17-50196172-C-G

Variant names:

• chr17-50196172-C-G
• rs1555574303
• NM_000088.4:c.985G>C

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000088.4(COL1A1):​c.985G>C​(p.Gly329Arg) 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 Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.84

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 15 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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 17-50196172-C-G is Pathogenic according to our data. Variant chr17-50196172-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 450546.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL1A1	NM_000088.4	c.985G>C	p.Gly329Arg	missense_variant	Exon 15 of 51	ENST00000225964.10	NP_000079.2
COL1A1	XM_005257058.5	c.985G>C	p.Gly329Arg	missense_variant	Exon 15 of 49		XP_005257115.2
COL1A1	XM_011524341.2	c.957+142G>C		intron_variant	Intron 14 of 47		XP_011522643.1
COL1A1	XM_005257059.5	c.957+142G>C		intron_variant	Intron 14 of 37		XP_005257116.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL1A1	ENST00000225964.10	c.985G>C	p.Gly329Arg	missense_variant	Exon 15 of 51	1	NM_000088.4	ENSP00000225964.6
COL1A1	ENST00000485870.1	n.310G>C		non_coding_transcript_exon_variant	Exon 2 of 2	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Jul 20, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The G329R variant in the COL1A1 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. G329R occurs in the triple helical domain and replaces the Glycine in the canonical Gly-X-Y repeat. Variants in these Glycines result in poor winding of the collagen triple helix and a less functional protein. The G329R variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The G329R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. Missense variants in nearby Glycine residues (G326D, G332R, G332A) have been reported in the Human Gene Mutation Database in association with osteogenesis imperfecta (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, we interpret G329R as a pathogenic variant. -

Nov 09, 2018

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant disrupts a glycine residue in the canonical Gly-X-Y repeats of the triple helix domain, which are required for stability and structure of this protein. Therefore it is expected to severely affect the function of the protein. Found in at least one symptomatic patient, and not found in general population data. -

Infantile cortical hyperostosis;C0023931:Osteogenesis imperfecta type I;C0029458:Postmenopausal osteoporosis;C0268358:Osteogenesis imperfecta, perinatal lethal;C0268362:Osteogenesis imperfecta type III;C0268363:Osteogenesis imperfecta with normal sclerae, dominant form;C4551623:Ehlers-Danlos syndrome, arthrochalasia type Pathogenic:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	28
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.97	D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-6.0	D
REVEL	Pathogenic	1.0
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.99
MutPred		1.0		Gain of methylation at G329 (P = 0.0088);
MVP		0.99
MPC		0.67
ClinPred		1.0	D
GERP RS		5.1
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1555574303; hg19: chr17-48273533;