chr1-209623999-G-A
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_000228.3(LAMB3):c.1978C>T(p.Arg660*) variant causes a stop gained, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000242 in 1,612,492 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R660R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000228.3 stop_gained, splice_region
Scores
Clinical Significance
Conservation
Publications
- junctional epidermolysis bullosaInheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
- junctional epidermolysis bullosa Herlitz typeInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, Laboratory for Molecular Medicine
- junctional epidermolysis bullosa, non-Herlitz typeInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Genomics England PanelApp, Ambry Genetics
- amelogenesis imperfecta type 1AInheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
- amelogenesis imperfecta type 1Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- generalized junctional epidermolysis bullosa non-Herlitz typeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| LAMB3 | NM_000228.3 | c.1978C>T | p.Arg660* | stop_gained, splice_region_variant | Exon 15 of 23 | ENST00000356082.9 | NP_000219.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| LAMB3 | ENST00000356082.9 | c.1978C>T | p.Arg660* | stop_gained, splice_region_variant | Exon 15 of 23 | 1 | NM_000228.3 | ENSP00000348384.3 | ||
| LAMB3 | ENST00000367030.7 | c.1978C>T | p.Arg660* | stop_gained, splice_region_variant | Exon 15 of 23 | 1 | ENSP00000355997.3 | |||
| LAMB3 | ENST00000391911.5 | c.1978C>T | p.Arg660* | stop_gained, splice_region_variant | Exon 14 of 22 | 1 | ENSP00000375778.1 |
Frequencies
GnomAD3 genomes AF: 0.0000591 AC: 9AN: 152168Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000200 AC: 5AN: 249798 AF XY: 0.0000148 show subpopulations
GnomAD4 exome AF: 0.0000205 AC: 30AN: 1460208Hom.: 0 Cov.: 33 AF XY: 0.0000234 AC XY: 17AN XY: 726524 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000591 AC: 9AN: 152284Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3AN XY: 74456 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Junctional epidermolysis bullosa gravis of Herlitz Pathogenic:2
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.
Variant summary: LAMB3 c.1978C>T (p.Arg660X) 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. The variant allele was found at a frequency of 2.2e-05 in 275670 control chromosomes (gnomAD). c.1978C>T has been reported in the literature in multiple individuals affected with Junctional Epidermolysis Bullosa (Christiano_1997, Yuen_2011, Varki_2006). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. A ClinVar submission from a clinical diagnostic laboratory (evaluation after 2014) cites the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.
not provided Pathogenic:2
Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 16473856, 12813757, 8824879, 21801158, 9160387)
This sequence change creates a premature translational stop signal (p.Arg660*) in the LAMB3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in LAMB3 are known to be pathogenic (PMID: 11023379, 16473856). This variant is present in population databases (rs146794392, gnomAD 0.02%). This premature translational stop signal has been observed in individuals with autosomal recessive junctional epidermolysis bullosa (PMID: 9160387, 21801158). ClinVar contains an entry for this variant (Variation ID: 189034). For these reasons, this variant has been classified as Pathogenic.
Junctional epidermolysis bullosa, non-Herlitz type Pathogenic:1
The variant is observed at an extremely low frequency in the gnomAD v4.1.0 dataset (total allele frequency: 0.002%). Predicted Consequence/Location: Stop-gained (nonsense): predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000189034 /PMID: 9160387 /3billion dataset). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline.
Junctional epidermolysis bullosa gravis of Herlitz;C0268374:Junctional epidermolysis bullosa, non-Herlitz type;C4011403:Amelogenesis imperfecta type 1A Pathogenic:1
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at