17-78185132-C-G

Variant names:

• chr17-78185132-C-G
• rs753556251
• NM_003258.5:c.132G>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_003258.5(TK1):​c.132G>C​(p.Gln44His) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,652 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: TK1 NM_003258.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.83

Genes affected

TK1 (HGNC:11830): (thymidine kinase 1) The protein encoded by this gene is a cytosolic enzyme that catalyzes the addition of a gamma-phosphate group to thymidine. This creates dTMP and is the first step in the biosynthesis of dTTP, which is one component required for DNA replication. The encoded protein, whose levels fluctuate depending on the cell cycle stage, can act as a low activity dimer or a high activity tetramer. High levels of this protein have been used as a biomarker for diagnosing and categorizing many types of cancers. [provided by RefSeq, Oct 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.819

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TK1	NM_003258.5	c.132G>C	p.Gln44His	missense_variant	Exon 3 of 7	ENST00000301634.12	NP_003249.3
TK1	NM_001363848.1	c.132G>C	p.Gln44His	missense_variant	Exon 3 of 6		NP_001350777.1
TK1	NM_001346663.2	c.132G>C	p.Gln44His	missense_variant	Exon 3 of 7		NP_001333592.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TK1	ENST00000301634.12	c.132G>C	p.Gln44His	missense_variant	Exon 3 of 7	1	NM_003258.5	ENSP00000301634.6

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461652 Hom.: 0 Cov.: 31 AF XY: 0.00000825 AC XY: 6 AN XY: 727106

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: 0.00000630

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jul 20, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.132G>C (p.Q44H) alteration is located in exon 3 (coding exon 3) of the TK1 gene. This alteration results from a G to C substitution at nucleotide position 132, causing the glutamine (Q) at amino acid position 44 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D;.;.;T;T
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	D;D;D;D;D
M_CAP	Benign	0.048	D
MetaRNN	Pathogenic	0.82	D;D;D;D;D
MetaSVM	Uncertain	0.17	D
MutationAssessor	Uncertain	2.5	M;.;.;.;.
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-3.9	D;.;.;.;.
REVEL	Pathogenic	0.67
Sift	Uncertain	0.0040	D;.;.;.;.
Sift4G	Uncertain	0.018	D;D;D;D;.
Polyphen		1.0	D;.;.;.;.
Vest4		0.84
MutPred		0.56		Loss of catalytic residue at Q44 (P = 0.029);Loss of catalytic residue at Q44 (P = 0.029);Loss of catalytic residue at Q44 (P = 0.029);Loss of catalytic residue at Q44 (P = 0.029);Loss of catalytic residue at Q44 (P = 0.029);
MVP		0.72
MPC		0.66
ClinPred		0.98	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.79
gMVP		0.83

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs753556251; hg19: chr17-76181213;