NM_000089.4:c.279+2T>C

Variant names:

• chr7-94401622-T-C
• rs72656357
• NM_000089.4:c.279+2T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 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
• Publications: 0 publications found

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]

COL1A2 Gene-Disease associations (from GenCC):

• Ehlers-Danlos syndrome, arthrochalasia type, 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Illumina, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• osteogenesis imperfecta

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• osteogenesis imperfecta type 1

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• osteogenesis imperfecta type 2

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P, ClinGen
• osteogenesis imperfecta type 3

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
• osteogenesis imperfecta type 4

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• Ehlers-Danlos syndrome, arthrochalasia type

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
• Ehlers-Danlos syndrome, cardiac valvular type

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, ClinGen, PanelApp Australia, Orphanet, G2P
• combined osteogenesis imperfecta and Ehlers-Danlos syndrome 2

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen, Ambry Genetics
• Ehlers-Danlos/osteogenesis imperfecta syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• high bone mass osteogenesis imperfecta

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.01316752 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 rank	MANE	Protein	UniProt
COL1A2	NM_000089.4	c.279+2T>C		splice_donor_variant, intron_variant	Intron 6 of 51	ENST00000297268.11	NP_000080.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL1A2	ENST00000297268.11	c.279+2T>C		splice_donor_variant, intron_variant	Intron 6 of 51	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

African (AFR) AF: 0.00 AC: 0 AN: 32770

American (AMR) AF: 0.00 AC: 0 AN: 44076

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25336

East Asian (EAS) AF: 0.00 AC: 0 AN: 38206

South Asian (SAS) AF: 0.00 AC: 0 AN: 84154

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51090

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4968

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1096478

Other (OTH) AF: 0.00 AC: 0 AN: 58912

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

Jan 01, 1994

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

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

Feb 13, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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
PhyloP100		5.6
GERP RS		5.4
Mutation Taster		=0/100	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs72656357; hg19: chr7-94030934;