HPRT1

Chr X

hypoxanthine phosphoribosyltransferase 1

Also known as: HGPRT, HPRT

NCBI Gene: 3251ENSG00000165704UniProt: P00492

The protein encoded by this gene is a transferase, which catalyzes conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate via transfer of the 5-phosphoribosyl group from 5-phosphoribosyl 1-pyrophosphate. This enzyme plays a central role in the generation of purine nucleotides through the purine salvage pathway. Mutations in this gene result in Lesch-Nyhan syndrome or gout.[provided by RefSeq, Jun 2009]

GeneReviewsResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtLesch-Nyhan syndrome
UniProtHyperuricemia, HPRT-related

Clinical highlights

Gene-disease validity (ClinGen)
Lesch-Nyhan syndrome · XLDefinitivesufficient evidence for diagnostic panels
Interpreting a novel variant
Loss of function is the curated mechanism (Gene2Phenotype) and the gene is intolerant of it in the population — truncating, frameshift and canonical splice variants carry more prior weight here than missense.Curated gene-level mechanism — a prior for triage, not a per-variant call.
0
Active trials
54
Pubs (1 yr)
—
P/LP submissions
—
P/LP missense
0.34
LOEUF· LoF intol.
LOF
Mechanism· G2P
📖
GeneReview available — HPRT1
Authoritative clinical overview · Recommended first read
Open GeneReview ↗
Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
LoF intolerant — likely haploinsufficient
LoF Constraint?
0.34LOEUF
pLI 0.937
Z-score 2.75
OE 0.00 (0.00–0.34)
Highly constrained

Highly LoF-intolerant (top ~10% of genes)

Missense Constraint?
2.32Z-score
OE missense 0.26 (0.18–0.38)
20 obs / 77.4 exp
Mild constraint

Moderately missense-constrained (top ~2.5%)

Observed / Expected Ratios?
LoF OE?0.00 (0.00–0.34)
0≤0.351.4
Missense OE?0.26 (0.18–0.38)
0≤0.61.4
Synonymous OE?0.59
0≤1.21.6
LoF obs/exp: 0 / 8.8Missense obs/exp: 20 / 77.4Syn Z: 1.62

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

HPRT1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients