rs121912869

Positions:

• chr12-47995904-G-A

Variant summary

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

The NM_001844.5(COL2A1):​c.625C>T​(p.Arg209*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,318 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL2A1 NM_001844.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.70

Genes affected

COL2A1 (HGNC:2200): (collagen type II alpha 1 chain) This gene encodes the alpha-1 chain of type II collagen, a fibrillar collagen found in cartilage and the vitreous humor of the eye. Mutations in this gene are associated with achondrogenesis, chondrodysplasia, early onset familial osteoarthritis, SED congenita, Langer-Saldino achondrogenesis, Kniest dysplasia, Stickler syndrome type I, and spondyloepimetaphyseal dysplasia Strudwick type. In addition, defects in processing chondrocalcin, a calcium binding protein that is the C-propeptide of this collagen molecule, are also associated with chondrodysplasia. There are two transcripts identified for this gene. [provided by RefSeq, Jul 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 12-47995904-G-A is Pathogenic according to our data. Variant chr12-47995904-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 17360.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-47995904-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL2A1	NM_001844.5	c.625C>T	p.Arg209*	stop_gained	9/54	ENST00000380518.8	NP_001835.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL2A1	ENST00000380518.8	c.625C>T	p.Arg209*	stop_gained	9/54	1	NM_001844.5	ENSP00000369889.3
COL2A1	ENST00000337299.7	c.418C>T	p.Arg140*	stop_gained	8/53	1		ENSP00000338213.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461318 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727002

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 19, 2023	For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 17360). This variant is also known as p.Arg9X. This premature translational stop signal has been observed in individual(s) with clinical features of Stickler syndrome (PMID: 8434604). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Arg209*) in the COL2A1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in COL2A1 are known to be pathogenic (PMID: 20179744). -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 07, 2024	Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 34680973, 25525159, 20179744, 15895462, 26443184, 8434604) -

Stickler syndrome type 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jan 01, 1993

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.68	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	46
DANN	Uncertain	1.0
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.93	D
Vest4		0.81
GERP RS		2.8

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: rs121912869; hg19: chr12-48389687;