21-45488416-A-G

Position:

chr21-45488416-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_ModeratePP5_Moderate

The NM_001379500.1(COL18A1):c.1897-2A>G variant causes a splice acceptor change. The variant allele was found at a frequency of 0.00000372 in 1,613,732 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

COL18A1
NM_001379500.1 splice_acceptor

Scores

Clinical Significance

Likely pathogenic criteria provided, single submitter P:2

Conservation

PhyloP100: 4.00

Variant links:

Genes affected

COL18A1 (HGNC:2195): (collagen type XVIII alpha 1 chain) This gene encodes the alpha chain of type XVIII collagen. This collagen is one of the multiplexins, extracellular matrix proteins that contain multiple triple-helix domains (collagenous domains) interrupted by non-collagenous domains. A long isoform of the protein has an N-terminal domain that is homologous to the extracellular part of frizzled receptors. Proteolytic processing at several endogenous cleavage sites in the C-terminal domain results in production of endostatin, a potent antiangiogenic protein that is able to inhibit angiogenesis and tumor growth. Mutations in this gene are associated with Knobloch syndrome. The main features of this syndrome involve retinal abnormalities, so type XVIII collagen may play an important role in retinal structure and in neural tube closure. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

COL18A1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.006467662 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PP5

Variant 21-45488416-A-G is Pathogenic according to our data. Variant chr21-45488416-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 438060.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr21-45488416-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	MANE	Protein
COL18A1	NM_001379500.1 linkuse as main transcript	c.1897-2A>G	splice_acceptor_variant	ENST00000651438.1	NP_001366429.1
COL18A1	NM_030582.4 linkuse as main transcript	c.2437-2A>G	splice_acceptor_variant		NP_085059.2
COL18A1	NM_130444.3 linkuse as main transcript	c.3142-2A>G	splice_acceptor_variant		NP_569711.2

Ensembl

Gene	Transcript	HGVSc	Effect	TSL	MANE	Protein	Appris	UniProt
COL18A1	ENST00000651438.1 linkuse as main transcript	c.1897-2A>G	splice_acceptor_variant		NM_001379500.1	ENSP00000498485		P39060-2
COL18A1	ENST00000355480.10 linkuse as main transcript	c.2437-2A>G	splice_acceptor_variant	1		ENSP00000347665		P39060-1
COL18A1	ENST00000359759.8 linkuse as main transcript	c.3142-2A>G	splice_acceptor_variant	5		ENSP00000352798	P1	P39060-3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD3 exomes

AF:

0.00000401

AC:

AN:

249218

Hom.:

AF XY:

0.00000739

AC XY:

AN XY:

135282

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461560

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727056

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74348

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.00000378

ExAC

AF:

0.00000827

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Oct 23, 2020

- -

Retinal dystrophy

Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

NIHR Bioresource Rare Diseases, University of Cambridge

Jan 01, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Benign

-0.28

CADD

Benign

DANN

Benign

0.93

Eigen

Pathogenic

0.69

Eigen_PC

Uncertain

0.41

FATHMM_MKL

Uncertain

0.91

MutationTaster

Benign

1.0

D;D;D

GERP RS

3.4

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.99

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over