rs864321654

Positions:

• chr3-48580633-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000094.4(COL7A1):​c.5000G>A​(p.Gly1667Glu) 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G1667G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL7A1 NM_000094.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.72

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_000094.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), COL7A1. . Gene score misZ 1.5899 (greater than the threshold 3.09). Trascript score misZ 4.0428 (greater than threshold 3.09). GenCC has associacion of gene with recessive dystrophic epidermolysis bullosa, dystrophic epidermolysis bullosa pruriginosa, recessive dystrophic epidermolysis bullosa-generalized other, transient bullous dermolysis of the newborn, epidermolysis bullosa with congenital localized absence of skin and deformity of nails, generalized dominant dystrophic epidermolysis bullosa, dystrophic epidermolysis bullosa, nails only, acral dystrophic epidermolysis bullosa, recessive dystrophic epidermolysis bullosa inversa, pretibial dystrophic epidermolysis bullosa.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL7A1	NM_000094.4	c.5000G>A	p.Gly1667Glu	missense_variant	55/119	ENST00000681320.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL7A1	ENST00000681320.1	c.5000G>A	p.Gly1667Glu	missense_variant	55/119		NM_000094.4	P1
COL7A1	ENST00000328333.12	c.5000G>A	p.Gly1667Glu	missense_variant	54/118	1		P1
COL7A1	ENST00000487017.5	n.917G>A		non_coding_transcript_exon_variant	20/83	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Recessive dystrophic epidermolysis bullosa Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Strand Center for Genomics and Personalized Medicine, Strand Life Sciences Pvt Ltd

-

The identified novel heterozygous missense substitution (p.Gly1667Glu) alters a conserved residue in the protein. The identified variant lies in the triple helical domain of the protein (1254-2784 aa). Another missense variant, p.Pro1699Leu which lies in the vicinity of the identified variant, and also lies in the triple helical domain, has been reported as 'pathogenic' in the ClinVar database (SCV000034653) with respect to epidermolysis bullosa, pretibial, autosomal recessive. Additionally, variations that typically involve glycine substitutions within the type VII collagen triple helix have been associated with a spectrum of dystrophic epidermolysis bullosa phenotypes [PMID:8644729]. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	30
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.80	D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.9	H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.80	D
PROVEAN	Pathogenic	-4.8	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.94		Loss of glycosylation at K1672 (P = 0.0123);
MVP		0.99
MPC		0.32
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.75
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.19		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: rs864321654; hg19: chr3-48618066;