rs745890735

Positions:

• chr6-129291623-G-A
• chr6-129291623-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000426.4(LAMA2):​c.2759G>A​(p.Cys920Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,398 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LAMA2 NM_000426.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.57

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LAMA2	NM_000426.4	c.2759G>A	p.Cys920Tyr	missense_variant	20/65	ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2	c.2759G>A	p.Cys920Tyr	missense_variant	20/64		NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LAMA2	ENST00000421865.3	c.2759G>A	p.Cys920Tyr	missense_variant	20/65	5	NM_000426.4	ENSP00000400365
LAMA2	ENST00000618192.5	c.2759G>A	p.Cys920Tyr	missense_variant	20/66	5		ENSP00000480802	P1
LAMA2	ENST00000617695.5	c.2759G>A	p.Cys920Tyr	missense_variant	20/64	5		ENSP00000481744

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251408 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135874

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461398 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727026

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

LAMA2-related muscular dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 06, 2023

This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 920 of the LAMA2 protein (p.Cys920Tyr). This variant is present in population databases (rs745890735, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with LAMA2-related conditions. ClinVar contains an entry for this variant (Variation ID: 572413). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on LAMA2 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Benign	0.090	.;T;T
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.89	D;D;D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	.;.;H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-10	.;.;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	.;.;D
Polyphen		1.0	.;.;D
Vest4		0.97
MutPred		1.0		Loss of disorder (P = 0.0652);Loss of disorder (P = 0.0652);Loss of disorder (P = 0.0652);
MVP		0.96
MPC		0.62
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.99
gMVP		0.94

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: rs745890735; hg19: chr6-129612768;