19-18786051-C-T

Variant names:

• chr19-18786051-C-T
• rs137852651
• NM_000095.3:c.1403G>A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000095.3(COMP):​c.1403G>A​(p.Cys468Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C468R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COMP NM_000095.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:2
• Conservation: PhyloP100: 7.76
• Publications: 3 publications found

Genes affected

COMP (HGNC:2227): (cartilage oligomeric matrix protein) The protein encoded by this gene is a noncollagenous extracellular matrix (ECM) protein. It consists of five identical glycoprotein subunits, each with EGF-like and calcium-binding (thrombospondin-like) domains. Oligomerization results from formation of a five-stranded coiled coil and disulfides. Binding to other ECM proteins such as collagen appears to depend on divalent cations. Contraction or expansion of a 5 aa aspartate repeat and other mutations can cause pseudochondroplasia (PSACH) and multiple epiphyseal dysplasia (MED). [provided by RefSeq, Jul 2016]

COMP Gene-Disease associations (from GenCC):

• multiple epiphyseal dysplasia

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• pseudoachondroplasia

  Inheritance: AD, Unknown Classification: DEFINITIVE, STRONG, SUPPORTIVE, LIMITED Submitted by: ClinGen, Orphanet, Labcorp Genetics (formerly Invitae), Illumina
• multiple epiphyseal dysplasia type 1

  Inheritance: AD Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000095.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-18786052-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 2862149.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 127 curated pathogenic missense variants (we use a threshold of 10). The gene has 12 curated benign missense variants. Gene score misZ: 1.78 (below the threshold of 3.09). Trascript score misZ: 1.5018 (below the threshold of 3.09). GenCC associations: The gene is linked to pseudoachondroplasia, multiple epiphyseal dysplasia type 1, multiple epiphyseal dysplasia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COMP	NM_000095.3	c.1403G>A	p.Cys468Tyr	missense_variant	Exon 13 of 19	ENST00000222271.7	NP_000086.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COMP	ENST00000222271.7	c.1403G>A	p.Cys468Tyr	missense_variant	Exon 13 of 19	1	NM_000095.3	ENSP00000222271.2
COMP	ENST00000542601.6	c.1304G>A	p.Cys435Tyr	missense_variant	Exon 12 of 18	1		ENSP00000439156.2
COMP	ENST00000425807.1	c.1244G>A	p.Cys415Tyr	missense_variant	Exon 12 of 18	2		ENSP00000403792.1
COMP	ENST00000612179.1	n.*67G>A		downstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pseudoachondroplastic spondyloepiphyseal dysplasia syndrome Pathogenic:1

Jul 01, 1995

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not specified Uncertain:1

May 04, 2022

Mendelics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Jul 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 COMP protein function. ClinVar contains an entry for this variant (Variation ID: 9184). This missense change has been observed in individual(s) with pseudoachondroplasia (PMID: 7670471). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 468 of the COMP protein (p.Cys468Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	.;D;.
Eigen	Pathogenic	0.80
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.87	D
MutationAssessor	Pathogenic	3.5	.;H;.
PhyloP100		7.8
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-9.6	D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	.;D;.
Vest4		0.97
MutPred		0.87		.;Gain of phosphorylation at C468 (P = 0.0065);.;
MVP		0.97
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.99
gMVP		0.96
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs137852651; hg19: chr19-18896861;