rs121912893

Positions:

• chr12-47983721-G-A
• chr12-47983721-G-T

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.1957C>T​(p.Arg653Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: COL2A1 NM_001844.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8 O:1
• Conservation: PhyloP100: 2.79

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 12-47983721-G-A is Pathogenic according to our data. Variant chr12-47983721-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 17395.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-47983721-G-A is described in Lovd as [Pathogenic]. Variant chr12-47983721-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.1957C>T	p.Arg653Ter	stop_gained	30/54	ENST00000380518.8	NP_001835.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL2A1	ENST00000380518.8	c.1957C>T	p.Arg653Ter	stop_gained	30/54	1	NM_001844.5	ENSP00000369889	P1
COL2A1	ENST00000337299.7	c.1750C>T	p.Arg584Ter	stop_gained	29/53	1		ENSP00000338213
COL2A1	ENST00000483376.1	n.135C>T		non_coding_transcript_exon_variant	1/8	5
COL2A1	ENST00000493991.5	n.881C>T		non_coding_transcript_exon_variant	13/37	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1442782 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 715680

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Blueprint Genetics	Nov 30, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Oct 22, 2021	Reported in multiple individuals with Stickler syndrome referred for genetic testing at GeneDx and in published literature (Wilkin et al., 2000; Liberfarb et al., 2003; Richards et al., 2005; Hoornaert et al., 2010; Richards et al., 2010; Savasta et al., 2015); Estimated to account for 2% of molecularly confirmed cases of Stickler syndrome type 1 (Barat-Houari et al., 2016); Not observed in large population cohorts (gnomAD); 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; Reported in ClinVar as pathogenic (ClinVar Variant ID# 17395; ClinVar); Also known as R453*; This variant is associated with the following publications: (PMID: 20179744, 20301479, 20513134, 16752401, 10982970, 26443184, 12544472, 12939326, 24164106, 25809783, 29453956, 15671297, 26747767) -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 18, 2023	This sequence change creates a premature translational stop signal (p.Arg653*) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with Stickler syndrome (PMID: 12544472). This variant is also known as p.R453X. ClinVar contains an entry for this variant (Variation ID: 17395). For these reasons, this variant has been classified as Pathogenic. -

Stickler syndrome type 1 Pathogenic:2 Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Sep 01, 2003	- -
not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center	Nov 10, 2023	PVS1, PS4, PM2 -

Autosomal dominant rhegmatogenous retinal detachment Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Sep 01, 2003

- -

Stickler syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Clinical Biomedical Laboratory, Shriners Hospital For Children - Canada

Aug 08, 2024

This variant is predicted to introduce a premature termination codon in COL2A1. Premature termination codons in COL2A1 are a known cause of Stickler syndrome (PMID: 10982970). This is expected to lead to degradation of the affected transcript and haploinsufficiency. This variant is absent from general population databases (Genome Aggregation Database v2.1.1), indicating it is not a common polymorphism. This specific variant is reported in ClinVar (Variation ID: 17395) as pathogenic from multiple submitters for various conditions including Stickler syndrome type 1. This specific variant has been reported in the literature (PMID: 20179744) and in the Leiden Open Variation database V3. -

Achondrogenesis type II;C0265279:Kniest dysplasia;C0432214:Namaqualand hip dysplasia;C0796173:Spondyloperipheral dysplasia;C1442965:Legg-Calve-Perthes disease;C1835437:Platyspondylic dysplasia, Torrance type;C1836080:Stickler syndrome, type I, nonsyndromic ocular;C1836683:Spondyloepiphyseal dysplasia with metatarsal shortening;C1851536:Multiple epiphyseal dysplasia, Beighton type;C2020284:Stickler syndrome type 1;C2745959:Spondyloepiphyseal dysplasia congenita;C4225273:Spondyloepiphyseal dysplasia, Stanescu type;C4551562:Avascular necrosis of femoral head, primary, 1;C4759767:Spondylometaphyseal dysplasia Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

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	Pathogenic	0.81
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.82	D
MutationTaster	Benign	1.0	A;A
Vest4		0.89
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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: rs121912893; hg19: chr12-48377504; COSMIC: COSV61532466;