19-18783127-C-T

Variant names:

• chr19-18783127-C-T
• rs780066431
• NM_000095.3:c.2154G>A
• COMP p.Arg718Arg

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_000095.3(COMP):​c.2154G>A​(p.Arg718Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R718R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: COMP NM_000095.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.379
• Publications: 0 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):

• COMP-related skeletal dysplasia

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• multiple epiphyseal dysplasia

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

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

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

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.4).
• BP7: Synonymous conserved (PhyloP=-0.379 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000095.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COMP	NM_000095.3	MANE Select	c.2154G>A	p.Arg718Arg	synonymous	Exon 18 of 19	NP_000086.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COMP	ENST00000222271.7	TSL:1 MANE Select	c.2154G>A	p.Arg718Arg	synonymous	Exon 18 of 19	ENSP00000222271.2	P49747-1
	COMP	ENST00000542601.6	TSL:1	c.2055G>A	p.Arg685Arg	synonymous	Exon 17 of 18	ENSP00000439156.2	G3XAP6
	COMP	ENST00000944187.1		c.2241G>A	p.Arg747Arg	synonymous	Exon 19 of 20	ENSP00000614246.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00 AC: 0 AN: 248104 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1458780 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 725742

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50368

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111976

Other (OTH) AF: 0.00 AC: 0 AN: 60378

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.40
CADD	Benign	7.8
DANN	Benign	0.89
PhyloP100		-0.38

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs780066431;

hg19: chr19-18893937;

COSMIC: COSV99721537;

COSMIC: COSV99721537;