rs66721653

chr17-50195665-C-Achr17-50195665-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_000088.4(COL1A1):c.1057G>T(p.Gly353Cys) 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. 13/21 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G353S) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 missense, splice_region
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.91

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 11 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 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 chr17-50195665-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 2829583.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant where missense usually causes diseases, COL1A1
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 17-50195665-C-A is Pathogenic according to our data. Variant chr17-50195665-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 17286.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-50195665-C-A is described in Lovd as [Pathogenic]. Variant chr17-50195665-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL1A1	NM_000088.4	c.1057G>T	p.Gly353Cys	missense_variant, splice_region_variant	17/51	ENST00000225964.10
COL1A1	XM_005257058.5	c.1057G>T	p.Gly353Cys	missense_variant, splice_region_variant	17/49
COL1A1	XM_005257059.5	c.957+649G>T		intron_variant
COL1A1	XM_011524341.2	c.958-187G>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL1A1	ENST00000225964.10	c.1057G>T	p.Gly353Cys	missense_variant, splice_region_variant	17/51	1	NM_000088.4	P1
COL1A1	ENST00000471344.1	n.1G>T		non_coding_transcript_exon_variant	1/8	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Osteogenesis imperfecta with normal sclerae, dominant form Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 15, 1991

- -

Osteogenesis imperfecta type I Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jun 04, 2022

For these reasons, this variant has been classified as Pathogenic. 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). 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"). ClinVar contains an entry for this variant (Variation ID: 17286). This missense change has been observed in individual(s) with osteogenesis imperfecta (PMID: 31447884). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 353 of the COL1A1 protein (p.Gly353Cys). -

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	32
Dann	Uncertain	0.99
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Pathogenic	0.91	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.99
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Vest4		0.97
MutPred		1.0		Loss of loop (P = 0.1242);
MVP		0.99
MPC		0.60
ClinPred		1.0	D
GERP RS		5.7
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.010		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: rs66721653; hg19: chr17-48273026;