rs1555773611

chr20-3213320-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Moderate BP6_Moderate

The NM_033453.4(ITPA):c.126G>A(p.Leu42=) variant causes a splice region, synonymous change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★). Synonymous variant affecting the same amino acid position (i.e. L42L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ITPA NM_033453.4 splice_region, synonymous
• Scores: Splicing: ADA: 0.1591
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 4.08

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]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.28).
• BP6: Variant 20-3213320-G-A is Benign according to our data. Variant chr20-3213320-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 533427.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ITPA	NM_033453.4	c.126G>A	p.Leu42=	splice_region_variant, synonymous_variant	3/8	ENST00000380113.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ITPA	ENST00000380113.8	c.126G>A	p.Leu42=	splice_region_variant, synonymous_variant	3/8	1	NM_033453.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inosine triphosphatase deficiency Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 13, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.28
Cadd	Benign	15
Dann	Benign	0.89
RBP_binding_hub_radar		0.97
RBP_regulation_power_radar		2.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.16
dbscSNV1_RF	Benign	0.28
SpliceAI score (max)		0.040		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: rs1555773611; hg19: chr20-3193966;