Genetic Variant COL9A3:c.477+33G>C (chr20-62822197-G-C) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_001853.4(COL9A3):c.477+33G>C variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 152,002 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Consequence

COL9A3
NM_001853.4 intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -1.12

Publications

12 publications found

Variant links:

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]

COL9A3 Gene-Disease associations (from GenCC):

epiphyseal dysplasia, multiple, 3
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, Illumina, G2P, Labcorp Genetics (formerly Invitae)
Stickler syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Ambry Genetics, Genomics England PanelApp, ClinGen
Stickler syndrome, type 6
Inheritance: AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
multiple epiphyseal dysplasia due to collagen 9 anomaly
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive Stickler syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

COL9A3 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.85).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL9A3	NM_001853.4 link	c.477+33G>C		intron_variant	Intron 9 of 31	ENST00000649368.1	NP_001844.3

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein
COL9A3	ENST00000649368.1 link	c.477+33G>C	intron_variant	Intron 9 of 31		NM_001853.4	ENSP00000496793.1
COL9A3	ENST00000452372.2 link	c.366+33G>C	intron_variant	Intron 8 of 11	5		ENSP00000394280.1
COL9A3	ENST00000477612.5 link	n.473+33G>C	intron_variant	Intron 9 of 11	3
COL9A3	ENST00000489045.5 link	n.523+33G>C	intron_variant	Intron 8 of 13	5

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152002

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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

GnomAD2 exomes

AF:

0.00000403

AC:

AN:

248048

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000622

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

Cov.:

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152002

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74234

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000242

AC:

AN:

41384

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67976

Other (OTH)

AF:

0.00

AC:

AN:

2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

9821

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.85

CADD

Benign

0.087

(source)

DANN

Benign

0.69

PhyloP100

-1.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over