1-209615252-C-T

Variant names:

• chr1-209615252-C-T
• rs369211699
• NM_000228.3:c.*19G>A

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_000228.3(LAMB3):​c.*19G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000174 in 1,613,916 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00063 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00013 (1 hom.)
• Consequence: LAMB3 NM_000228.3 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.11
• Publications: 0 publications found

Genes affected

LAMB3 (HGNC:6490): (laminin subunit beta 3) The product encoded by this gene is a laminin that belongs to a family of basement membrane proteins. This protein is a beta subunit laminin, which together with an alpha and a gamma subunit, forms laminin-5. Mutations in this gene cause epidermolysis bullosa junctional Herlitz type, and generalized atrophic benign epidermolysis bullosa, diseases that are characterized by blistering of the skin. Multiple alternatively spliced transcript variants that encode the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

LAMB3 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: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, Laboratory for Molecular Medicine
• junctional epidermolysis bullosa, non-Herlitz type

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Genomics England PanelApp, Ambry Genetics
• amelogenesis imperfecta type 1A

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• amelogenesis imperfecta type 1

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• generalized junctional epidermolysis bullosa non-Herlitz type

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.91).
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00063 (96/152322) while in subpopulation AFR AF = 0.00207 (86/41574). AF 95% confidence interval is 0.00172. There are 0 homozygotes in GnomAd4. There are 43 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB3	NM_000228.3	c.*19G>A		3_prime_UTR_variant	Exon 23 of 23	ENST00000356082.9	NP_000219.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMB3	ENST00000356082.9	c.*19G>A		3_prime_UTR_variant	Exon 23 of 23	1	NM_000228.3	ENSP00000348384.3
LAMB3	ENST00000367030.7	c.*19G>A		3_prime_UTR_variant	Exon 23 of 23	1		ENSP00000355997.3
LAMB3	ENST00000391911.5	c.*19G>A		3_prime_UTR_variant	Exon 22 of 22	1		ENSP00000375778.1

Frequencies

GnomAD3 genomes AF: 0.000631 AC: 96 AN: 152204 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00207

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000770

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00949

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000263 AC: 66 AN: 251104 AF XY: 0.000280

Gnomad AFR exome AF: 0.00185

Gnomad AMR exome AF: 0.000202

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00109

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000528

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000127 AC: 185 AN: 1461594 Hom.: 1 Cov.: 30 AF XY: 0.000133 AC XY: 97 AN XY: 727092

African (AFR) AF: 0.00245 AC: 82 AN: 33478

American (AMR) AF: 0.000157 AC: 7 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.000781 AC: 31 AN: 39698

South Asian (SAS) AF: 0.0000464 AC: 4 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53170

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5766

European-Non Finnish (NFE) AF: 0.0000378 AC: 42 AN: 1111978

Other (OTH) AF: 0.000298 AC: 18 AN: 60392

GnomAD4 genome AF: 0.000630 AC: 96 AN: 152322 Hom.: 0 Cov.: 33 AF XY: 0.000577 AC XY: 43 AN XY: 74492

African (AFR) AF: 0.00207 AC: 86 AN: 41574

American (AMR) AF: 0.00 AC: 0 AN: 15296

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.000771 AC: 4 AN: 5186

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.0102 AC: 3 AN: 294

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2112

Alfa AF: 0.000346 Hom.: 0

Bravo AF: 0.000699

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jul 17, 2020

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: LAMB3 c.*19G>A is located in the untranslated mRNA region downstream of the termination codon. The variant allele was found at a frequency of 0.00031 in 282504 control chromosomes, predominantly at a frequency of 0.002 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately equal to the estimated maximal expected allele frequency for a pathogenic variant in Junctional Epidermolysis Bullosa phenotype (0.002), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.*19G>A in individuals affected with Junctional Epidermolysis Bullosa and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.91
CADD	Benign	4.7
DANN	Benign	0.61
PhyloP100		-1.1
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs369211699; hg19: chr1-209788597; COSMIC: COSV99152026; COSMIC: COSV99152026;