rs72658194

Variant names:

• chr7-94423074-G-A
• rs72658194
• NM_000089.4:c.2521G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PP2 PP3_Strong PP5_Moderate

The NM_000089.4(COL1A2):​c.2521G>A​(p.Gly841Ser) variant causes a missense 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. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A2 NM_000089.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 10.0

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 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the COL1A2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 437 curated pathogenic missense variants (we use a threshold of 10). The gene has 17 curated benign missense variants. Gene score misZ: 2.1491 (below the threshold of 3.09). Trascript score misZ: 3.5344 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.994
• PP5: Variant 7-94423074-G-A is Pathogenic according to our data. Variant chr7-94423074-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 568053.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.2521G>A	p.Gly841Ser	missense_variant	Exon 40 of 52	ENST00000297268.11	NP_000080.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL1A2	ENST00000297268.11	c.2521G>A	p.Gly841Ser	missense_variant	Exon 40 of 52	1	NM_000089.4	ENSP00000297268.6
COL1A2	ENST00000481570.5	n.604G>A		non_coding_transcript_exon_variant	Exon 1 of 8	2
COL1A2	ENST00000497316.5	n.918G>A		non_coding_transcript_exon_variant	Exon 9 of 9	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Apr 12, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine with serine at codon 841 of the COL1A2 protein (p.Gly841Ser). The glycine residue is highly conserved and there is a small physicochemical difference between glycine and serine. This variant is not present in population databases (ExAC no frequency). This variant has been reported to segregate in a family affected with severe, progressively deforming osteogenesis imperfecta  (PMID: 9099837). The variant is also known as p.Gly751Ser in the literature. Experimental studies have shown that this missense change affects the thermal stability of the collagen I and produces unstable collagen I (PMID: 9099837). 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, missense variants at these glycine residues are significantly enriched in individuals with disease (PMID: 9016532, 17078022) compared to the general population (ExAC). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	3.6	H;.
PrimateAI	Uncertain	0.72	T
PROVEAN	Pathogenic	-5.3	D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;.
Sift4G	Uncertain	0.0050	D;D
Polyphen		1.0	D;.
Vest4		0.98
MutPred		1.0		Gain of glycosylation at G841 (P = 0.0058);.;
MVP		1.0
MPC		0.21
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.92
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs72658194; hg19: chr7-94052386; COSMIC: COSV51962355; COSMIC: COSV51962355;