17-50197018-C-T

Variant names:

• chr17-50197018-C-T
• NM_000088.4:c.796G>A

Variant summary

Our verdict is Pathogenic. Variant got 23 ACMG points: 23P and 0B. PS1 PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000088.4(COL1A1):​c.796G>A​(p.Gly266Arg) 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. 11/19 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G266E) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.87

Genes affected

COL1A1 (HGNC:2197): (collagen type I alpha 1 chain) This gene encodes the pro-alpha1 chains 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 VIIA, Ehlers-Danlos syndrome Classical type, Caffey Disease and idiopathic osteoporosis. Reciprocal translocations between chromosomes 17 and 22, where this gene and the gene for platelet-derived growth factor beta are located, are associated with a particular type of skin tumor called dermatofibrosarcoma protuberans, resulting from unregulated expression of the growth factor. Two 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 23 ACMG points.

• PS1: Transcript NM_000088.4 (COL1A1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 456797
• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 2 uncertain in NM_000088.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP2: Missense variant in the COL1A1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 368 curated pathogenic missense variants (we use a threshold of 10). The gene has 98 curated benign missense variants. Gene score misZ: 3.5319 (above the threshold of 3.09). Trascript score misZ: 5.7733 (above the threshold of 3.09). GenCC associations: The gene is linked to Caffey disease, Ehlers-Danlos/osteogenesis imperfecta syndrome, combined osteogenesis imperfecta and Ehlers-Danlos syndrome 1, Ehlers-Danlos syndrome, arthrochalasia type, osteogenesis imperfecta type 3, Ehlers-Danlos syndrome, classic type, 1, high bone mass osteogenesis imperfecta, osteogenesis imperfecta type 4, Ehlers-Danlos syndrome, classic type, osteogenesis imperfecta type 2, osteogenesis imperfecta type 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 17-50197018-C-T is Pathogenic according to our data. Variant chr17-50197018-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 1456151.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-50197018-C-T is described in Lovd as [Pathogenic]. Variant chr17-50197018-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL1A1	NM_000088.4	c.796G>A	p.Gly266Arg	missense_variant	Exon 11 of 51	ENST00000225964.10	NP_000079.2
COL1A1	XM_011524341.2	c.796G>A	p.Gly266Arg	missense_variant	Exon 11 of 48		XP_011522643.1
COL1A1	XM_005257058.5	c.796G>A	p.Gly266Arg	missense_variant	Exon 11 of 49		XP_005257115.2
COL1A1	XM_005257059.5	c.796G>A	p.Gly266Arg	missense_variant	Exon 11 of 38		XP_005257116.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL1A1	ENST00000225964.10	c.796G>A	p.Gly266Arg	missense_variant	Exon 11 of 51	1	NM_000088.4	ENSP00000225964.6
COL1A1	ENST00000495677.1	n.523G>A		non_coding_transcript_exon_variant	Exon 6 of 8	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Feb 08, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Occurs in the triple helical domain and replaces a glycine in a canonical Gly-X-Y repeat; missense substitution of a canonical glycine residue is expected to disrupt normal protein folding and function, and this is an established mechanism of disease (PMID: 34007986); Not observed in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 27090748) -

Osteogenesis imperfecta type I Pathogenic:1

Jul 26, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine with arginine at codon 266 of the COL1A1 protein (p.Gly266Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with clinical features of COL1A1-related conditions (PMID: 27090748). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt COL1A1 protein function. This variant disrupts the triple helix domain of COL1A1. 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 COL1A1, variants affecting 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	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	29
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.99	D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-6.6	D
REVEL	Pathogenic	1.0
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Vest4		0.99
MutPred		0.99		Gain of MoRF binding (P = 0.0415);
MVP		0.99
MPC		0.67
ClinPred		1.0	D
GERP RS		5.2
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
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: chr17-48274379;