chr12-47987611-G-C

Position:

• chr12-47987611-G-C

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BP7 BS2

The ENST00000380518.8(COL2A1):​c.1221C>G​(p.Ser407=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000621 in 1,611,112 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. S407S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: COL2A1 ENST00000380518.8 splice_region, synonymous
• Scores: Splicing: ADA: 0.00002409
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.28

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]

ACMG classification

Verdict is Benign. Variant got -7 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.32).
• BP7: Synonymous conserved (PhyloP=-1.28 with no splicing effect.
• BS2: High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL2A1	NM_001844.5	c.1221C>G	p.Ser407=	splice_region_variant, synonymous_variant	19/54	ENST00000380518.8	NP_001835.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL2A1	ENST00000380518.8	c.1221C>G	p.Ser407=	splice_region_variant, synonymous_variant	19/54	1	NM_001844.5	ENSP00000369889	P1
COL2A1	ENST00000337299.7	c.1014C>G	p.Ser338=	splice_region_variant, synonymous_variant	18/53	1		ENSP00000338213
COL2A1	ENST00000493991.5	n.145C>G		splice_region_variant, non_coding_transcript_exon_variant	2/37	2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151936 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000204 AC: 5 AN: 244650 Hom.: 0 AF XY: 0.0000151 AC XY: 2 AN XY: 132558

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000146

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000617 AC: 9 AN: 1459176 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 725652

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.000180

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151936 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74182

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000656

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 24, 2023

ClinVar contains an entry for this variant (Variation ID: 1990601). This sequence change affects codon 407 of the COL2A1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the COL2A1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs150865922, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with COL2A1-related conditions. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.32
CADD	Benign	2.5
DANN	Benign	0.87
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000024
dbscSNV1_RF	Benign	0.16
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: rs150865922; hg19: chr12-48381394;