chr3-48581295-C-T

Variant names:

• chr3-48581295-C-T
• rs786205561
• NM_000094.4:c.4864G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_000094.4(COL7A1):​c.4864G>A​(p.Gly1622Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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. G1622R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL7A1 NM_000094.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.57
• Publications: 0 publications found

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]

COL7A1 Gene-Disease associations (from GenCC):

• epidermolysis bullosa with congenital localized absence of skin and deformity of nails

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• dystrophic epidermolysis bullosa pruriginosa

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Orphanet
• recessive dystrophic epidermolysis bullosa

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Genomics England PanelApp, Ambry Genetics, G2P, ClinGen
• generalized dominant dystrophic epidermolysis bullosa

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia, Orphanet
• pretibial dystrophic epidermolysis bullosa

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• transient bullous dermolysis of the newborn

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• acral dystrophic epidermolysis bullosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dystrophic epidermolysis bullosa, nails only

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• recessive dystrophic epidermolysis bullosa inversa

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• recessive dystrophic epidermolysis bullosa-generalized other

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-48581295-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 191175.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 3-48581295-C-T is Pathogenic according to our data. Variant chr3-48581295-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2851789.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000094.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL7A1	NM_000094.4	MANE Select	c.4864G>A	p.Gly1622Ser	missense	Exon 52 of 119	NP_000085.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL7A1	ENST00000681320.1	MANE Select	c.4864G>A	p.Gly1622Ser	missense	Exon 52 of 119	ENSP00000506558.1
	COL7A1	ENST00000328333.12	TSL:1	c.4864G>A	p.Gly1622Ser	missense	Exon 51 of 118	ENSP00000332371.8
	COL7A1	ENST00000487017.5	TSL:5	n.781G>A		non_coding_transcript_exon	Exon 17 of 83

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Apr 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1622 of the COL7A1 protein (p.Gly1622Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with COL7A1-related conditions. 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) performed at Invitae indicates that this missense variant is expected to disrupt COL7A1 protein function. This variant disrupts the triple helix domain of COL7A1. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236), and variants at these glycine residues in COL7A1 are more frequently observed in individuals with disease than in the general population (PMID: 22058051). However, the clinical significance of this observation remains uncertain since only a limited number of affected individuals have been described to date. This variant disrupts the p.Gly1622 amino acid residue in COL7A1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 35222512). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.7	H
PhyloP100		3.6
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.1	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0060	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.99		Loss of catalytic residue at P1618 (P = 0.0722)
MVP		0.96
MPC		0.25
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.47
gMVP		1.0
Mutation Taster		=0/100	disease causing

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: rs786205561; hg19: chr3-48618728;