Is HAP1 p.Cys9Ser (c.26G>C) pathogenic?

HAP1 p.Cys9Ser (c.26G>C) is classified Uncertain significance in HAP1 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-07-02). AlphaMissense: likely benign (0.078); Very rare (popmax 0.00459%, eas).

How common is HAP1 p.Cys9Ser (c.26G>C) in the general population?

HAP1 p.Cys9Ser (c.26G>C) is very rare (popmax 0.00459%, eas) (gnomAD).

What do computational predictors say about HAP1 p.Cys9Ser (c.26G>C)?

AlphaMissense predicts likely benign (score 0.078) — an in-silico prediction, not a clinical call.

HAP1 p.Cys9Ser

c.26G>C · VCV3523903

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.078 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00459%, eas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.078	likely benign
REVEL	0.005	strongly benign-leaning
SaProt	LLR -4.79	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -1.3	GERP 0.27
Regional constraint	o/e 1.05	unconstrained · MANE · 9,930 bp · p 0.16 · regional, not allelic
Overall
CADD	0.769	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00459% East Asian · 2/43,564 alleles

Filtering AF 0.000761% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000285%

Overall 0.000256% 4/1,562,630 alleles · very rare exomes 4/1,410,342 · genomes 0/152,288 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00459%	21,782
Remaining individualsnot grpmax-eligible	0.00331%	30,231

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: HAP1
Protein: p.Cys9Ser
Coding: c.26G>C
MANE Select: NM_177977
Type: single nucleotide variant
Location: chr17:41734609 (GRCh38)
Gene constraint: LOEUF 1.31 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 64.28
Residue 9: the 'disordered' region

Full HAP1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

HAP1 p.Cys9Tyr Uncertain significance ★ ⚠ same residue
HAP1 p.Cys9Gly Likely benign ★ same residue
HAP1 p.Arg106Pro Uncertain significance ★★ ⚠ same type
HAP1 p.Cys25Tyr Benign ★★ same type
HAP1 p.Gly604Arg Benign ★★ same type
HAP1 p.Ile496Val Benign ★★ same type
HAP1 p.Leu348= Benign ★★ same type
HAP1 p.Ser616Ter Benign ★★ same type

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/hap1-p-cys9ser (accessed [today's date]).

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