dbSNP rs1407446171: ITPA:p.Gly123SerfsTer104 (chr20-3218578-A-ACTCAGCAC) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_033453.4(ITPA):c.359_366dupTCAGCACC(p.Gly123SerfsTer104) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000044 in 1,613,816 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000044 ( 0 hom. )

Consequence

ITPA
NM_033453.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 0.588

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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 20-3218578-A-ACTCAGCAC is Pathogenic according to our data. Variant chr20-3218578-A-ACTCAGCAC is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 218091.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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	HGVSp	Effect	Exon Rank	Protein	UniProt
ITPA	NM_033453.4	MANE Select	c.359_366dupTCAGCACC	p.Gly123SerfsTer104	frameshift	Exon 6 of 8	NP_258412.1	A0A0S2Z3W7
ITPA	NM_001424408.1		c.359_366dupTCAGCACC	p.Gly123SerfsTer54	frameshift	Exon 6 of 9	NP_001411337.1
ITPA	NM_001424409.1		c.485_492dupTCAGCACC	p.Gly165SerfsTer104	frameshift	Exon 7 of 9	NP_001411338.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
ITPA	ENST00000380113.8	TSL:1 MANE Select	c.359_366dupTCAGCACC	p.Gly123SerfsTer104	frameshift	Exon 6 of 8	ENSP00000369456.3	Q9BY32-1
ITPA	ENST00000455664.6	TSL:1	c.308_315dupTCAGCACC	p.Gly106SerfsTer104	frameshift	Exon 6 of 8	ENSP00000413282.1	Q9BY32-2
ITPA	ENST00000399838.3	TSL:1	c.236_243dupTCAGCACC	p.Gly82SerfsTer104	frameshift	Exon 4 of 6	ENSP00000382732.3	Q9BY32-3

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152082

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:

0.000189

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000320

AC:

AN:

250252

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.0000994

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000355

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000438

AC:

AN:

1461616

Hom.:

Cov.:

AF XY:

0.0000358

AC XY:

AN XY:

727114

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000447

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000765

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000188

AC:

AN:

53170

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000531

AC:

AN:

1111990

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.456

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:

0.0000460

AC:

AN:

152200

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74420

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41524

American (AMR)

AF:

0.00

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.000189

AC:

AN:

10588

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000735

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

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:

0.000169

Hom.:

Bravo

AF:

0.0000264

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Developmental and epileptic encephalopathy, 35 (6)

not provided (3)

Hypodontia (1)

Inosine triphosphatase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.59

Mutation Taster

=4/196

disease causing (ClinVar)

(source)

Splicing

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