3-49124700-C-T

Position:

chr3-49124700-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong

The NM_002292.4(LAMB2):c.3109+1G>A variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000805 in 1,614,052 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

LAMB2
NM_002292.4 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Likely pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 5.96

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:

LAMB2 (HGNC:):

LAMB2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.04150454 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 3-49124700-C-T is Pathogenic according to our data. Variant chr3-49124700-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1068372.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LAMB2	NM_002292.4 linkuse as main transcript	c.3109+1G>A		splice_donor_variant, intron_variant		ENST00000305544.9	NP_002283.3	P55268
LAMB2	XM_005265127.5 linkuse as main transcript	c.3109+1G>A		splice_donor_variant, intron_variant			XP_005265184.1	P55268

Ensembl

Gene	Transcript	HGVSc	Effect	#exon/exons	TSL	MANE	Protein	UniProt
LAMB2	ENST00000305544.9 linkuse as main transcript	c.3109+1G>A	splice_donor_variant, intron_variant		1	NM_002292.4	ENSP00000307156.4	P55268
LAMB2	ENST00000418109.5 linkuse as main transcript	c.3109+1G>A	splice_donor_variant, intron_variant		1		ENSP00000388325.1	P55268
LAMB2	ENST00000462930.5 linkuse as main transcript	n.517G>A	non_coding_transcript_exon_variant	3/3	2
LAMB2	ENST00000542580.1 linkuse as main transcript	n.424+1G>A	splice_donor_variant, intron_variant		2

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152246

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251290

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135854

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000752

AC:

AN:

1461806

Hom.:

Cov.:

AF XY:

0.00000825

AC XY:

AN XY:

727206

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000719

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152246

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74382

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 09, 2022

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 1068372). This variant has not been reported in the literature in individuals affected with LAMB2-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change affects a donor splice site in intron 21 of the LAMB2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in LAMB2 are known to be pathogenic (PMID: 15367484). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Pierson syndrome

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Neuberg Centre For Genomic Medicine, NCGM

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.42

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Pathogenic

0.98

GERP RS

5.5

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.30

Position offset: -3

DS_DL_spliceai

0.99

Position offset: 1

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