chr7-94409323-G-T

Position:

• chr7-94409323-G-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000089.4(COL1A2):​c.794G>T​(p.Gly265Val) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. 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 predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G265C) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A2 NM_000089.4 missense, splice_region
• Scores: Splicing: ADA: 0.8250
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.86

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 Pathogenic. Variant got 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-94409322-G-T is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), COL1A2. . Gene score misZ 2.1491 (greater than the threshold 3.09). Trascript score misZ 3.5344 (greater than threshold 3.09). GenCC has associacion of gene with Ehlers-Danlos/osteogenesis imperfecta syndrome, Ehlers-Danlos syndrome, cardiac valvular type, ehlers-danlos syndrome, arthrochalasia type, 2, Ehlers-Danlos syndrome, arthrochalasia type, osteogenesis imperfecta type 3, high bone mass osteogenesis imperfecta, combined osteogenesis imperfecta and Ehlers-Danlos syndrome 2, osteogenesis imperfecta type 4, osteogenesis imperfecta type 2, osteogenesis imperfecta type 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 7-94409323-G-T is Pathogenic according to our data. Variant chr7-94409323-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1457226.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL1A2	NM_000089.4	c.794G>T	p.Gly265Val	missense_variant, splice_region_variant	17/52	ENST00000297268.11	NP_000080.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL1A2	ENST00000297268.11	c.794G>T	p.Gly265Val	missense_variant, splice_region_variant	17/52	1	NM_000089.4	ENSP00000297268.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

COL1A2-related disorder Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 26, 2022

The COL1A2 c.794G>T variant is predicted to result in the amino acid substitution p.Gly265Val. To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Alternate substitutions impacting the same amino acid (p.Gly265Arg, p.Gly265Asp) have been reported in patients with osteogenesis imperfecta (for example, see Supplemental Table 1 in Lindahl et al. 2015. PubMed ID: 26177859; Supplemental Table 1 in Bardai et al. 2016. PubMed ID: 27509835). The p.Gly265 is located in the conserved Gly-Xaa-Yaa triple helical domain where substitutions of a glycine are usually pathogenic (Marini et al. 2007. PubMed ID: 17078022). We classify this variant as likely pathogenic. -

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

Apr 24, 2021

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the triple helix domain of COL1A2. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236). In COL1A2, variants affecting these glycine residues are significantly enriched in individuals with disease (PMID: 9016532, 17078022) compared to the general population (ExAC). 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: "Deleterious"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C65"). This variant has been observed in individual(s) with autosomal dominant osteogenesis imperfecta (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with valine at codon 265 of the COL1A2 protein (p.Gly265Val). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and valine. This variant disrupts the p.Gly265 amino acid residue in COL1A2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 26177859, 27509835, 9240878). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	29
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.80	D;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.8	H;.
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-7.2	D;.
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;.
Vest4		0.97
MutPred		0.99		Gain of sheet (P = 0.0149);.;
MVP		0.98
MPC		0.32
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.95
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.83
dbscSNV1_RF	Benign	0.67
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr7-94038635;