NM_000095.3:c.1489+2T>A

Variant names:

• chr19-18785963-A-T
• rs1131692038
• NM_000095.3:c.1489+2T>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_000095.3(COMP):​c.1489+2T>A variant causes a splice donor, intron 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: COMP NM_000095.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.16
• 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):

• 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 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3, offset of 23, new splice context is: gcgGTgggg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COMP	NM_000095.3	c.1489+2T>A		splice_donor_variant, intron_variant	Intron 13 of 18	ENST00000222271.7	NP_000086.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COMP	ENST00000222271.7	c.1489+2T>A		splice_donor_variant, intron_variant	Intron 13 of 18	1	NM_000095.3	ENSP00000222271.2
COMP	ENST00000542601.6	c.1390+2T>A		splice_donor_variant, intron_variant	Intron 12 of 17	1		ENSP00000439156.2
COMP	ENST00000425807.1	c.1330+2T>A		splice_donor_variant, intron_variant	Intron 12 of 17	2		ENSP00000403792.1
COMP	ENST00000612179.1	n.*155T>A		downstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Pseudoachondroplastic spondyloepiphyseal dysplasia syndrome;C1838280:Multiple epiphyseal dysplasia type 1 Uncertain:1

Jun 12, 2017

Shenzhen Institute of Pediatrics, Shenzhen Children's Hospital

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	-0.050
CADD	Pathogenic	30
DANN	Uncertain	0.98
Eigen	Pathogenic	0.76
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.2
GERP RS		4.0
Mutation Taster		=18/82	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.87
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.43		Position offset: 33
DS_DL_spliceai		0.99		Position offset: 2

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

Other links and lift over

dbSNP: rs1131692038; hg19: chr19-18896773;