chr9-131052965-G-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PP3_Strong

The NM_006059.4(LAMC3):c.1939G>T(p.Gly647Cys) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000156 in 1,607,172 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G647R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

LAMC3
NM_006059.4 missense, splice_region

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.66

Publications

1 publications found

Variant links:

Genes affected

LAMC3 (HGNC:6494): (laminin subunit gamma 3) 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 gamma chain isoform laminin, gamma 3. The gamma 3 chain is most similar to the gamma 1 chain, and contains all the 6 domains expected of the gamma chain. It is a component of laminin 12. The gamma 3 chain is broadly expressed in skin, heart, lung, and the reproductive tracts. In skin, it is seen within the basement membrane of the dermal-epidermal junction at points of nerve penetration. Gamma 3 is also a prominent element of the apical surface of ciliated epithelial cells of lung, oviduct, epididymis, ductus deferens, and seminiferous tubules. The distribution of gamma 3-containing laminins along ciliated epithelial surfaces suggests that the apical laminins are important in the morphogenesis and structural stability of the ciliated processes of these cells. [provided by RefSeq, Aug 2011]

LAMC3 Gene-Disease associations (from GenCC):

occipital pachygyria and polymicrogyria
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, Orphanet, Illumina
complex neurodevelopmental disorder
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

LAMC3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMC3	NM_006059.4 link	c.1939G>T	p.Gly647Cys	missense_variant, splice_region_variant	Exon 11 of 28	ENST00000361069.9	NP_006050.3	Q9Y6N6Q8N2D6
LAMC3	XM_011518121.2 link	c.1939G>T	p.Gly647Cys	missense_variant, splice_region_variant	Exon 11 of 28		XP_011516423.1
LAMC3	XM_006716921.3 link	c.1939G>T	p.Gly647Cys	missense_variant, splice_region_variant	Exon 11 of 23		XP_006716984.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMC3	ENST00000361069.9 link	c.1939G>T	p.Gly647Cys	missense_variant, splice_region_variant	Exon 11 of 28	2	NM_006059.4	ENSP00000354360.4		Q9Y6N6

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152262

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD2 exomes

AF:

0.00000817

AC:

AN:

244742

AF XY:

0.00

show subpopulations

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:

0.0000182

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000151

AC:

AN:

1454910

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

724222

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33328

American (AMR)

AF:

0.00

AC:

AN:

44660

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26070

East Asian (EAS)

AF:

0.00

AC:

AN:

39680

South Asian (SAS)

AF:

0.00

AC:

AN:

86048

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51792

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.0000172

AC:

AN:

1107390

Other (OTH)

AF:

0.0000499

AC:

AN:

60178

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.507

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152262

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74390

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41474

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68046

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.558

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Sep 21, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change affects codon 647 of the LAMC3 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the LAMC3 protein. This variant also falls at the last nucleotide of exon 11, which is part of the consensus splice site for this exon. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with LAMC3-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.27

BayesDel_addAF

Uncertain

0.098

BayesDel_noAF

Uncertain

0.010

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.17

Eigen

Uncertain

0.66

Eigen_PC

Uncertain

0.56

FATHMM_MKL

Uncertain

0.84

LIST_S2

Benign

0.44

M_CAP

Benign

0.035

MetaRNN

Uncertain

0.62

MetaSVM

Benign

-0.58

MutationAssessor

Pathogenic

3.1

PhyloP100

1.7

PrimateAI

Uncertain

0.51

PROVEAN

Pathogenic

-7.5

REVEL

Benign

0.29

Sift

Uncertain

0.0010

Sift4G

Uncertain

0.0050

Polyphen

1.0

Vest4

0.38

MutPred

0.62

Loss of glycosylation at S644 (P = 0.0709);

MVP

0.73

MPC

0.42

ClinPred

0.96

GERP RS

4.8

Varity_R

0.66

gMVP

0.69

Mutation Taster

=80/20

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.62

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.62

Position offset: 44

DS_DL_spliceai

0.48

Position offset: 0

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

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over