chr17-50199309-CA-C

Position:

• chr17-50199309-CA-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000088.4(COL1A1):​c.387del​(p.Gly130AlafsTer135) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P129P) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL1A1 NM_000088.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 0.296

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 18 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 17-50199309-CA-C is Pathogenic according to our data. Variant chr17-50199309-CA-C is described in ClinVar as [Pathogenic]. Clinvar id is 456780.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-50199309-CA-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL1A1	NM_000088.4	c.387del	p.Gly130AlafsTer135	frameshift_variant	5/51	ENST00000225964.10
COL1A1	XM_011524341.2	c.387del	p.Gly130AlafsTer135	frameshift_variant	5/48
COL1A1	XM_005257058.5	c.387del	p.Gly130AlafsTer135	frameshift_variant	5/49
COL1A1	XM_005257059.5	c.387del	p.Gly130AlafsTer135	frameshift_variant	5/38

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL1A1	ENST00000225964.10	c.387del	p.Gly130AlafsTer135	frameshift_variant	5/51	1	NM_000088.4	P1
COL1A1	ENST00000507689.1	c.441del	p.Gly148AlafsTer?	frameshift_variant	4/4	2
COL1A1	ENST00000474644.1	n.608del		non_coding_transcript_exon_variant	4/4	3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Osteogenesis imperfecta type I Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Feb 10, 2022	ClinVar contains an entry for this variant (Variation ID: 456780). For these reasons, this variant has been classified as Pathogenic. This variant is also known as p.Pro129Profs*30. This premature translational stop signal has been observed in individual(s) with clinical features of osteogenesis imperfecta (PMID: 31363794). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gly130Alafs*135) in the COL1A1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in COL1A1 are known to be pathogenic (PMID: 7942841, 9295084, 9443882). -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	-	The variant is not observed in the gnomAD v2.1.1 dataset. This frameshift variant is predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported to be associated with COL1A1-related disorder (ClinVar ID: VCV000456780/PMID: 31363794). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555575086; hg19: chr17-48276670;