Is CYBB p.Thr99= (c.297C>A) pathogenic?

CYBB p.Thr99= (c.297C>A) is classified Likely benign in CYBB (ClinVar, Single submitter, 1 submitter; last evaluated 2026-01-15). Very rare (popmax 0.00653%, amr); Associated with granulomatous disease, chronic, X-linked.

What condition is associated with CYBB p.Thr99= (c.297C>A)?

CYBB p.Thr99= (c.297C>A) is associated with granulomatous disease, chronic, X-linked (ClinVar).

How common is CYBB p.Thr99= (c.297C>A) in the general population?

CYBB p.Thr99= (c.297C>A) is very rare (popmax 0.00653%, amr) (gnomAD).

How is Chronic granulomatous disease inherited?

Typically Autosomal recessive, X-linked recessive (Orphanet). A genetic counselor can assess individual risk for a family.

CYBB p.Thr99=

c.297C>A · rs1556467101 · VCV756771

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00653%, amr)

Conditions

granulomatous disease, chronic, X-linked

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 -0.37	GERP -0.046, phastCons 0.09
Overall
CADD	5.417	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00653% Admixed American · 3/45,938 alleles

Filtering AF 0.00173% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00088%

Overall 0.000639% 7/1,094,721 alleles · very rare

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.00653%	15,313
Remaining individualsnot grpmax-eligible	0.00211%	47,478
European (non-Finnish)	0.000336%	297,538

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: CYBB
Protein: p.Thr99=
Coding: c.297C>A
MANE Select: NM_000397
dbSNP: rs1556467101
Type: single nucleotide variant
Location: chrX:37792019 (GRCh38)
Structure: AlphaFold pLDDT 90.29 · 6 PDB
Residue 99: an α-helix; the ferric oxidoreductase domain

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

Disease context

granulomatous disease, chronic, X-linked — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Chronic granulomatous disease (Orphanet):

Inheritance: Autosomal recessive, X-linked recessive
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: 1-9 / 1 000 000 (Worldwide)

Similar variants

CYBB c.1315-2A>G Pathogenic/Likely pathogenic ★★ same condition
CYBB c.141+1G>T Pathogenic ★★ same condition
CYBB c.252+5G>A Pathogenic ★★ same condition
CYBB c.483+1G>A Pathogenic ★★ same condition
CYBB c.483+1G>T Pathogenic ★★ same condition
CYBB c.483+3A>T Likely pathogenic ★★ same condition
CYBB p.Ala156Thr Pathogenic/Likely pathogenic ★★ ⚠ same condition
CYBB p.Ala57Glu Pathogenic ★★ 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/cybb-p-thr99 (accessed [today's date]).

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