chr17-50197198-A-AG

Position:

• chr17-50197198-A-AG

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000088.4(COL1A1):​c.731_732insC​(p.Gly245TrpfsTer42) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL1A1 NM_000088.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.81

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 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-50197198-A-AG is Pathogenic according to our data. Variant chr17-50197198-A-AG is described in ClinVar as [Pathogenic]. Clinvar id is 456794.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL1A1	NM_000088.4	c.731_732insC	p.Gly245TrpfsTer42	frameshift_variant	10/51	ENST00000225964.10
COL1A1	XM_005257058.5	c.731_732insC	p.Gly245TrpfsTer42	frameshift_variant	10/49
COL1A1	XM_005257059.5	c.731_732insC	p.Gly245TrpfsTer42	frameshift_variant	10/38
COL1A1	XM_011524341.2	c.731_732insC	p.Gly245TrpfsTer42	frameshift_variant	10/48

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL1A1	ENST00000225964.10	c.731_732insC	p.Gly245TrpfsTer42	frameshift_variant	10/51	1	NM_000088.4	P1
COL1A1	ENST00000495677.1	n.458_459insC		non_coding_transcript_exon_variant	5/8	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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 25, 2017

While this particular variant has not been reported in the literature, loss-of-function variants in COL1A1 are known to be pathogenic (PMID: 9443882, 9295084, 7942841). This sequence change inserts 1 nucleotide in exon 10 of the COL1A1 mRNA (c.731_732insC), causing a frameshift at codon 245. This creates a premature translational stop signal (p.Gly245Trpfs*42) and is expected to result in an absent or disrupted protein product. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1555574553; hg19: chr17-48274559;