NM_002291.3:c.1422C>G

Variant names:

• chr7-107975046-G-C
• rs780369106
• NM_002291.3:c.1422C>G

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6 BP7

The NM_002291.3(LAMB1):​c.1422C>G​(p.Ser474Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000496 in 1,613,196 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000049 (0 hom.)
• Consequence: LAMB1 NM_002291.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:3
• Conservation: PhyloP100: -3.17
• Publications: 1 publications found

Genes affected

LAMB1 (HGNC:6486): (laminin subunit beta 1) 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 are composed of 3 non identical chains: laminin alpha, beta and gamma (formerly A, B1, and B2, respectively) and they 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 1. The beta 1 chain has 7 structurally distinct domains which it shares with other beta chain isomers. The C-terminal helical region containing domains I and II are separated by domain alpha, domains III and V contain several EGF-like repeats, and domains IV and VI have a globular conformation. Laminin, beta 1 is expressed in most tissues that produce basement membranes, and is one of the 3 chains constituting laminin 1, the first laminin isolated from Engelbreth-Holm-Swarm (EHS) tumor. A sequence in the beta 1 chain that is involved in cell attachment, chemotaxis, and binding to the laminin receptor was identified and shown to have the capacity to inhibit metastasis. [provided by RefSeq, Aug 2011]

LAMB1 Gene-Disease associations (from GenCC):

• cobblestone lissencephaly without muscular or ocular involvement

  Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, PanelApp Australia, Genomics England PanelApp, G2P

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BP6: Variant 7-107975046-G-C is Benign according to our data. Variant chr7-107975046-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 211356.
• BP7: Synonymous conserved (PhyloP=-3.17 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002291.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMB1	NM_002291.3	MANE Select	c.1422C>G	p.Ser474Ser	synonymous	Exon 12 of 34	NP_002282.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMB1	ENST00000222399.11	TSL:1 MANE Select	c.1422C>G	p.Ser474Ser	synonymous	Exon 12 of 34	ENSP00000222399.6
	LAMB1	ENST00000393560.5	TSL:1	c.1422C>G	p.Ser474Ser	synonymous	Exon 12 of 19	ENSP00000377190.1
	LAMB1	ENST00000677793.1		c.1422C>G	p.Ser474Ser	synonymous	Exon 12 of 32	ENSP00000504020.1

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152150 Hom.: 0 Cov.: 32

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: 0.0000943

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000118

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000438 AC: 11 AN: 251018 AF XY: 0.0000368

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000968

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000486 AC: 71 AN: 1461046 Hom.: 0 Cov.: 29 AF XY: 0.0000509 AC XY: 37 AN XY: 726888

African (AFR) AF: 0.00 AC: 0 AN: 33454

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.0000383 AC: 1 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86238

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53258

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000621 AC: 69 AN: 1111412

Other (OTH) AF: 0.0000166 AC: 1 AN: 60368

GnomAD4 genome AF: 0.0000592 AC: 9 AN: 152150 Hom.: 0 Cov.: 32 AF XY: 0.0000673 AC XY: 5 AN XY: 74312

African (AFR) AF: 0.00 AC: 0 AN: 41432

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5200

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

European-Finnish (FIN) AF: 0.0000943 AC: 1 AN: 10602

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000118 AC: 8 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000676 Hom.: 0

Bravo AF: 0.0000416

EpiCase AF: 0.000164

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Benign:2

Oct 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jun 17, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not specified Uncertain:1

Apr 13, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

LAMB1-related disorder Benign:1

Jan 17, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	1.4
DANN	Benign	0.51
PhyloP100		-3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=99/1	polymorphism

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

Other links and lift over

dbSNP: rs780369106; hg19: chr7-107615491;