Is HPD p.Arg300= (c.898C>A) pathogenic?

HPD p.Arg300= (c.898C>A) is classified Likely benign in HPD (ClinVar, Single submitter, 1 submitter; last evaluated 2026-01-24). Ultra-rare (popmax 0.0822%, mid); Associated with hawkinsinuria.

What condition is associated with HPD p.Arg300= (c.898C>A)?

HPD p.Arg300= (c.898C>A) is associated with hawkinsinuria, tyrosinemia type III (ClinVar).

How common is HPD p.Arg300= (c.898C>A) in the general population?

HPD p.Arg300= (c.898C>A) is ultra-rare (popmax 0.0822%, mid) (gnomAD).

How is Hawkinsinuria inherited?

Typically Autosomal dominant (Orphanet). A genetic counselor can assess individual risk for a family.

HPD p.Arg300=

c.898C>A · rs149281612 · VCV712611

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0822%, mid)

Conditions

hawkinsinuria

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.5	GERP 1.5, phastCons 1
Overall
CADD	8.86	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0822% Middle Eastern · 5/6,084 alleles

Filtering AF 0.0615% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0557%

Overall 0.00465% 75/1,613,890 alleles · ultra-rare exomes 38/1,461,820 · genomes 37/152,070 · joint denominator

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0822%	1,217
African / African-American	0.0775%	1,291
Remaining individualsnot grpmax-eligible	0.0048%	20,827
European (non-Finnish)	0.000763%	131,109

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: HPD
Protein: p.Arg300=
Coding: c.898C>A
MANE Select: NM_002150
dbSNP: rs149281612
Type: single nucleotide variant
Location: chr12:121843766 (GRCh38)
Gene constraint: LOEUF 0.845 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.00 · 4 PDB
Residue 300: a UniProt-annotated variant site (in tyrsn3; likely pathogenic); the voc 2 domain; an α-helix

Full HPD gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hawkinsinuria — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: tyrosinemia type III

For Hawkinsinuria (Orphanet):

Inheritance: Autosomal dominant
Onset: Infancy, Neonatal
Prevalence: <1 / 1 000 000 (Worldwide)

Similar variants

HPD p.Arg300Trp Uncertain significance ★★ ⚠ same residue
HPD p.Arg300Gln Uncertain significance ★ ⚠ same residue
HPD p.Arg225Ter Pathogenic/Likely pathogenic ★★ same condition
HPD p.Gln205Ter Pathogenic/Likely pathogenic ★★ same condition
HPD p.Tyr160Cys Likely pathogenic ★★ same condition
HPD p.Ala230Thr Uncertain significance ★★ ⚠ same condition
HPD p.Arg111Trp Uncertain significance ★★ ⚠ same condition
HPD p.Arg119Gln Uncertain significance ★★ ⚠ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/hpd-p-arg300 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown