rs756535650

Positions:

chr3-49126159-G-A

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 2P and 8B. PM2BP4_ModerateBP6BP7BS1

The NM_002292.4(LAMB2):c.2152C>T(p.Leu718=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000107 in 1,611,902 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L718L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00011 ( 1 hom. )

Consequence

LAMB2
NM_002292.4 splice_region, synonymous

Scores

Splicing: ADA: 0.00004392

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:1

Conservation

PhyloP100: 1.12

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 -6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.46).

BP6

Variant 3-49126159-G-A is Benign according to our data. Variant chr3-49126159-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 258602.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=1}.

BP7

Synonymous conserved (PhyloP=1.12 with no splicing effect.

BS1

Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.000114 (166/1459686) while in subpopulation MID AF= 0.00486 (28/5766). AF 95% confidence interval is 0.00345. There are 1 homozygotes in gnomad4_exome. There are 93 alleles in male gnomad4_exome subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LAMB2	NM_002292.4 linkuse as main transcript	c.2152C>T	p.Leu718=	splice_region_variant, synonymous_variant	17/32	ENST00000305544.9
LAMB2	XM_005265127.5 linkuse as main transcript	c.2152C>T	p.Leu718=	splice_region_variant, synonymous_variant	18/33

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LAMB2	ENST00000305544.9 linkuse as main transcript	c.2152C>T	p.Leu718=	splice_region_variant, synonymous_variant	17/32	1	NM_002292.4	P1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000643

AC:

AN:

248942

Hom.:

AF XY:

0.0000891

AC XY:

AN XY:

134646

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000869

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000196

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000530

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000114

AC:

166

AN:

1459686

Hom.:

Cov.:

AF XY:

0.000128

AC XY:

AN XY:

726116

show subpopulations

Gnomad4 AFR exome

AF:

0.000209

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000243

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000827

Gnomad4 OTH exome

AF:

0.000248

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152216

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74362

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000724

Hom.:

Bravo

AF:

0.0000302

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000164

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 03, 2023

This sequence change affects codon 718 of the LAMB2 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the LAMB2 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs756535650, gnomAD 0.02%). This variant has been observed in individual(s) with LAMB2-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 258602). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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. -

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.46

CADD

Benign

8.1

DANN

Benign

0.69

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000044

dbscSNV1_RF

Benign

0.036

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