3-49121990-C-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_002292.4(LAMB2):c.4877G>C(p.Arg1626Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,608 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign 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. R1626Q) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

LAMB2
NM_002292.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.722

Publications

5 publications found

Variant links:

Genes affected

LAMB2 (HGNC:6487): (laminin subunit beta 2) Laminins, a family of extracellular matrix glycoproteins, are the major noncollagenous constituent of basement membranes. They have been implicated in a wide variety of biological processes including cell adhesion, differentiation, migration, signaling, neurite outgrowth and metastasis. Laminins, composed of 3 non identical chains: laminin alpha, beta and gamma (formerly A, B1, and B2, respectively), form a cruciform structure consisting of 3 short arms, each formed by a different chain, and a long arm composed of all 3 chains. Each laminin chain is a multidomain protein encoded by a distinct gene. Several isoforms of each chain have been described. Different alpha, beta and gamma chain isomers combine to give rise to different heterotrimeric laminin isoforms which are designated by Arabic numerals in the order of their discovery, i.e. alpha1beta1gamma1 heterotrimer is laminin 1. The biological functions of the different chains and trimer molecules are largely unknown, but some of the chains have been shown to differ with respect to their tissue distribution, presumably reflecting diverse functions in vivo. This gene encodes the beta chain isoform laminin, beta 2. The beta 2 chain contains the 7 structural domains typical of beta chains of laminin, including the short alpha region. However, unlike beta 1 chain, beta 2 has a more restricted tissue distribution. It is enriched in the basement membrane of muscles at the neuromuscular junctions, kidney glomerulus and vascular smooth muscle. Transgenic mice in which the beta 2 chain gene was inactivated by homologous recombination, showed defects in the maturation of neuromuscular junctions and impairment of glomerular filtration. Alternative splicing involving a non consensus 5' splice site (gc) in the 5' UTR of this gene has been reported. It was suggested that inefficient splicing of this first intron, which does not change the protein sequence, results in a greater abundance of the unspliced form of the transcript than the spliced form. The full-length nature of the spliced transcript is not known. [provided by RefSeq, Aug 2011]

LAMB2 Gene-Disease associations (from GenCC):

Pierson syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, PanelApp Australia, Orphanet
LAMB2-related infantile-onset nephrotic syndrome
Inheritance: AR Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)

LAMB2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.18559673).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002292.4. 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
	LAMB2	NM_002292.4	MANE Select	c.4877G>C	p.Arg1626Pro	missense	Exon 29 of 32	NP_002283.3

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
LAMB2	ENST00000305544.9	TSL:1 MANE Select	c.4877G>C	p.Arg1626Pro	missense	Exon 29 of 32	ENSP00000307156.4
LAMB2	ENST00000418109.5	TSL:1	c.4877G>C	p.Arg1626Pro	missense	Exon 30 of 33	ENSP00000388325.1
LAMB2	ENST00000498377.1	TSL:2	n.532G>C		non_coding_transcript_exon	Exon 2 of 5

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461608

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727138

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53142

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Pierson syndrome;C3280113:LAMB2-related infantile-onset nephrotic syndrome

Uncertain:1

Mar 09, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 1626 of the LAMB2 protein (p.Arg1626Pro). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with LAMB2-related conditions. ClinVar contains an entry for this variant (Variation ID: 472490). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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

Uncertain

0.39

BayesDel_addAF

Benign

-0.16

BayesDel_noAF

Benign

-0.47

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.34

Eigen

Benign

-0.59

Eigen_PC

Benign

-0.64

FATHMM_MKL

Benign

0.13

LIST_S2

Benign

0.56

M_CAP

Benign

0.027

MetaRNN

Benign

0.19

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.5

PhyloP100

-0.72

PrimateAI

Benign

0.21

PROVEAN

Uncertain

-2.8

REVEL

Benign

0.098

Sift

Uncertain

0.026

Sift4G

Benign

0.14

Polyphen

0.64

Vest4

0.42

MutPred

0.34

Loss of MoRF binding (P = 2e-04)

MVP

0.27

MPC

0.31

ClinPred

0.62

GERP RS

-2.4

Varity_R

0.37

gMVP

0.65

Mutation Taster

=79/21

polymorphism

(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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over