rs1055680335

chr3-48575497-G-Achr3-48575497-G-C

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000094.4(COL7A1):c.6022C>T(p.Arg2008Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,460,168 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R2008H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: COL7A1 NM_000094.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 2.60

Genes affected

COL7A1 (HGNC:2214): (collagen type VII alpha 1 chain) This gene encodes the alpha chain of type VII collagen. The type VII collagen fibril, composed of three identical alpha collagen chains, is restricted to the basement zone beneath stratified squamous epithelia. It functions as an anchoring fibril between the external epithelia and the underlying stroma. Mutations in this gene are associated with all forms of dystrophic epidermolysis bullosa. In the absence of mutations, however, an acquired form of this disease can result from an autoimmune response made to type VII collagen. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000094.4
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-48575496-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1324153.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, COL7A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• PP5: Variant 3-48575497-G-A is Pathogenic according to our data. Variant chr3-48575497-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 522791.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-48575497-G-A is described in Lovd as [Pathogenic]. Variant chr3-48575497-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL7A1	NM_000094.4	c.6022C>T	p.Arg2008Cys	missense_variant	74/119	ENST00000681320.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL7A1	ENST00000681320.1	c.6022C>T	p.Arg2008Cys	missense_variant	74/119		NM_000094.4	P1
COL7A1	ENST00000328333.12	c.6022C>T	p.Arg2008Cys	missense_variant	73/118	1		P1
COL7A1	ENST00000487017.5	n.1939C>T		non_coding_transcript_exon_variant	39/83	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000409 AC: 1 AN: 244660 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 133598

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000916

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460168 Hom.: 0 Cov.: 39 AF XY: 0.00000551 AC XY: 4 AN XY: 726392

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Recessive dystrophic epidermolysis bullosa Pathogenic:5

Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein	Jun 06, 2022	ACMG classification criteria: PS4 supporting, PM2 moderated, PM3 strong -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Research in Genodermatoses and Epidermolysis Bullosa, University of Buenos Aires	Mar 14, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory of Medical Genetics, National & Kapodistrian University of Athens	Nov 09, 2018	PM1, PM2, PM5, PP2, PP3, PP5 -
Likely pathogenic, no assertion criteria provided	clinical testing	Narges Medical Genetic and Prenatal Diagnosis Lab	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The missense variant p.R2008C in COL7A1 (NM_000094.4) has been reported previously in affected indviduals (Escámez MJ et al,2018). It has been submitted to ClinVar as Pathogenic. Other variants affecting this residue have been reported previously. The p.R2008C variant is observed in 1/1,09,206 (0.0009%) alleles from individuals of European (Non-Finnish) background in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes.The p.R2008C missense variant is predicted to be damaging by both SIFT and PolyPhen2. The nucleotide c.6022 in COL7A1 is predicted conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Pathogenic. -

Epidermolysis bullosa dystrophica Pathogenic:3

Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Apr 28, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Research Center, Shahid Beheshti University of Medical Sciences	Dec 03, 2017	- -
Pathogenic, criteria provided, single submitter	research	Biomedical Innovation Departament, CIEMAT	Mar 08, 2011	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Sep 11, 2023	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 10504458, 16271705, 15816848, 10367730, 27498345, 9740253, 34426522, 20184583, 31001817, 15888141, 10084325, 34008892, 35979658, 36578049, 36287101) -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jul 09, 2023	For these reasons, this variant has been classified as Pathogenic. This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 2008 of the COL7A1 protein (p.Arg2008Cys). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with dystrophic epidermolysis bullosa (PMID: 9740253, 10084325, 15888141, 16271705, 20184583). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 522791). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on COL7A1 protein function. This variant disrupts the p.Arg2008 amino acid residue in COL7A1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9326325, 10084325, 10504458). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
Cadd	Pathogenic	32
Dann	Uncertain	0.97
DEOGEN2	Uncertain	0.71	D
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Benign	0.69	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.35	D
MutationAssessor	Uncertain	2.3	M
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.38	T
PROVEAN	Uncertain	-3.3	D
REVEL	Uncertain	0.61
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.86		Loss of glycosylation at K2005 (P = 0.0028);
MVP		0.90
MPC		0.34
ClinPred		0.90	D
GERP RS		3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.19
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1055680335; hg19: chr3-48612930;