3-49131716-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2PP3_ModeratePP5

The NM_002292.4(LAMB2):c.467G>A(p.Arg156His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,054 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. R156C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

LAMB2
NM_002292.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 7.90

Publications

2 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 5 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.937

PP5

Variant 3-49131716-C-T is Pathogenic according to our data. Variant chr3-49131716-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 472487.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB2	NM_002292.4 link	c.467G>A	p.Arg156His	missense_variant	Exon 5 of 32	ENST00000305544.9	NP_002283.3
LAMB2	XM_005265127.5 link	c.467G>A	p.Arg156His	missense_variant	Exon 6 of 33		XP_005265184.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
LAMB2	ENST00000305544.9 link	c.467G>A	p.Arg156His	missense_variant	Exon 5 of 32	1	NM_002292.4	ENSP00000307156.4
LAMB2	ENST00000418109.5 link	c.467G>A	p.Arg156His	missense_variant	Exon 6 of 33	1		ENSP00000388325.1
LAMB2	ENST00000494831.1 link	c.20G>A	p.Arg7His	missense_variant	Exon 3 of 5	2		ENSP00000444751.1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152086

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1460968

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

726744

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

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:

0.0000232

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52512

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1112004

Other (OTH)

AF:

0.00

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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

AF:

0.00000658

AC:

AN:

152086

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74292

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41406

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68010

Other (OTH)

AF:

0.00

AC:

AN:

2090

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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Pierson syndrome

Pathogenic:2

May 11, 2024

Genetics laboratory, Department of Obstetrics & Gynae, Institute of Kidney Diseases & Research Centre Dr. H.L. Trivedi Institute Of Transplantation Sciences

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

May 10, 2024

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

A Homozygous missense variation in exon 5 of the LAMB2 gene that results in the amino acid substitution of Histidine for Arginine at codon 156 was detected. The observed variant c.467G>A (p.Arg156His) has not been reported in the 1000 genomes and gnomAD databases and has a minor allelic frequency of 0.0004% in TOPMed database. The in silico prediction of the variant are damaging by LRT, DANN, PROVEAN and SIFT. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as likely pathogenic. -

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

Uncertain:1

Sep 06, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 472487). This variant has not been reported in the literature in individuals affected with LAMB2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 156 of the LAMB2 protein (p.Arg156His). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.64

D;D;D

Eigen

Pathogenic

0.99

Eigen_PC

Pathogenic

0.88

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Pathogenic

0.99

.;D;D

M_CAP

Uncertain

0.16

MetaRNN

Pathogenic

0.94

D;D;D

MetaSVM

Pathogenic

0.96

MutationAssessor

Pathogenic

3.5

H;H;.

PhyloP100

7.9

PrimateAI

Uncertain

0.75

PROVEAN

Pathogenic

-4.7

D;D;D

REVEL

Pathogenic

0.94

Sift

Pathogenic

0.0

D;D;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;D;.

Vest4

0.96

MutPred

0.78

Gain of ubiquitination at K153 (P = 0.044);Gain of ubiquitination at K153 (P = 0.044);.;

MVP

0.94

MPC

1.5

ClinPred

1.0

GERP RS

4.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.6

Varity_R

0.93

gMVP

0.90

Mutation Taster

=48/52

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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