rs1555731178

Positions:

• chr18-23901162-CA-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_198129.4(LAMA3):​c.6041del​(p.Gln2014ArgfsTer15) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Q2014Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LAMA3 NM_198129.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.22

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]

ACMG classification

Verdict is Pathogenic. Variant got 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 18-23901162-CA-C is Pathogenic according to our data. Variant chr18-23901162-CA-C is described in ClinVar as [Pathogenic]. Clinvar id is 549906.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LAMA3	NM_198129.4	c.6041del	p.Gln2014ArgfsTer15	frameshift_variant	48/75	ENST00000313654.14
LAMA3	NM_000227.6	c.1214del	p.Gln405ArgfsTer15	frameshift_variant	11/38	ENST00000269217.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LAMA3	ENST00000313654.14	c.6041del	p.Gln2014ArgfsTer15	frameshift_variant	48/75	1	NM_198129.4	P1
LAMA3	ENST00000269217.11	c.1214del	p.Gln405ArgfsTer15	frameshift_variant	11/38	1	NM_000227.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Junctional epidermolysis bullosa gravis of Herlitz Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Nov 21, 2017

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 22, 2023

This sequence change creates a premature translational stop signal (p.Gln405Argfs*15) in the LAMA3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in LAMA3 are known to be pathogenic (PMID: 10366601, 11810295, 12915477, 16473856, 17362460, 22434185, 23869449, 27827380, 28087116). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with autosomal recessive junctional epidermolysis bullosa (PMID: 27375110). ClinVar contains an entry for this variant (Variation ID: 549906). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

LitVar

Other links and lift over

dbSNP: rs1555731178; hg19: chr18-21481126;