Genetic Variant ITPA:p.Ala2Glu (chr20-3209556-C-A) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2

The NM_033453.4(ITPA):c.5C>A(p.Ala2Glu) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,630 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: 0.0000055 ( 0 hom. )

Consequence

ITPA
NM_033453.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.99

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 4 ACMG points.

PM1

In a modified_residue N-acetylalanine (size 0) in uniprot entity ITPA_HUMAN

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.5C>A	p.Ala2Glu	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.5C>A	p.Ala2Glu	missense_variant	Exon 1 of 8	1	NM_033453.4	ENSP00000369456.3		Q9BY32-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251014

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135740

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000547

AC:

AN:

1461630

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727124

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000756

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000828

GnomAD4 genome

Cov.:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inosine triphosphatase deficiency

Uncertain:1

Jul 15, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with ITPA-related conditions. This variant is present in population databases (rs150370229, ExAC 0.02%). This sequence change replaces alanine with glutamic acid at codon 2 of the ITPA protein (p.Ala2Glu). The alanine residue is moderately conserved and there is a moderate physicochemical difference between alanine and glutamic acid. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.17

BayesDel_addAF

Uncertain

0.077

BayesDel_noAF

Uncertain

0.10

CADD

Pathogenic

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.48

T;.;.

Eigen

Uncertain

0.42

Eigen_PC

Uncertain

0.43

FATHMM_MKL

Uncertain

0.93

LIST_S2

Benign

0.50

T;T;T

M_CAP

Benign

0.012

MetaRNN

Uncertain

0.55

D;D;D

MetaSVM

Benign

-0.58

MutationAssessor

Benign

1.9

L;L;L

PrimateAI

Uncertain

0.65

PROVEAN

Benign

-1.2

N;N;N

REVEL

Benign

0.22

Sift

Uncertain

0.0020

D;T;D

Sift4G

Uncertain

0.039

D;D;T

Polyphen

1.0

D;.;.

Vest4

0.49

MutPred

0.19

Loss of MoRF binding (P = 0.0152);Loss of MoRF binding (P = 0.0152);Loss of MoRF binding (P = 0.0152);

MVP

0.74

MPC

1.1

ClinPred

0.96

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.82

gMVP

0.54

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

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