HGSNAT
Chr 8ARheparan-alpha-glucosaminide N-acetyltransferase
Also known as: HGNAT, MPS3C, RP73, TMEM76
This protein functions as a lysosomal acetyltransferase essential for heparan sulfate degradation. Mutations cause mucopolysaccharidosis type IIIC (Sanfilippo syndrome C), a lysosomal storage disorder resulting from impaired heparan sulfate breakdown, and retinitis pigmentosa 73, both inherited in an autosomal recessive pattern. The pathogenic mechanism involves deficient enzymatic activity leading to toxic accumulation of undegraded heparan sulfate in lysosomes.
Definitive — sufficient evidence for diagnostic panels
2 total gene-disease associations curated
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
500 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 | 25 | 0 | 14 | 0 | 39 |
Likely Pathogenic | 37 | 10 | 3 | 0 | 50 |
VUS | 1 | 113 | 36 | 7 | 157 |
Likely Benign | 0 | 2 | 137 | 93 | 232 |
Benign | 0 | 1 | 4 | 0 | 5 |
Conflicting | — | 3 | |||
| Total | 63 | 126 | 194 | 100 | 486 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
HGSNAT · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
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