rs72656357

Positions:

• chr7-94401622-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_000089.4(COL1A2):​c.279+2T>C variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: COL1A2 NM_000089.4 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 5.61

Genes affected

COL1A2 (HGNC:2198): (collagen type I alpha 2 chain) This gene encodes the pro-alpha2 chain of type I collagen whose triple helix comprises two alpha1 chains and one alpha2 chain. Type I is a fibril-forming collagen found in most connective tissues and is abundant in bone, cornea, dermis and tendon. Mutations in this gene are associated with osteogenesis imperfecta types I-IV, Ehlers-Danlos syndrome type VIIB, recessive Ehlers-Danlos syndrome Classical type, idiopathic osteoporosis, and atypical Marfan syndrome. Symptoms associated with mutations in this gene, however, tend to be less severe than mutations in the gene for the alpha1 chain of type I collagen (COL1A1) reflecting the different role of alpha2 chains in matrix integrity. Three transcripts, resulting from the use of alternate polyadenylation signals, have been identified for this gene. [provided by R. Dalgleish, Feb 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.012923677 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-94401622-T-C is Pathogenic according to our data. Variant chr7-94401622-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 17233.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL1A2	NM_000089.4	c.279+2T>C		splice_donor_variant, intron_variant		ENST00000297268.11	NP_000080.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL1A2	ENST00000297268.11	c.279+2T>C		splice_donor_variant, intron_variant		1	NM_000089.4	ENSP00000297268.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1435990 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 714866

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Ehlers-danlos syndrome, arthrochalasia type, 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jan 01, 1994

- -

Osteogenesis imperfecta type I;C0268335:Ehlers-Danlos syndrome, classic type, 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 13, 2017

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this splicing change leads to skipping of exon 6, which includes part of the triple-helical domain (PMID: 8081389, 2454224). This variant has been reported in several individuals affected with Ehlers-Danlos syndrome VII (PMID: 8081389, 23158907, 2454224). This variant is also known as IVS6+2T>C in the literature. ClinVar contains an entry for this variant (Variation ID: 17233). This variant is not present in population databases (rs72656357, ExAC no frequency). This sequence change affects a donor splice site in intron 6 of the COL1A2 gene. It is expected to disrupt RNA splicing and results in a disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.18
CADD	Pathogenic	27
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Uncertain	0.91	D
GERP RS		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.94		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs72656357; hg19: chr7-94030934;