chr7-144453613-C-G

Position:

• chr7-144453613-C-G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1 PM2 PP3_Moderate PP5_Very_Strong

The NM_022445.4(TPK1):​c.664G>C​(p.Asp222His) variant causes a missense change. The variant allele was found at a frequency of 0.00000806 in 1,613,682 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: TPK1 NM_022445.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 5.12

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 Pathogenic. Variant got 14 ACMG points.

• PM1: In a chain Thiamin pyrophosphokinase 1 (size 242) in uniprot entity TPK1_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_022445.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.842
• PP5: Variant 7-144453613-C-G is Pathogenic according to our data. Variant chr7-144453613-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 419232.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TPK1	NM_022445.4	c.664G>C	p.Asp222His	missense_variant	9/9	ENST00000360057.7	NP_071890.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TPK1	ENST00000360057.7	c.664G>C	p.Asp222His	missense_variant	9/9	1	NM_022445.4	ENSP00000353165	P1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152066 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461616 Hom.: 0 Cov.: 30 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: 0.00000720

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152066 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74254

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: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Childhood encephalopathy due to thiamine pyrophosphokinase deficiency Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jan 17, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Breda Genetics srl	Mar 11, 2020	There is no information on frequency of this variant in gnomAD, 1000 Genomes or NHLI Exome Sequencing Project (ESP). The nucleotide position is conserved across 35 mammalian species (GERP RS: 4.61). This variant has been identified by Banka et al. (2014), in the homozygous state, in a patient with a non-episodic Leigh-like syndrome, with early developmental global developmental delay (PMID: 25458521). ClinVar contains an entry for this variant (Variation ID: 419232). -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 11, 2023

Published functional studies found p.(D222H) is associated with significantly reduced enzyme activity and protein expression (Banka et al., 2014; Huang et al., 2019); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 30483896, 25458521, 29269382) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.34
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.67	D;D;.
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.42
FATHMM_MKL	Uncertain	0.89	D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.84	D;D;D
MetaSVM	Uncertain	0.20	D
MutationAssessor	Pathogenic	3.1	M;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.1	D;D;D
REVEL	Pathogenic	0.84
Sift	Benign	0.042	D;D;T
Sift4G	Uncertain	0.049	D;D;T
Polyphen		1.0	D;P;D
Vest4		0.73
MutPred		0.48		Gain of disorder (P = 0.1459);.;.;
MVP		0.88
MPC		0.71
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.82
gMVP		0.74

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs368458768; hg19: chr7-144150706;