Genetic Variant ITPA:p.Leu20Met (chr20-3209609-C-A) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001324236.2(ITPA):c.-283C>A variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000254 in 1,613,858 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

ITPA
NM_001324236.2 5_prime_UTR_premature_start_codon_gain

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.32

Variant links:

Genes affected

ITPA (HGNC:6176): (inosine triphosphatase) This gene encodes an inosine triphosphate pyrophosphohydrolase. The encoded protein hydrolyzes inosine triphosphate and deoxyinosine triphosphate to the monophosphate nucleotide and diphosphate. This protein, which is a member of the HAM1 NTPase protein family, is found in the cytoplasm and acts as a homodimer. Defects in the encoded protein can result in inosine triphosphate pyrophosphorylase deficiency which causes an accumulation of ITP in red blood cells. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jun 2012]

ITPA links:

ENSG00000289494 (HGNC:):

ENSG00000289494 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ITPA	NM_033453.4 link	c.58C>A	p.Leu20Met	missense_variant	Exon 1 of 8	ENST00000380113.8	NP_258412.1	Q9BY32-1A0A0S2Z3W7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ITPA	ENST00000380113.8 link	c.58C>A	p.Leu20Met	missense_variant	Exon 1 of 8	1	NM_033453.4	ENSP00000369456.3		Q9BY32-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

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

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

250726

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135598

show subpopulations

Gnomad AFR exome

AF:

0.0000617

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:

0.0000353

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000274

AC:

AN:

1461728

Hom.:

Cov.:

AF XY:

0.0000289

AC XY:

AN XY:

727158

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

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:

0.0000342

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152130

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74316

show subpopulations

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

Alfa

AF:

0.0000625

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Nov 09, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.58C>A (p.L20M) alteration is located in exon 1 (coding exon 1) of the ITPA gene. This alteration results from a C to A substitution at nucleotide position 58, causing the leucine (L) at amino acid position 20 to be replaced by a methionine (M). 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

Benign

0.24

BayesDel_addAF

Benign

-0.0079

BayesDel_noAF

Uncertain

-0.070

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.76

D;.

Eigen

Pathogenic

0.74

Eigen_PC

Uncertain

0.63

FATHMM_MKL

Uncertain

0.83

LIST_S2

Pathogenic

0.98

D;T

M_CAP

Benign

0.073

MetaRNN

Uncertain

0.58

D;D

MetaSVM

Uncertain

0.28

MutationAssessor

Pathogenic

4.0

H;H

PrimateAI

Uncertain

0.72

PROVEAN

Benign

-1.9

N;N

REVEL

Uncertain

0.47

Sift

Uncertain

0.0010

D;D

Sift4G

Uncertain

0.0030

D;D

Polyphen

1.0

D;.

Vest4

0.47

MutPred

0.70

Loss of methylation at K19 (P = 0.0367);Loss of methylation at K19 (P = 0.0367);

MVP

0.66

MPC

0.97

ClinPred

0.99

GERP RS

4.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.94

gMVP

0.41

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over