GeneBe

rs143974640

Positions:

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_002292.4(LAMB2):​c.4222C>T​(p.Leu1408=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00112 in 1,611,696 control chromosomes in the GnomAD database, including 21 homozygotes. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0062 ( 12 hom., cov: 33)
Exomes 𝑓: 0.00059 ( 9 hom. )

Consequence

LAMB2
NM_002292.4 splice_region, synonymous

Scores

2
Splicing: ADA: 0.0008201
2

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: 1.71
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -20 ACMG points.

BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.57).
BP6
Variant 3-49123134-G-A is Benign according to our data. Variant chr3-49123134-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 345979.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
BS1
Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00619 (942/152240) while in subpopulation AFR AF= 0.0216 (899/41548). AF 95% confidence interval is 0.0205. There are 12 homozygotes in gnomad4. There are 448 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
BS2
High Homozygotes in GnomAd4 at 12 AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
LAMB2NM_002292.4 linkuse as main transcriptc.4222C>T p.Leu1408= splice_region_variant, synonymous_variant 26/32 ENST00000305544.9 NP_002283.3
LAMB2XM_005265127.5 linkuse as main transcriptc.4222C>T p.Leu1408= splice_region_variant, synonymous_variant 27/33 XP_005265184.1

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
LAMB2ENST00000305544.9 linkuse as main transcriptc.4222C>T p.Leu1408= splice_region_variant, synonymous_variant 26/321 NM_002292.4 ENSP00000307156 P1
LAMB2ENST00000418109.5 linkuse as main transcriptc.4222C>T p.Leu1408= splice_region_variant, synonymous_variant 27/331 ENSP00000388325 P1
LAMB2ENST00000469665.1 linkuse as main transcriptn.452C>T non_coding_transcript_exon_variant 3/32

Frequencies

GnomAD3 genomes
AF:
0.00614
AC:
934
AN:
152122
Hom.:
12
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0215
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00196
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00316
Gnomad NFE
AF:
0.0000294
Gnomad OTH
AF:
0.00478
GnomAD3 exomes
AF:
0.00160
AC:
400
AN:
249932
Hom.:
5
AF XY:
0.00131
AC XY:
177
AN XY:
135332
show subpopulations
Gnomad AFR exome
AF:
0.0210
Gnomad AMR exome
AF:
0.00119
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.000163
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000617
Gnomad OTH exome
AF:
0.000816
GnomAD4 exome
AF:
0.000593
AC:
865
AN:
1459456
Hom.:
9
Cov.:
34
AF XY:
0.000577
AC XY:
419
AN XY:
726208
show subpopulations
Gnomad4 AFR exome
AF:
0.0197
Gnomad4 AMR exome
AF:
0.00148
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.000139
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000252
Gnomad4 OTH exome
AF:
0.00142
GnomAD4 genome
AF:
0.00619
AC:
942
AN:
152240
Hom.:
12
Cov.:
33
AF XY:
0.00602
AC XY:
448
AN XY:
74446
show subpopulations
Gnomad4 AFR
AF:
0.0216
Gnomad4 AMR
AF:
0.00196
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:
0.00473
Alfa
AF:
0.00336
Hom.:
2
Bravo
AF:
0.00703
Asia WGS
AF:
0.00115
AC:
4
AN:
3478

ClinVar

Significance: Benign/Likely benign
Submissions summary: Benign:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Benign:2
Likely benign, criteria provided, single submitternot providedBreakthrough Genomics, Breakthrough Genomics-- -
Likely benign, criteria provided, single submitterclinical testingGeneDxMar 02, 2020- -
Pierson syndrome;C3280113:LAMB2-related infantile-onset nephrotic syndrome Benign:1
Benign, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpJan 18, 2024- -
LAMB2-related infantile-onset nephrotic syndrome Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 13, 2018This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Pierson syndrome Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 13, 2018This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.57
CADD
Benign
15
DANN
Benign
0.54

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Benign
0.00082
dbscSNV1_RF
Benign
0.17
SpliceAI score (max)
0.56
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.56
Position offset: 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.

Other links and lift over

dbSNP: rs143974640; hg19: chr3-49160567; API