ITPA
Chr 20ARinosine triphosphatase
Also known as: C20orf37, DEE35, HLC14-06-P, ITPase, My049, NTPase, dJ794I6.3
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]
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
This gene — mechanism propensity
The highest-scoring mechanism for this gene is dominant-negative.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
361 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 20 | 0 | 4 | 0 | 24 |
Likely Pathogenic | 17 | 2 | 0 | 0 | 19 |
VUS | 4 | 102 | 20 | 1 | 127 |
Likely Benign | 1 | 33 | 67 | 45 | 146 |
Benign | 0 | 5 | 22 | 2 | 29 |
Conflicting | — | 5 | |||
| Total | 42 | 142 | 113 | 48 | 350 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →30 pathogenic / likely-pathogenic (of 49) ClinVar copy-number / structural variants overlap ITPA — these span large chromosomal regions, not the gene specifically, and are excluded from the counts above. Explore in CNV tools →
Protein Context — Lollipop Plot
ITPA · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools