3-49124751-G-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2BP4

The NM_002292.4(LAMB2):c.3059C>A(p.Ala1020Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,844 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

LAMB2
NM_002292.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.16

Publications

0 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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.26900017).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB2	NM_002292.4 link	c.3059C>A	p.Ala1020Asp	missense_variant	Exon 21 of 32	ENST00000305544.9	NP_002283.3	P55268
LAMB2	XM_005265127.5 link	c.3059C>A	p.Ala1020Asp	missense_variant	Exon 22 of 33		XP_005265184.1	P55268

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMB2	ENST00000305544.9 link	c.3059C>A	p.Ala1020Asp	missense_variant	Exon 21 of 32	1	NM_002292.4	ENSP00000307156.4		P55268

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461844

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727218

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:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53378

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.450

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.:

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

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 18, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. This sequence change replaces alanine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 1020 of the LAMB2 protein (p.Ala1020Asp). 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: 567126). 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

Benign

0.11

BayesDel_addAF

Benign

-0.062

BayesDel_noAF

Benign

-0.33

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Benign

0.034

T;T

Eigen

Benign

-0.43

Eigen_PC

Benign

-0.20

FATHMM_MKL

Uncertain

0.91

LIST_S2

Benign

0.69

.;T

M_CAP

Benign

0.012

MetaRNN

Benign

0.27

T;T

MetaSVM

Benign

-0.97

MutationAssessor

Benign

-0.070

N;N

PhyloP100

2.2

PrimateAI

Benign

0.45

PROVEAN

Benign

0.18

N;N

REVEL

Benign

0.17

Sift

Benign

0.58

T;T

Sift4G

Benign

0.45

T;T

Polyphen

0.19

B;B

Vest4

0.48

MutPred

0.47

Gain of ubiquitination at K1023 (P = 0.0696);Gain of ubiquitination at K1023 (P = 0.0696);

MVP

0.39

MPC

0.38

ClinPred

0.71

GERP RS

4.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.069

gMVP

0.36

Mutation Taster

=83/17

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.070

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