17-50195330-C-T

Position:

• chr17-50195330-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000088.4(COL1A1):​c.1201G>A​(p.Gly401Ser) 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. 13/23 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. G401C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 missense, splice_region
• Scores: Splicing: ADA: 0.9988
• 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.

• 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 gene, where missense usually causes diseases (based on misZ statistic), COL1A1. . Gene score misZ: 3.5319 (greater than the threshold 3.09). Trascript score misZ: 5.7733 (greater than threshold 3.09). The gene has 368 curated pathogenic missense variants (we use a threshold of 10). The gene has 98 curated benign missense variants. GenCC has associacion of the gene with 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, 0.992
• PP5: Variant 17-50195330-C-T is Pathogenic according to our data. Variant chr17-50195330-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 425596.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-50195330-C-T is described in Lovd as [Pathogenic]. Variant chr17-50195330-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL1A1	NM_000088.4	c.1201G>A	p.Gly401Ser	missense_variant, splice_region_variant	19/51	ENST00000225964.10	NP_000079.2
COL1A1	XM_011524341.2	c.1003G>A	p.Gly335Ser	missense_variant, splice_region_variant	16/48		XP_011522643.1
COL1A1	XM_005257058.5	c.1201G>A	p.Gly401Ser	missense_variant, splice_region_variant	19/49		XP_005257115.2
COL1A1	XM_005257059.5	c.957+984G>A		intron_variant			XP_005257116.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL1A1	ENST00000225964.10	c.1201G>A	p.Gly401Ser	missense_variant, splice_region_variant	19/51	1	NM_000088.4	ENSP00000225964.6
COL1A1	ENST00000471344.1	n.145G>A		splice_region_variant, non_coding_transcript_exon_variant	3/8	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

clinical testing

Department of Medical Sciences, Uppsala University

-

- -

Osteogenesis imperfecta type I Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 27, 2022

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 401 of the COL1A1 protein (p.Gly401Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with osteogenesis imperfecta (PMID: 26177859, 30715774, 31737030). ClinVar contains an entry for this variant (Variation ID: 425596). 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 C55"). Studies have shown that this missense change does not affect mRNA splicing (PMID: 31737030). 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	0.89
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-4.4	D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.98
MutPred		0.99		Gain of glycosylation at G401 (P = 0.0113);
MVP		0.99
MPC		0.56
ClinPred		1.0	D
GERP RS		5.6
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.96
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.22		Position offset: 30

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

Publications

LitVar

Other links and lift over

dbSNP: rs72648322; hg19: chr17-48272691;