6-129190331-T-C

Variant names:

• chr6-129190331-T-C
• rs373100233
• NM_000426.4:c.1594T>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000426.4(LAMA2):​c.1594T>C​(p.Trp532Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,126 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: LAMA2 NM_000426.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.54
• Publications: 1 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: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

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.1594T>C	p.Trp532Arg	missense	Exon 11 of 65	NP_000417.3
	LAMA2	NM_001079823.2		c.1594T>C	p.Trp532Arg	missense	Exon 11 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.1594T>C	p.Trp532Arg	missense	Exon 11 of 65	ENSP00000400365.2
	LAMA2	ENST00000618192.5	TSL:5	c.1594T>C	p.Trp532Arg	missense	Exon 11 of 66	ENSP00000480802.2
	LAMA2	ENST00000617695.5	TSL:5	c.1594T>C	p.Trp532Arg	missense	Exon 11 of 64	ENSP00000481744.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461126 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 726872

African (AFR) AF: 0.00 AC: 0 AN: 33470

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26104

East Asian (EAS) AF: 0.00 AC: 0 AN: 39674

South Asian (SAS) AF: 0.00 AC: 0 AN: 86230

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53384

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111420

Other (OTH) AF: 0.00 AC: 0 AN: 60366

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

LAMA2-related muscular dystrophy Uncertain:1

Aug 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tryptophan with arginine at codon 532 of the LAMA2 protein (p.Trp532Arg). The tryptophan residue is weakly conserved and there is a moderate physicochemical difference between tryptophan and arginine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with LAMA2-related conditions. 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: "Possibly 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	0.61
BayesDel_addAF	Uncertain	0.062	T
BayesDel_noAF	Benign	-0.15
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.081	T
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Benign	0.68	T
M_CAP	Benign	0.024	T
MetaRNN	Uncertain	0.71	D
MetaSVM	Benign	-1.0	T
MutationAssessor	Uncertain	2.1	M
PhyloP100		2.5
PrimateAI	Uncertain	0.62	T
PROVEAN	Pathogenic	-9.7	D
REVEL	Benign	0.23
Sift	Pathogenic	0.0	D
Polyphen		0.99	D
Vest4		0.67
MutPred		0.69		Gain of disorder (P = 0.0133)
MVP		0.65
MPC		0.54
ClinPred		0.97	D
GERP RS		5.7
Varity_R		0.82
gMVP		0.86
Mutation Taster		=71/29	polymorphism

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: rs373100233; hg19: chr6-129511476;