Is TTI1 p.His303Arg (c.908A>G) pathogenic?

TTI1 p.His303Arg (c.908A>G) is classified Uncertain significance in TTI1 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-09-02). AlphaMissense: ambiguous (0.4931); Very rare (popmax 0.00102%, nfe); Associated with Inborn genetic diseases.

What condition is associated with TTI1 p.His303Arg (c.908A>G)?

TTI1 p.His303Arg (c.908A>G) is associated with Inborn genetic diseases (ClinVar).

How common is TTI1 p.His303Arg (c.908A>G) in the general population?

TTI1 p.His303Arg (c.908A>G) is very rare (popmax 0.00102%, nfe) (gnomAD).

What do computational predictors say about TTI1 p.His303Arg (c.908A>G)?

AlphaMissense predicts ambiguous (score 0.4931) — an in-silico prediction, not a clinical call.

TTI1 p.His303Arg

c.908A>G · VCV3463544

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.4931 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00102%, nfe)

Conditions

Inborn genetic diseases

Computational evidence

Protein change
AlphaMissense	0.4931	ambiguous
REVEL	0.556	indeterminate
SaProt	LLR -11.78	damaging
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 7.9	GERP 2.5, phastCons 1
Regional constraint	o/e 0.91	unconstrained · MANE · 30 kb · p 0.00063 · regional, not allelic
Overall
CADD	24.7	PHRED · no single calibrated threshold — expert panels disagree

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00102% European (non-Finnish) · 12/1,180,048 alleles

Filtering AF 0.000542% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000428%

Overall 0.000743% 12/1,614,070 alleles · very rare exomes 11/1,461,874 · genomes 1/152,196 · joint denominator

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: TTI1
Protein: p.His303Arg
Coding: c.908A>G
MANE Select: NM_001303457
Type: single nucleotide variant
Location: chr20:38012909 (GRCh38)
Gene constraint: LOEUF 0.78 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 81.38 · 3 PDB
Residue 303: a UniProt-annotated variant site (in nedmim; likely pathogenic)

Full TTI1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Inborn genetic diseases — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

TTI1 p.His303Tyr Uncertain significance ★ ⚠ same residue
TTI1 p.Ala806Thr Uncertain significance ★★ ⚠ same condition
TTI1 p.Arg519Gln Uncertain significance ★★ ⚠ same condition
TTI1 p.Arg724Gly Uncertain significance ★★ ⚠ same condition
TTI1 p.Arg869Cys Uncertain significance ★★ same condition
TTI1 p.Cys86Tyr Uncertain significance ★★ ⚠ same condition
TTI1 p.His229Tyr Uncertain significance ★★ ⚠ same condition
TTI1 p.His513Tyr 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/tti1-p-his303arg (accessed [today's date]).

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