rs1057518706

Positions:

• chr3-48572667-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP5_Moderate

The NM_000094.4(COL7A1):​c.6900+4A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000689 in 1,452,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: COL7A1 NM_000094.4 splice_region, intron
• Scores: Splicing: ADA: 0.9788
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 1.46

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-48572667-T-C is Pathogenic according to our data. Variant chr3-48572667-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 374314.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr3-48572667-T-C is described in Lovd as [Likely_pathogenic]. Variant chr3-48572667-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL7A1	NM_000094.4	c.6900+4A>G		splice_region_variant, intron_variant		ENST00000681320.1	NP_000085.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL7A1	ENST00000681320.1	c.6900+4A>G		splice_region_variant, intron_variant			NM_000094.4	ENSP00000506558.1
COL7A1	ENST00000328333.12	c.6900+4A>G		splice_region_variant, intron_variant		1		ENSP00000332371.8
COL7A1	ENST00000487017.5	n.2817+4A>G		splice_region_variant, intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.89e-7 AC: 1 AN: 1452080 Hom.: 0 Cov.: 37 AF XY: 0.00 AC XY: 0 AN XY: 721560

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.03e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 09, 2020

Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Experimental studies have shown that this variant disrupts mRNA splicing (PMID: 16965329). 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. This variant has been observed in individual(s) with dystrophic epidermolysis bullosa (PMID: 10504458, 16965329, 17425959). ClinVar contains an entry for this variant (Variation ID: 374314). This sequence change falls in intron 87 of the COL7A1 gene. It does not directly change the encoded amino acid sequence of the COL7A1 protein, but it affects a nucleotide within the consensus splice site of the intron. This variant is not present in population databases (ExAC no frequency). -

Generalized dominant dystrophic epidermolysis bullosa Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Baylor Genetics

May 01, 2016

Our laboratory has reported dual molecular diagnoses in COL7A1 (NM_000094.3:c.6900+4A>G) and DDX3X (NM_001356.3:c.1052G>A) in an individual with microcephaly, delayed motor milestones, delayed speech, hypotonia, hyperreflexia, repetitive behaviors, dysmorphic features, mild conductive hearing loss, mild epidermolysis bullosa (EB) and a history of prematurity and genital anomalies. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.55
CADD	Benign	21
DANN	Benign	0.80

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.98
dbscSNV1_RF	Pathogenic	0.85
SpliceAI score (max)		0.58		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.58		Position offset: 4

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

Publications

LitVar

Other links and lift over

dbSNP: rs1057518706; hg19: chr3-48610100;