21-45493584-C-T

Variant names:

• chr21-45493584-C-T
• rs756318040
• ENST00000417954:c.*2751G>A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The ENST00000417954(SLC19A1):​c.*2751G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000904 in 1,549,260 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 Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000079 (0 hom.)
• Consequence: SLC19A1 ENST00000417954 3_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:2
• Conservation: PhyloP100: -3.32

Genes affected

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]

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]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.85).
• BP6: Variant 21-45493584-C-T is Benign according to our data. Variant chr21-45493584-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 1611559.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL18A1	NM_001379500.1	c.2352+9C>T		intron_variant	Intron 26 of 41	ENST00000651438.1	NP_001366429.1
COL18A1	NM_130444.3	c.3597+9C>T		intron_variant	Intron 25 of 40		NP_569711.2
COL18A1	NM_030582.4	c.2892+9C>T		intron_variant	Intron 25 of 40		NP_085059.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL18A1	ENST00000651438.1	c.2352+9C>T		intron_variant	Intron 26 of 41		NM_001379500.1	ENSP00000498485.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152212 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.00

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: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000131 AC: 2 AN: 152584 Hom.: 0 AF XY: 0.0000246 AC XY: 2 AN XY: 81416

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: 0.0000439

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000171

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000787 AC: 11 AN: 1397048 Hom.: 0 Cov.: 32 AF XY: 0.00000725 AC XY: 5 AN XY: 689314

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000559

Gnomad4 SAS exome AF: 0.0000252

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000557

Gnomad4 OTH exome AF: 0.0000173

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152212 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 74364

Gnomad4 AFR AF: 0.00

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: 0.0000441

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Benign:1

Feb 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

COL18A1-related disorder Benign:1

Jul 11, 2019

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

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

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.85
CADD	Benign	0.69
DANN	Benign	0.80
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

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: rs756318040; hg19: chr21-46913498;