Genetic Variant LAMB1:p.Cys481Tyr (chr7-107975026-C-T) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_002291.3(LAMB1):c.1442G>A(p.Cys481Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C481F) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

LAMB1
NM_002291.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.57

Publications

2 publications found

Variant links:

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

LAMB1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr7-107975026-C-A is described in CliVar as Pathogenic. Clinvar id is 225688.Status of the report is no_assertion_criteria_provided, 0 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB1	NM_002291.3 link	c.1442G>A	p.Cys481Tyr	missense_variant	Exon 12 of 34	ENST00000222399.11	NP_002282.2	P07942Q8TAS6
LAMB1	XM_047420359.1 link	c.1442G>A	p.Cys481Tyr	missense_variant	Exon 12 of 28		XP_047276315.1
LAMB1	XM_047420360.1 link	c.1442G>A	p.Cys481Tyr	missense_variant	Exon 12 of 25		XP_047276316.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMB1	ENST00000222399.11 link	c.1442G>A	p.Cys481Tyr	missense_variant	Exon 12 of 34	1	NM_002291.3	ENSP00000222399.6		P07942

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

250870

AF XY:

0.00

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1460028

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726496

African (AFR)

AF:

0.00

AC:

AN:

33432

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86234

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53132

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1110588

Other (OTH)

AF:

0.00

AC:

AN:

60340

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.55

BayesDel_noAF

Pathogenic

0.55

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.33

.;T;T

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.91

FATHMM_MKL

Uncertain

0.91

LIST_S2

Pathogenic

0.99

D;D;D

M_CAP

Pathogenic

0.30

MetaRNN

Pathogenic

0.99

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

5.1

.;H;.

PhyloP100

7.6

PrimateAI

Uncertain

0.71

PROVEAN

Pathogenic

-11

D;D;D

REVEL

Pathogenic

0.87

Sift

Pathogenic

0.0

D;D;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;D;D

Vest4

0.95

MutPred

0.95

Loss of methylation at K506 (P = 0.0269);.;.;

MVP

0.99

MPC

0.62

ClinPred

1.0

GERP RS

5.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.96

gMVP

0.97

Mutation Taster

=4/96

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over