Genetic Variant LAMA3:p.Gly2834Arg (chr18-23931125-G-C) – ACMG Classification: Uncertain_significance (0 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_198129.4(LAMA3):c.8500G>C(p.Gly2834Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,728 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 7/9 in silico tools predict a benign 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. G2834S) has been classified as Benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

LAMA3
NM_198129.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.824

Publications

30 publications found

Variant links:

Genes affected

LAMA3 (HGNC:6483): (laminin subunit alpha 3) The protein encoded by this gene belongs to the laminin family of secreted molecules. Laminins are heterotrimeric molecules that consist of alpha, beta, and gamma subunits that assemble through a coiled-coil domain. Laminins are essential for formation and function of the basement membrane and have additional functions in regulating cell migration and mechanical signal transduction. This gene encodes an alpha subunit and is responsive to several epithelial-mesenchymal regulators including keratinocyte growth factor, epidermal growth factor and insulin-like growth factor. Mutations in this gene have been identified as the cause of Herlitz type junctional epidermolysis bullosa and laryngoonychocutaneous syndrome. Alternative splicing and alternative promoter usage result in multiple transcript variants. [provided by RefSeq, Dec 2014]

LAMA3 Gene-Disease associations (from GenCC):

junctional epidermolysis bullosa
Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
laryngo-onycho-cutaneous syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet
junctional epidermolysis bullosa Herlitz type
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
junctional epidermolysis bullosa, non-Herlitz type
Inheritance: AR Classification: STRONG Submitted by: PanelApp Australia, Genomics England PanelApp
generalized junctional epidermolysis bullosa non-Herlitz type
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

LAMA3 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.10281351).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA3	NM_198129.4 link	c.8500G>C	p.Gly2834Arg	missense_variant	Exon 65 of 75	ENST00000313654.14	NP_937762.2	Q16787-2
LAMA3	NM_000227.6 link	c.3673G>C	p.Gly1225Arg	missense_variant	Exon 28 of 38	ENST00000269217.11	NP_000218.3	Q16787-1A0A0A6YYF2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA3	ENST00000313654.14 link	c.8500G>C	p.Gly2834Arg	missense_variant	Exon 65 of 75	1	NM_198129.4	ENSP00000324532.8		Q16787-2
LAMA3	ENST00000269217.11 link	c.3673G>C	p.Gly1225Arg	missense_variant	Exon 28 of 38	1	NM_000227.6	ENSP00000269217.5		Q16787-1A0A0A6YYF2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460728

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726768

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86234

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110944

Other (OTH)

AF:

0.00

AC:

AN:

60370

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.096

BayesDel_noAF

Benign

-0.97

CADD

Benign

0.0090

(source)

DEOGEN2

Benign

0.011

.;T;.;.;.;T

LIST_S2

Benign

0.68

.;T;T;T;T;T

MetaRNN

Benign

0.10

T;T;T;T;T;T

PhyloP100

-0.82

Sift4G

Benign

0.14

.;.;.;T;T;T

Vest4

0.038

gMVP

0.51

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