rs121912865

chr12-47982886-G-A

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_001844.5(COL2A1):c.2155C>T(p.Arg719Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,612,750 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R719H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: COL2A1 NM_001844.5 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 2.28

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]

LOC105369752 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 3 uncertain in NM_001844.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL2A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.961
• PP5: Variant 12-47982886-G-A is Pathogenic according to our data. Variant chr12-47982886-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 17353.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-47982886-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL2A1	NM_001844.5	c.2155C>T	p.Arg719Cys	missense_variant	33/54	ENST00000380518.8
LOC105369752	XR_944910.2			downstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL2A1	ENST00000380518.8	c.2155C>T	p.Arg719Cys	missense_variant	33/54	1	NM_001844.5	P1
COL2A1	ENST00000337299.7	c.1948C>T	p.Arg650Cys	missense_variant	32/53	1
COL2A1	ENST00000483376.1	n.333C>T		non_coding_transcript_exon_variant	4/8	5
COL2A1	ENST00000493991.5	n.1079C>T		non_coding_transcript_exon_variant	16/37	2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152156 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460594 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726614

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152156 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74310

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000202 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Namaqualand hip dysplasia Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 01, 1998	- -
Pathogenic, criteria provided, single submitter	clinical testing	Zankl Lab, University of Sydney	Mar 15, 2023	This variant (sometimes referred to as p.Arg519Cys in older literature) is very rare in the general population and has been identified in several other families with a similar phenotype (PMID: 16155195, 1975693, 1985108, 26443184). Type II collagen is a major constituent of articular cartilage. The variant leads to substitution of an Arginine with a Cysteine molecule in the triple helix domain of type II collagen. Functional studies suggest that this leads to abnormal assembly of type II collagen fibrils (PMID: 10372559). -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jul 27, 2023	This missense change has been observed in individual(s) with autosomal dominant osteoarthritis with mild chondrodysplasia or early-onset osteoarthritis (PMID: 1975693, 1985108, 26443184). It has also been observed to segregate with disease in related individuals. For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt COL2A1 protein function. ClinVar contains an entry for this variant (Variation ID: 17353). This variant is also known as p.Arg519Cys. This variant is present in population databases (rs121912865, gnomAD 0.007%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 719 of the COL2A1 protein (p.Arg719Cys). -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Dec 29, 2022	Also known as p.Arg519Cys; Not observed at significant frequency in large population cohorts (gnomAD); Occurs in the triple helical domain at the Y position in the canonical Gly-X-Y repeat; although this variant may have an effect on normal protein folding and function, missense substitution at the Y position is not a common mechanism of disease (HGMD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 32071555, 32510848, 32901917, 11708863, 26443184, 1985108, 1975693) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
Cadd	Pathogenic	28
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D;.
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	M;.
MutationTaster	Benign	1.0	A;A
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.80
MutPred		0.88		Gain of catalytic residue at P718 (P = 0.0069);.;
MVP		0.97
MPC		2.1
ClinPred		0.99	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.70
gMVP		0.90

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: rs121912865; hg19: chr12-48376669;