7-144453562-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_022445.4(TPK1):c.715A>G(p.Met239Val) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,206 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TPK1 NM_022445.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.26

Genes affected

TPK1 (HGNC:17358): (thiamin pyrophosphokinase 1) The protein encoded by this gene functions as a homodimer and catalyzes the conversion of thiamine to thiamine pyrophosphate, a cofactor for some enzymes of the glycolytic and energy production pathways. Defects in this gene are a cause of thiamine metabolism dysfunction syndrome-5. [provided by RefSeq, Apr 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a chain Thiamin pyrophosphokinase 1 (size 242) in uniprot entity TPK1_HUMAN there are 17 pathogenic changes around while only 1 benign (94%) in NM_022445.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TPK1	NM_022445.4	c.715A>G	p.Met239Val	missense_variant	9/9	ENST00000360057.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TPK1	ENST00000360057.7	c.715A>G	p.Met239Val	missense_variant	9/9	1	NM_022445.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251338 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135826

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461206 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726944

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Childhood encephalopathy due to thiamine pyrophosphokinase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 25, 2022

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 239 of the TPK1 protein (p.Met239Val). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with TPK1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Benign	0.17	T;T;.
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.91	D
M_CAP	Uncertain	0.13	D
MetaRNN	Uncertain	0.72	D;D;D
MetaSVM	Uncertain	-0.065	T
MutationAssessor	Benign	1.7	L;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-3.0	D;D;N
REVEL	Uncertain	0.45
Sift	Benign	0.030	D;D;T
Sift4G	Benign	0.15	T;T;T
Polyphen		0.99	D;P;P
Vest4		0.64
MutPred		0.48		Loss of ubiquitination at K242 (P = 0.0727);.;.;
MVP		0.65
MPC		0.48
ClinPred		0.95	D
GERP RS		5.8
Varity_R		0.76
gMVP		0.77

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: rs1404980051; hg19: chr7-144150655;