chr19-18783126-C-T

Position:

• chr19-18783126-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000095.3(COMP):​c.2155G>A​(p.Gly719Ser) 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. 12/20 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G719D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COMP NM_000095.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.75

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a region_of_interest Mediates cell survival and induction of the IAP family of survival proteins (size 230) in uniprot entity COMP_HUMAN there are 18 pathogenic changes around while only 0 benign (100%) 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 chr19-18783125-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 19-18783126-C-T is Pathogenic according to our data. Variant chr19-18783126-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 40997.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-18783126-C-T is described in Lovd as [Pathogenic]. Variant chr19-18783126-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COMP	NM_000095.3	c.2155G>A	p.Gly719Ser	missense_variant	18/19	ENST00000222271.7	NP_000086.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COMP	ENST00000222271.7	c.2155G>A	p.Gly719Ser	missense_variant	18/19	1	NM_000095.3	ENSP00000222271.2
COMP	ENST00000542601.6	c.2056G>A	p.Gly686Ser	missense_variant	17/18	1		ENSP00000439156.2
COMP	ENST00000425807.1	c.1996G>A	p.Gly666Ser	missense_variant	17/18	2		ENSP00000403792.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

Alfa AF: 0.00215 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jul 18, 2023	Not observed in large population cohorts (gnomAD); 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: 25525159, 21922596, 15756302) -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 28, 2022	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Gly719 amino acid residue in COMP. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11746044, 17394206). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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: 40997). This missense change has been observed in individuals with clinical features of pseudoachondroplasia (PMID: 15756302, 21922596; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 719 of the COMP protein (p.Gly719Ser). -

Pseudoachondroplastic spondyloepiphyseal dysplasia syndrome Other:1

not provided, no classification provided

literature only

GeneReviews

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	.;D;.
Eigen	Pathogenic	0.75
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	.;M;.
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-5.7	D;D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	.;D;.
Vest4		0.98
MutPred		0.99		.;Loss of methylation at R718 (P = 0.0495);.;
MVP		0.95
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.94
gMVP		0.84

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: rs312262904; hg19: chr19-18893936;