18-669151-C-CTG

Variant names:

• chr18-669151-C-CTG
• NM_001071.4:c.534_535insTG

Variant summary

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

The NM_001071.4(TYMS):​c.534_535insTG​(p.Met179fs) variant causes a frameshift, stop gained change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TYMS NM_001071.4 frameshift, stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 3.87

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]

ENOSF1 (HGNC:30365): (enolase superfamily member 1) This gene can encode a mitochondrial enzyme that is thought to convert L-fuconate to 2-keto-3-deoxy-L-fuconate. This locus was originally identified as the source of antisense RNAs of the adjacent thymidylate synthase gene. Splice variants at this locus may contain an alternate 3' exon that is complementary to the 3'UTR and terminal intron of the thymidylate synthase (TS) RNA and may downregulate TS expression. [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 18-669151-C-CTG is Pathogenic according to our data. Variant chr18-669151-C-CTG is described in ClinVar as [Pathogenic]. Clinvar id is 1693538.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TYMS	NM_001071.4	c.534_535insTG	p.Met179fs	frameshift_variant, stop_gained	Exon 4 of 7	ENST00000323274.15	NP_001062.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TYMS	ENST00000323274.15	c.534_535insTG	p.Met179fs	frameshift_variant, stop_gained	Exon 4 of 7	1	NM_001071.4	ENSP00000315644.10

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

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 frameshift variant of TYMS was identified in a 1-year old male with dyskeratosis congenita. It segregates with disease in his sister (aged 1), who also had dyskeratosis congenita. The following ACMG/AMP criteria were used: PVS1, PM2_supporting, PP3 -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr18-669151;