chr20-62817077-C-T

Position:

• chr20-62817077-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001853.4(COL9A3):​c.13C>T​(p.Arg5Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000505 in 1,386,428 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R5S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000040 (0 hom.)
• Consequence: COL9A3 NM_001853.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.470

Genes affected

COL9A3 (HGNC:2219): (collagen type IX alpha 3 chain) This gene encodes one of the three alpha chains of type IX collagen, the major collagen component of hyaline cartilage. Type IX collagen, a heterotrimeric molecule, is usually found in tissues containing type II collagen, a fibrillar collagen. Mutations in this gene are associated with multiple epiphyseal dysplasia type 3. [provided by RefSeq, Jan 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.24315414).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL9A3	NM_001853.4	c.13C>T	p.Arg5Cys	missense_variant	1/32	ENST00000649368.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL9A3	ENST00000649368.1	c.13C>T	p.Arg5Cys	missense_variant	1/32		NM_001853.4	P1
COL9A3	ENST00000477612.5	n.75-490C>T		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 151286 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000484

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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

GnomAD4 exome AF: 0.00000405 AC: 5 AN: 1235142 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 608938

Gnomad4 AFR exome AF: 0.0000405

Gnomad4 AMR exome AF: 0.00

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: 0.00000301

Gnomad4 OTH exome AF: 0.0000204

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 151286 Hom.: 0 Cov.: 33 AF XY: 0.0000271 AC XY: 2 AN XY: 73858

Gnomad4 AFR AF: 0.0000484

Gnomad4 AMR AF: 0.00

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:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 08, 2023	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. 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 not expected to disrupt COL9A3 protein function. ClinVar contains an entry for this variant (Variation ID: 1315133). This variant has not been reported in the literature in individuals affected with COL9A3-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.02%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 5 of the COL9A3 protein (p.Arg5Cys). -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Feb 06, 2020	Has not been previously published as pathogenic or benign to our knowledge; In silico analysis supports that this missense variant does not alter protein structure/function -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Benign	0.0065	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	18
DANN	Benign	0.95
DEOGEN2	Benign	0.017	T;T
Eigen	Benign	-0.68
Eigen_PC	Benign	-0.72
FATHMM_MKL	Benign	0.078	N
LIST_S2	Benign	0.43	.;T
M_CAP	Pathogenic	0.79	D
MetaRNN	Benign	0.24	T;T
MetaSVM	Benign	-0.47	T
MutationAssessor	Benign	0.90	L;L
MutationTaster	Benign	0.99	N
PrimateAI	Uncertain	0.79	T
PROVEAN	Benign	-1.1	.;N
REVEL	Benign	0.28
Sift	Pathogenic	0.0	.;D
Sift4G	Benign	0.12	.;T
Polyphen		0.61	P;P
Vest4		0.16
MutPred		0.39		Loss of methylation at P5 (P = 0.0126);Loss of methylation at P5 (P = 0.0126);
MVP		0.79
MPC		0.095
ClinPred		0.43	T
GERP RS		2.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.22
gMVP		0.52

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: rs890399221; hg19: chr20-61448429;