3-48590258-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000094.4(COL7A1):c.2005C>G(p.Arg669Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,624 control chromosomes in the GnomAD database, with no homozygous occurrence. 15/24 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R669Q) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

COL7A1
NM_000094.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.888

Publications

0 publications found

Variant links:

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

COL7A1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL7A1	NM_000094.4 link	c.2005C>G	p.Arg669Gly	missense_variant	Exon 16 of 119	ENST00000681320.1	NP_000085.1	Q02388-1Q59F16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL7A1	ENST00000681320.1 link	c.2005C>G	p.Arg669Gly	missense_variant	Exon 16 of 119		NM_000094.4	ENSP00000506558.1		Q02388-1
COL7A1	ENST00000328333.12 link	c.2005C>G	p.Arg669Gly	missense_variant	Exon 15 of 118	1		ENSP00000332371.8		Q02388-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461624

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727118

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53250

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111960

Other (OTH)

AF:

0.00

AC:

AN:

60388

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Aug 09, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 669 of the COL7A1 protein (p.Arg669Gly). 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.089

BayesDel_noAF

Benign

-0.37

CADD

Benign

(source)

DANN

Benign

0.58

DEOGEN2

Benign

0.14

Eigen

Benign

-0.54

Eigen_PC

Benign

-0.60

FATHMM_MKL

Benign

0.13

LIST_S2

Benign

0.72

M_CAP

Benign

0.010

MetaRNN

Uncertain

0.51

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.8

PhyloP100

0.89

PrimateAI

Benign

0.48

PROVEAN

Benign

-0.58

REVEL

Benign

0.24

Sift

Benign

0.15

Sift4G

Uncertain

0.023

Polyphen

0.80

Vest4

0.64

MutPred

0.54

Loss of methylation at R669 (P = 0.0491);

MVP

0.70

MPC

0.32

ClinPred

0.38

GERP RS

2.7

Varity_R

0.16

gMVP

0.36

Mutation Taster

=38/62

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.31

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.31

Position offset: 19

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over