rs374815503

chr6-129454272-C-Achr6-129454272-C-Gchr6-129454272-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000426.4(LAMA2):c.6691C>A(p.Arg2231Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. R2231H) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LAMA2 NM_000426.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.39

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]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.836

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LAMA2	NM_000426.4	c.6691C>A	p.Arg2231Ser	missense_variant	47/65	ENST00000421865.3
LAMA2	NM_001079823.2	c.6691C>A	p.Arg2231Ser	missense_variant	47/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LAMA2	ENST00000421865.3	c.6691C>A	p.Arg2231Ser	missense_variant	47/65	5	NM_000426.4
	ENST00000665046.1	n.976-13020G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital muscular dystrophy due to partial LAMA2 deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
Cadd	Pathogenic	29
Dann	Uncertain	1.0
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Benign	0.80	T;T;T
M_CAP	Benign	0.023	T
MetaRNN	Pathogenic	0.84	D;D;D
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.58	T
Polyphen		1.0	.;.;D
Vest4		0.94
MutPred		0.58		.;Loss of MoRF binding (P = 0.0235);Loss of MoRF binding (P = 0.0235);
MVP		0.70
MPC		0.50
ClinPred		0.98	D
GERP RS		5.8
Varity_R		0.48
gMVP		0.76

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.34		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.34		Position offset: -5

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs374815503; hg19: chr6-129775417; COSMIC: COSV101370579;