chr3-49123762-T-C

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_002292.4(LAMB2):c.3763A>G(p.Thr1255Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,286 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

LAMB2
NM_002292.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 0.890

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.05403164).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB2	NM_002292.4 link	c.3763A>G	p.Thr1255Ala	missense_variant	Exon 24 of 32	ENST00000305544.9	NP_002283.3	P55268
LAMB2	XM_005265127.5 link	c.3763A>G	p.Thr1255Ala	missense_variant	Exon 25 of 33		XP_005265184.1	P55268

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMB2	ENST00000305544.9 link	c.3763A>G	p.Thr1255Ala	missense_variant	Exon 24 of 32	1	NM_002292.4	ENSP00000307156.4		P55268

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461062

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726854

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74364

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:2

Jul 05, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 472480). This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 1255 of the LAMB2 protein (p.Thr1255Ala). 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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The alanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Jan 11, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases

Uncertain:1

Sep 19, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.3763A>G (p.T1255A) alteration is located in exon 24 (coding exon 24) of the LAMB2 gene. This alteration results from a A to G substitution at nucleotide position 3763, causing the threonine (T) at amino acid position 1255 to be replaced by an alanine (A). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.068

BayesDel_addAF

Benign

-0.31

BayesDel_noAF

Benign

-0.69

CADD

Benign

DANN

Benign

0.94

DEOGEN2

Benign

0.066

T;T

Eigen

Benign

-0.60

Eigen_PC

Benign

-0.50

FATHMM_MKL

Benign

0.40

LIST_S2

Benign

0.54

.;T

M_CAP

Benign

0.0030

MetaRNN

Benign

0.054

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.57

N;N

PrimateAI

Benign

0.33

PROVEAN

Benign

-0.50

N;N

REVEL

Benign

0.043

Sift

Benign

0.20

T;T

Sift4G

Benign

0.30

T;T

Polyphen

0.0010

B;B

Vest4

0.081

MutPred

0.32

Loss of disorder (P = 0.1789);Loss of disorder (P = 0.1789);

MVP

0.23

MPC

0.16

ClinPred

0.064

GERP RS

3.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.025

gMVP

0.42

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over