rs121912842

Positions:

• chr3-48575502-C-T

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000094.4(COL7A1):​c.6017G>A​(p.Gly2006Asp) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. G2006A) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL7A1 NM_000094.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 6.14

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 19 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, 4 uncertain in NM_000094.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-48575502-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 2203368.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant where missense usually causes diseases, COL7A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 3-48575502-C-T is Pathogenic according to our data. Variant chr3-48575502-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 17448.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL7A1	NM_000094.4	c.6017G>A	p.Gly2006Asp	missense_variant	74/119	ENST00000681320.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL7A1	ENST00000681320.1	c.6017G>A	p.Gly2006Asp	missense_variant	74/119		NM_000094.4	P1
COL7A1	ENST00000328333.12	c.6017G>A	p.Gly2006Asp	missense_variant	73/118	1		P1
COL7A1	ENST00000487017.5	n.1934G>A		non_coding_transcript_exon_variant	39/83	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 39

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Generalized dominant dystrophic epidermolysis bullosa Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Molecular Diagnostics Laboratory, M Health Fairview: University of Minnesota	Jan 13, 2021	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jul 24, 1998	- -

COL7A1-related disorder Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Feb 23, 2024

The COL7A1 c.6017G>A variant is predicted to result in the amino acid substitution p.Gly2006Asp. This variant was documented in a family with autosomal dominant epidermolysis bullosa (Hammami-Hauasli et al. 1998. PubMed ID: 9668111). This variant resides in exon 73 and results in a glycine residue substitution. Glycine substitution variants in the triple helical domain (Gly-X-Y; especially in exons 73, 74, and 75) are predominant in autosomal dominant dystrophic epidermolysis bullosa (DDEB; https://www.ncbi.nlm.nih.gov/books/NBK1304/). Functional studies support its pathogenicity (Fritsch et al. 2009. PubMed ID: 19726672). In addition, other missense changes at the same amino-acid position (p.Gly2006Ala and p.Gly2006Ser) have also been documented in individuals with autosomal dominant epidermolysis bullosa (Whittock et al. 1999. PubMed ID: 10504458; Mallipeddi et al. 2003. PubMed ID: 14616374). The c.6017G>A (p.Gly2006Asp) variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. In summary, this variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	30
DANN	Benign	0.97
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.41	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	4.4	H
MutationTaster	Benign	1.0	A;A
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.90		Loss of glycosylation at K2005 (P = 0.0028);
MVP		0.97
MPC		0.32
ClinPred		1.0	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.84
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs121912842; hg19: chr3-48612935;