21-45504470-G-C

Variant names:

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_001379500.1(COL18A1):c.2782G>C(p.Gly928Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000894 in 1,607,028 control chromosomes in the GnomAD database, including 14 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Benign in ClinVar. Synonymous variant affecting the same amino acid position (i.e. G928G) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0047 ( 7 hom., cov: 33)

Exomes 𝑓: 0.00050 ( 7 hom. )

Consequence

COL18A1
NM_001379500.1 missense

Scores

Clinical Significance

Benign criteria provided, multiple submitters, no conflicts B:7

Conservation

PhyloP100: 4.95

Publications

3 publications found

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:

SLC19A1 (HGNC:10937): (solute carrier family 19 member 1) The membrane protein encoded by this gene is a transporter of folate and is involved in the regulation of intracellular concentrations of folate. Three transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Mar 2011]

SLC19A1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -20 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.008393288).

BP6

Variant 21-45504470-G-C is Benign according to our data. Variant chr21-45504470-G-C is described in ClinVar as Benign. ClinVar VariationId is 447121.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.0047 (710/151118) while in subpopulation AFR AF = 0.0164 (676/41148). AF 95% confidence interval is 0.0154. There are 7 homozygotes in GnomAd4. There are 331 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High Homozygotes in GnomAd4 at 7 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL18A1	NM_001379500.1 link	c.2782G>C	p.Gly928Arg	missense_variant	Exon 34 of 42	ENST00000651438.1	NP_001366429.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL18A1	ENST00000651438.1 link	c.2782G>C	p.Gly928Arg	missense_variant	Exon 34 of 42		NM_001379500.1	ENSP00000498485.1

Frequencies

GnomAD3 genomes

AF:

0.00470

AC:

709

AN:

151000

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0165

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00152

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:

0.0000295

Gnomad OTH

AF:

0.00435

GnomAD2 exomes

AF:

0.00115

AC:

274

AN:

237460

AF XY:

0.000885

show subpopulations

Gnomad AFR exome

AF:

0.0169

Gnomad AMR exome

AF:

0.00109

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000378

Gnomad OTH exome

AF:

0.000693

GnomAD4 exome

AF:

0.000499

AC:

726

AN:

1455910

Hom.:

Cov.:

AF XY:

0.000406

AC XY:

294

AN XY:

724276

show subpopulations

African (AFR)

AF:

0.0171

AC:

571

AN:

33378

American (AMR)

AF:

0.00123

AC:

AN:

44598

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26056

East Asian (EAS)

AF:

0.00

AC:

AN:

39664

South Asian (SAS)

AF:

0.0000349

AC:

AN:

86064

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51806

Middle Eastern (MID)

AF:

0.000564

AC:

AN:

5316

European-Non Finnish (NFE)

AF:

0.0000361

AC:

AN:

1108994

Other (OTH)

AF:

0.000899

AC:

AN:

60034

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.494

Heterozygous variant carriers

130

173

216

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00470

AC:

710

AN:

151118

Hom.:

Cov.:

AF XY:

0.00448

AC XY:

331

AN XY:

73854

show subpopulations

African (AFR)

AF:

0.0164

AC:

676

AN:

41148

American (AMR)

AF:

0.00152

AC:

AN:

15178

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5040

South Asian (SAS)

AF:

0.00

AC:

AN:

4780

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10510

Middle Eastern (MID)

AF:

0.00

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.0000295

AC:

AN:

67702

Other (OTH)

AF:

0.00430

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.494

Heterozygous variant carriers

122

152

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000196

Hom.:

Bravo

AF:

0.00536

ExAC

AF:

0.00147

AC:

172

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000119

ClinVar

Significance: Benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:3

Clinical Genetics, Academic Medical Center

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not specified

Benign:2

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

Dec 15, 2016

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

COL18A1-related disorder

Benign:1

Jul 17, 2019

PreventionGenetics, part of Exact Sciences

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).

Knobloch syndrome

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.31

BayesDel_addAF

Benign

-0.077

BayesDel_noAF

Uncertain

0.13

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.0

.;.;D;T

Eigen

Uncertain

0.49

Eigen_PC

Uncertain

0.28

FATHMM_MKL

Uncertain

0.77

LIST_S2

Benign

0.82

T;T;T;T

MetaRNN

Benign

0.0084

T;T;T;T

MetaSVM

Pathogenic

1.1

MutationAssessor

Benign

0.0

.;.;H;.

PhyloP100

4.9

PrimateAI

Uncertain

0.72

PROVEAN

Pathogenic

-5.0

D;D;D;D

REVEL

Uncertain

0.61

Sift

Uncertain

0.0030

D;D;D;D

Sift4G

Uncertain

0.0020

D;D;D;D

Vest4

0.75

ClinPred

0.056

GERP RS

4.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.24

gMVP

0.73

Mutation Taster

=84/16

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over