Genetic Variant ITPA:c.66+8G>T (chr20-3209625-G-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_033453.4(ITPA):c.66+8G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,656 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

ITPA
NM_033453.4 splice_region, intron

Scores

Splicing: ADA: 0.0002014

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.364

Publications

0 publications found

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 Gene-Disease associations (from GenCC):

genetic developmental and epileptic encephalopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 35
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
inosine triphosphatase deficiency
Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics

ITPA links:

ENSG00000289494 (HGNC:):

ENSG00000289494 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.65).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_033453.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
ITPA	NM_033453.4	MANE Select	c.66+8G>T	splice_region intron	N/A	NP_258412.1	A0A0S2Z3W7
ITPA	NM_001424408.1		c.66+8G>T	splice_region intron	N/A	NP_001411337.1
ITPA	NM_001424409.1		c.192+913G>T	intron	N/A	NP_001411338.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
ITPA	ENST00000380113.8	TSL:1 MANE Select	c.66+8G>T	splice_region intron	N/A	ENSP00000369456.3	Q9BY32-1
ITPA	ENST00000455664.6	TSL:1	c.15+59G>T	intron	N/A	ENSP00000413282.1	Q9BY32-2
ITPA	ENST00000399838.3	TSL:1	c.66+8G>T	splice_region intron	N/A	ENSP00000382732.3	Q9BY32-3

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152206

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461450

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727014

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53300

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111734

Other (OTH)

AF:

0.0000331

AC:

AN:

60386

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.512

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74352

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68044

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.592

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ClinVar

ClinVar submissions as Germline

Significance:Uncertain significance

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

Inosine triphosphatase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.65

CADD

Benign

(source)

DANN

Benign

0.87

PhyloP100

0.36

PromoterAI

0.14

Neutral

(source)

RBP_binding_hub_radar

0.85

RBP_regulation_power_radar

3.3

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00020

dbscSNV1_RF

Benign

0.080

SpliceAI score (max)

0.95

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.95

Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over