rs371548755

Variant names:

• chr6-129313003-G-A
• rs371548755
• NM_000426.4:c.3317G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000426.4(LAMA2):​c.3317G>A​(p.Cys1106Tyr) variant causes a missense change involving the alteration of a 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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: LAMA2 NM_000426.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.69
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• congenital merosin-deficient muscular dystrophy 1A

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, G2P
• LAMA2-related muscular dystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• muscular dystrophy, limb-girdle, autosomal recessive 23

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000426.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMA2	NM_000426.4	MANE Select	c.3317G>A	p.Cys1106Tyr	missense	Exon 23 of 65	NP_000417.3
	LAMA2	NM_001079823.2		c.3317G>A	p.Cys1106Tyr	missense	Exon 23 of 64	NP_001073291.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMA2	ENST00000421865.3	TSL:5 MANE Select	c.3317G>A	p.Cys1106Tyr	missense	Exon 23 of 65	ENSP00000400365.2
	LAMA2	ENST00000618192.5	TSL:5	c.3581G>A	p.Cys1194Tyr	missense	Exon 24 of 66	ENSP00000480802.2
	LAMA2	ENST00000617695.5	TSL:5	c.3317G>A	p.Cys1106Tyr	missense	Exon 23 of 64	ENSP00000481744.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251480 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.00000756

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Nov 06, 2017

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Nov 17, 2022

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

LAMA2-related muscular dystrophy Uncertain:1

Aug 31, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine with tyrosine at codon 1106 of the LAMA2 protein (p.Cys1106Tyr). The cysteine residue is highly conserved and there is a large physicochemical difference between cysteine and tyrosine. This variant is present in population databases (rs371548755, ExAC 0.001%). 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: 586116). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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 v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Benign	0.091	T
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.81	T
M_CAP	Benign	0.062	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Pathogenic	4.6	H
PhyloP100		8.7
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-10	D
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MVP		0.89
MPC		0.62
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.96
gMVP		0.98
Mutation Taster		=6/94	disease causing

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

Other links and lift over

dbSNP: rs371548755; hg19: chr6-129634148;