN

Benign

0.78

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_AG_spliceai

1.0

Position offset: 2

DS_AL_spliceai

0.84

Position offset: 13

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