NM_000426.4:c.437C>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2PM5PP3_ModeratePP5

The NM_000426.4(LAMA2):c.437C>T(p.Ser146Phe) 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 1,461,526 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S146Y) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

LAMA2
NM_000426.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:3

Conservation

PhyloP100: 2.06

Publications

10 publications found

Variant links:

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)

LAMA2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr6-129098213-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1431679.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.88

PP5

Variant 6-129098213-C-T is Pathogenic according to our data. Variant chr6-129098213-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 162573.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA2	NM_000426.4 link	c.437C>T	p.Ser146Phe	missense_variant	Exon 4 of 65	ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2 link	c.437C>T	p.Ser146Phe	missense_variant	Exon 4 of 64		NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA2	ENST00000421865.3 link	c.437C>T	p.Ser146Phe	missense_variant	Exon 4 of 65	5	NM_000426.4	ENSP00000400365.2		P24043

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251462

AF XY:

0.00000736

show subpopulations

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

AF:

0.00000342

AC:

AN:

1461526

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727100

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1111680

Other (OTH)

AF:

0.00

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.515

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Merosin deficient congenital muscular dystrophy

Pathogenic:1Uncertain:1

Feb 13, 2023

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 23, 2018

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

not provided

Pathogenic:1Uncertain:1

Aug 30, 2019

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Observed in an individual with congenital muscular dystrophy who harbored a second variant on the opposite LAMA2 allele (Oliveira et al., 2018); Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 26633542, 30055037) -

Mar 10, 2021

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

LAMA2-related muscular dystrophy

Uncertain:1

Aug 12, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces serine with phenylalanine at codon 146 of the LAMA2 protein (p.Ser146Phe). The serine residue is moderately conserved and there is a large physicochemical difference between serine and phenylalanine. This variant is present in population databases (rs143680577, ExAC 0.001%). This missense change has been observed in individual(s) with congenital muscular dystrophy type 1A (PMID: 30055037). ClinVar contains an entry for this variant (Variation ID: 162573). 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 v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.22

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.067

.;T;D

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

D;D;D

M_CAP

Benign

0.073

MetaRNN

Pathogenic

0.88

D;D;D

MetaSVM

Uncertain

0.66

MutationAssessor

Pathogenic

3.9

.;.;H

PhyloP100

2.1

PrimateAI

Uncertain

0.77

PROVEAN

Pathogenic

-4.8

.;.;D

REVEL

Pathogenic

0.85

Sift

Uncertain

0.0010

.;.;D

Polyphen

1.0

.;.;D

Vest4

0.89

MutPred

0.71

Loss of disorder (P = 0.041);Loss of disorder (P = 0.041);Loss of disorder (P = 0.041);

MVP

0.93

MPC

0.50

ClinPred

1.0

GERP RS

5.0

Varity_R

0.94

gMVP

0.89

Mutation Taster

=22/78

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over