rs1555166295

Positions:

• chr12-47982104-TA-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_Moderate PM2 PP3 PP5_Moderate

The ENST00000380518.8(COL2A1):​c.2355+2del variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL2A1 ENST00000380518.8 splice_donor
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.19

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 Likely_pathogenic. Variant got 7 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.01187276 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.3, offset of -44, new splice context is: ttgGTgaga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Multiple lines of computational evidence support a deleterious effect 2: max_spliceai, phyloP100way_vertebrate [when was below the threshold]
• PP5: Variant 12-47982104-TA-T is Pathogenic according to our data. Variant chr12-47982104-TA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 547257.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL2A1	NM_001844.5	c.2355+2del		splice_donor_variant		ENST00000380518.8	NP_001835.3
LOC105369752	XR_944910.2	n.219-310del		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL2A1	ENST00000380518.8	c.2355+2del		splice_donor_variant		1	NM_001844.5	ENSP00000369889	P1
COL2A1	ENST00000337299.7	c.2148+2del		splice_donor_variant		1		ENSP00000338213
COL2A1	ENST00000493991.5	n.1281del		non_coding_transcript_exon_variant	18/37	2
COL2A1	ENST00000483376.1	n.533+2del		splice_donor_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Stickler syndrome type 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Nov 01, 2016

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555166295; hg19: chr12-48375887;