17-50197045-C-G

Variant names:

• chr17-50197045-C-G
• rs72645321
• NM_000088.4:c.769G>C

Variant summary

Our verdict is Pathogenic. The variant received 21 ACMG points: 21P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000088.4(COL1A1):​c.769G>C​(p.Gly257Arg) 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. 12/20 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. G257E) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.87
• Publications: 0 publications found

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]

COL1A1 Gene-Disease associations (from GenCC):

• Caffey disease

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), G2P, ClinGen
• combined osteogenesis imperfecta and Ehlers-Danlos syndrome 1

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

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• Ehlers-Danlos syndrome, arthrochalasia type

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, PanelApp Australia, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen
• 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, ClinGen
• osteogenesis imperfecta type 3

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

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet, ClinGen
• Ehlers-Danlos syndrome, classic type, 1

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• Ehlers-Danlos syndrome, classic type

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• 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: Pathogenic. The variant received 21 ACMG points.

• PS1: Transcript NM_000088.4 (COL1A1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 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 chr17-50197044-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 456796.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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 high bone mass osteogenesis imperfecta, Ehlers-Danlos syndrome, arthrochalasia type, combined osteogenesis imperfecta and Ehlers-Danlos syndrome 1, Caffey disease, osteogenesis imperfecta type 4, osteogenesis imperfecta type 3, Ehlers-Danlos syndrome, classic type, Ehlers-Danlos syndrome, osteogenesis imperfecta type 2, osteogenesis imperfecta type 1, Ehlers-Danlos syndrome, classic type, 1, Ehlers-Danlos/osteogenesis imperfecta syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 17-50197045-C-G is Pathogenic according to our data. Variant chr17-50197045-C-G is described in ClinVar as Pathogenic. ClinVar VariationId is 1451481.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL1A1	NM_000088.4	c.769G>C	p.Gly257Arg	missense_variant	Exon 11 of 51	ENST00000225964.10	NP_000079.2
COL1A1	XM_011524341.2	c.769G>C	p.Gly257Arg	missense_variant	Exon 11 of 48		XP_011522643.1
COL1A1	XM_005257058.5	c.769G>C	p.Gly257Arg	missense_variant	Exon 11 of 49		XP_005257115.2
COL1A1	XM_005257059.5	c.769G>C	p.Gly257Arg	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.769G>C	p.Gly257Arg	missense_variant	Exon 11 of 51	1	NM_000088.4	ENSP00000225964.6
COL1A1	ENST00000495677.1	n.496G>C		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:1

Revision: criteria provided, single submitter

Submissions by phenotype

Osteogenesis imperfecta type I Pathogenic:1

Apr 21, 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 257 of the COL1A1 protein (p.Gly257Arg). 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 missense change has been observed in individual(s) with osteogenesis imperfecta (PMID: 31447884, Invitae). 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. 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, 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	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	30
DANN	Uncertain	1.0
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Uncertain	0.97	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
PhyloP100		7.9
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-6.4	D
REVEL	Pathogenic	1.0
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		1.0
MutPred		0.99		Gain of MoRF binding (P = 0.0066);
MVP		0.99
MPC		0.67
ClinPred		1.0	D
GERP RS		5.1
gMVP		1.0
Mutation Taster		=1/99	disease causing

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

Other links and lift over

dbSNP: rs72645321; hg19: chr17-48274406;