6-129328300-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000426.4(LAMA2):c.4199G>T(p.Arg1400Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,613,882 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1400P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: LAMA2 NM_000426.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.21

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.876

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LAMA2	NM_000426.4	c.4199G>T	p.Arg1400Leu	missense_variant	29/65	ENST00000421865.3
LAMA2	NM_001079823.2	c.4199G>T	p.Arg1400Leu	missense_variant	29/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LAMA2	ENST00000421865.3	c.4199G>T	p.Arg1400Leu	missense_variant	29/65	5	NM_000426.4
LAMA2	ENST00000618192.5	c.4463G>T	p.Arg1488Leu	missense_variant	30/66	5		P1
LAMA2	ENST00000617695.5	c.4199G>T	p.Arg1400Leu	missense_variant	29/64	5

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152078 Hom.: 0 Cov.: 32

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: 3 AN: 1461804 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727216

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: 0.00000658 AC: 1 AN: 152078 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74282

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: 0.00000378

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

Invitae

Nov 28, 2021

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 1400 of the LAMA2 protein (p.Arg1400Leu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with LAMA2-related conditions. 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) performed at Invitae indicates that this missense variant is not expected to disrupt 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	Uncertain	0.38
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
Cadd	Pathogenic	27
Dann	Uncertain	1.0
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.88	D;D;D
MetaSVM	Uncertain	0.26	D
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.52	T
Polyphen		1.0	.;.;D
Vest4		0.84
MutPred		0.62		Loss of phosphorylation at S1403 (P = 0.0594);Loss of phosphorylation at S1403 (P = 0.0594);Loss of phosphorylation at S1403 (P = 0.0594);
MVP		0.88
MPC		0.50
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.73
gMVP		0.80

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs760541670; hg19: chr6-129649445;