18-662209-C-T

Variant names:

• chr18-662209-C-T
• rs2046518776
• NM_001071.4:c.343C>T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001071.4(TYMS):​c.343C>T​(p.Arg115*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000616 in 1,461,636 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: TYMS NM_001071.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 3.79

Genes affected

TYMS (HGNC:12441): (thymidylate synthetase) Thymidylate synthase catalyzes the methylation of deoxyuridylate to deoxythymidylate using, 10-methylenetetrahydrofolate (methylene-THF) as a cofactor. This function maintains the dTMP (thymidine-5-prime monophosphate) pool critical for DNA replication and repair. The enzyme has been of interest as a target for cancer chemotherapeutic agents. It is considered to be the primary site of action for 5-fluorouracil, 5-fluoro-2-prime-deoxyuridine, and some folate analogs. Expression of this gene and that of a naturally occurring antisense transcript, mitochondrial enolase superfamily member 1 (GeneID:55556), vary inversely when cell-growth progresses from late-log to plateau phase. Polymorphisms in this gene may be associated with etiology of neoplasia, including breast cancer, and response to chemotherapy. [provided by RefSeq, Aug 2017]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-662209-C-T is Pathogenic according to our data. Variant chr18-662209-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 1693535.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr18-662209-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TYMS	NM_001071.4	c.343C>T	p.Arg115*	stop_gained	Exon 3 of 7	ENST00000323274.15	NP_001062.1
TYMS	NM_001354867.2	c.343C>T	p.Arg115*	stop_gained	Exon 3 of 6		NP_001341796.1
TYMS	NM_001354868.2	c.205+4262C>T		intron_variant	Intron 1 of 4		NP_001341797.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TYMS	ENST00000323274.15	c.343C>T	p.Arg115*	stop_gained	Exon 3 of 7	1	NM_001071.4	ENSP00000315644.10
TYMS	ENST00000323224.7	c.343C>T	p.Arg115*	stop_gained	Exon 3 of 6	1		ENSP00000314727.7
TYMS	ENST00000323250.9	c.205+4262C>T		intron_variant	Intron 1 of 4	1		ENSP00000314902.5
TYMS	ENST00000579128.1	n.421C>T		non_coding_transcript_exon_variant	Exon 3 of 4	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461636 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727130

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000370 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Dyskeratosis congenita, digenic Pathogenic:1

Sep 22, 2022

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Dyskeratosis congenita Pathogenic:1

Jun 22, 2022

Bone Marrow Failure laboratory, Queen Mary University London

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

This heterozygous nonsense variant of TYMS was identified in a 3-year old male with dyskeratosis congenita. The following ACMG/AMP criteria were used: PVS1, PM2_supporting, PP3 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Pathogenic	0.74
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.87	D
Vest4		0.90
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs2046518776; hg19: chr18-662209; COSMIC: COSV60074401; COSMIC: COSV60074401;