rs774337224

Positions:

chr21-45505206-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP4

The NM_001379500.1(COL18A1):c.2941G>A(p.Glu981Lys) variant causes a missense change. The variant allele was found at a frequency of 0.0000524 in 1,603,672 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. E981G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000050 ( 0 hom. )

Consequence

COL18A1
NM_001379500.1 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 4.88

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 made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.28057846).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL18A1	NM_001379500.1 linkuse as main transcript	c.2941G>A	p.Glu981Lys	missense_variant	35/42	ENST00000651438.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL18A1	ENST00000651438.1 linkuse as main transcript	c.2941G>A	p.Glu981Lys	missense_variant	35/42		NM_001379500.1		P39060-2

Frequencies

GnomAD3 genomes

AF:

0.0000724

AC:

AN:

151890

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000170

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.0000542

AC:

AN:

221364

Hom.:

AF XY:

0.0000655

AC XY:

AN XY:

122060

show subpopulations

Gnomad AFR exome

AF:

0.0000824

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000310

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000205

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000503

AC:

AN:

1451664

Hom.:

Cov.:

AF XY:

0.0000513

AC XY:

AN XY:

721578

show subpopulations

Gnomad4 AFR exome

AF:

0.000390

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000762

Gnomad4 SAS exome

AF:

0.000270

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000262

Gnomad4 OTH exome

AF:

0.0000668

GnomAD4 genome

AF:

0.0000724

AC:

AN:

152008

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74320

show subpopulations

Gnomad4 AFR

AF:

0.000169

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000194

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000474

Alfa

AF:

0.000130

Hom.:

Bravo

AF:

0.0000793

ExAC

AF:

0.0000509

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jan 13, 2023	In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Nov 25, 2023	This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 978 of the COL18A1 protein (p.Glu978Lys). This variant is present in population databases (rs774337224, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with COL18A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 445666). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	Jun 02, 2017	- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.39

BayesDel_addAF

Benign

-0.078

BayesDel_noAF

Uncertain

-0.050

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Benign

0.17

Eigen_PC

Uncertain

0.23

FATHMM_MKL

Uncertain

0.88

LIST_S2

Uncertain

0.90

D;D;D;D

M_CAP

Pathogenic

0.42

MetaRNN

Benign

0.28

T;T;T;T

MetaSVM

Uncertain

0.25

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.79

PROVEAN

Uncertain

-2.6

D;D;D;D

REVEL

Uncertain

0.49

Sift

Benign

0.18

T;T;T;T

Sift4G

Benign

0.16

T;T;T;T

Polyphen

0.99

D;D;D;.

Vest4

0.51

MVP

0.92

MPC

0.43

ClinPred

0.34

GERP RS

4.3

Varity_R

0.28

gMVP

0.13

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

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