rs778012079

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_005562.3(LAMC2):c.2006_2012delTTTCAGA(p.Ile669LysfsTer14) variant causes a frameshift, splice region change. The variant allele was found at a frequency of 0.00000496 in 1,613,782 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

LAMC2
NM_005562.3 frameshift, splice_region

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 4.04

Publications

0 publications found

Variant links:

Genes affected

LAMC2 (HGNC:6493): (laminin subunit gamma 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), have 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 2. The gamma 2 chain, formerly thought to be a truncated version of beta chain (B2t), is highly homologous to the gamma 1 chain; however, it lacks domain VI, and domains V, IV and III are shorter. It is expressed in several fetal tissues but differently from gamma 1, and is specifically localized to epithelial cells in skin, lung and kidney. The gamma 2 chain together with alpha 3 and beta 3 chains constitute laminin 5 (earlier known as kalinin), which is an integral part of the anchoring filaments that connect epithelial cells to the underlying basement membrane. The epithelium-specific expression of the gamma 2 chain implied its role as an epithelium attachment molecule, and mutations in this gene have been associated with junctional epidermolysis bullosa, a skin disease characterized by blisters due to disruption of the epidermal-dermal junction. Two transcript variants resulting from alternative splicing of the 3' terminal exon, and encoding different isoforms of gamma 2 chain, have been described. The two variants are differentially expressed in embryonic tissues, however, the biological significance of the two forms is not known. Transcript variants utilizing alternative polyA_signal have also been noted in literature. [provided by RefSeq, Aug 2011]

LAMC2 Gene-Disease associations (from GenCC):

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

LAMC2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-183232330-CCAGATTT-C is Pathogenic according to our data. Variant chr1-183232330-CCAGATTT-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 371316.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMC2	NM_005562.3 link	c.2006_2012delTTTCAGA	p.Ile669LysfsTer14	frameshift_variant, splice_region_variant	Exon 13 of 23	ENST00000264144.5	NP_005553.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMC2	ENST00000264144.5 link	c.2006_2012delTTTCAGA	p.Ile669LysfsTer14	frameshift_variant, splice_region_variant	Exon 13 of 23	1	NM_005562.3	ENSP00000264144.4
LAMC2	ENST00000493293.5 link	c.2006_2012delTTTCAGA	p.Ile669LysfsTer14	frameshift_variant, splice_region_variant	Exon 13 of 22	1		ENSP00000432063.1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152040

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00219

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:

0.00000796

AC:

AN:

251332

AF XY:

0.00000736

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:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461742

Hom.:

AF XY:

0.00000138

AC XY:

AN XY:

727186

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5668

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111998

Other (OTH)

AF:

0.0000166

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152040

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41386

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10582

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68006

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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:

0.0000264

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Epidermolysis bullosa, junctional 3A, intermediate;C5676939:Epidermolysis bullosa, junctional 3B, severe

Pathogenic:1

May 07, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Nov 05, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Ile669Lysfs*14) in the LAMC2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in LAMC2 are known to be pathogenic (PMID: 11907499, 16473856). This variant is present in population databases (rs778012079, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with junctional epidermolysis bullosa (PMID: 16473856). This variant is also known as 2006del7. ClinVar contains an entry for this variant (Variation ID: 371316). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Junctional epidermolysis bullosa gravis of Herlitz

Pathogenic:1

Aug 26, 2016

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Junctional epidermolysis bullosa

Pathogenic:1

Mar 27, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: LAMC2 c.2006_2012delTTTCAGA (p.Ile669LysfsX14) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have not been observed at our laboratory but have been reported in the HGMD database. The variant allele was found at a frequency of 8e-06 in 251332 control chromosomes. c.2006_2012delTTTCAGA has been reported in the literature in at-least one homozygous individual affected with Herlitz Junctional Epidermolysis Bullosa (example, Varki_2006). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

4.0

Mutation Taster

=3/197

disease causing (ClinVar)

(source)

Splicing

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over