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Q687H

Category 3/4 — Most DruggableConflictingLumenal · predictedσ-1 candidateEditorial
GlutamineHistidine at position 687 · C-terminal lumenal domain (653-869) · WFS1 (Wolframin)

Glutamine → Histidine at position 687 in wolframin's C-terminal lumenal domain. ClinVar Conflicting classifications. AlphaMissense 0.996 (near-maximum), DynaMut2 ΔΔG -0.19 kcal/mol (mild destabilising). Strong AM signal in the dense 684-688 cluster.

Interactive 3D Structure

Wild-type reference
Wild-type Q687 — hydrogen bond to C690
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DynaMut2 mutant · Q687H
Mutant H687 — hydrogen bond to L833 lost (3 contacts lost)
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Bond changes · DynaMut2 interaction analysis

3 lost3 gained9 preserved
Interaction typeWild-type partnerMutant partnerStatus
Hydrogen bondM683M683Preserved
Hydrogen bondA684A684Preserved
Hydrogen bondC690Lost
Hydrogen bondS691S691Preserved
Hydrogen bondL833L833Preserved
Polar contactM683M683Preserved
Polar contactA684A684Preserved
Polar contactR685Gained
Polar contactC690C690Preserved
Polar contactS691S691Preserved
Polar contactL833L833Preserved
Van der WaalsR685Gained
Van der WaalsL689Lost
Van der WaalsL833Gained
HydrophobicM683Lost

Lost / gained / preserved interatomic contacts at the variant residue, from the DynaMut2 (Arpeggio) interaction analysis of the wild-type and energy-minimized mutant structures.

Computational Predictions

DynaMut2 ΔΔG
-0.19kcal/mol
Destabilising — mild
AlphaMissense
0.996
LPath
AlphaFold pLDDT
89
model confidence
Schema
Cat 3/4
Category 3/4 — Most Druggable

Clinical Evidence

ClinVar classificationConflicting classifications of pathogenicity
Review statuscriteria provided, conflicting classifications
Associated conditionsAutosomal dominant nonsyndromic hearing loss 6 (DFNA6)
InheritanceConflicting classifications. AD-leaning given DFNA6 association.
Population frequency (gnomAD v4)Ultra-rare · AF 0.00037%
cDNA changec.2061G>C
ClinVar accessionVCV000427196
Last evaluated2025/08/17 00:00

Observed at very low frequency in gnomAD.

Structural Context

Position 687 sits in the dense 684-688 cluster discussed in the A684T, A684V, R685P, I688F Atlas cards. The AlphaFold model places Q687 within 5 Å of THR686 (2.5 Å), ILE688 (2.5 Å — partner of I688F), LEU833 (3.6 Å — long-range), ALA684 (3.8 Å — partner of A684T, A684V), and MET683 (3.9 Å).

The wild-type glutamine's amide likely H-bonds with the surrounding polar residues in this cluster. Replacing Q687 with histidine introduces an aromatic imidazole with pH-dependent charge. The H-bond geometry changes substantially.

The |ΔΔG| of 0.19 reflects fold accommodation. AlphaMissense's 0.996 (near-maximum) is strong pathogenic signal. ClinVar conflicting classifications suggest context-dependent functional consequence.

Amino-acid chemistry
Glutamine (Q) → Histidine (H) — polar amide replaced by aromatic titratable basic residue. Aromatic character introduced; pH-dependent charge added.
Position in the protein
C-terminal lumenal domain · position 687 in the ER lumen (pLDDT 89).

Druggability Assessment

Category 3/4 — Most Druggable. |ΔΔG| = 0.19 — fold survives. AlphaMissense 0.996 (near-maximum) confirms severe pathogenic mechanism.

Mechanism is amide-to-aromatic substitution disrupting the 684-688 cluster H-bond network. Therapeutic strategy: same cluster target as A684T, A684V, R685P, I688F.

Why this matters

Q687H is the FIFTH Atlas variant in the 684-688 microregion. This is one of the densest multi-variant target clusters in the entire Atlas. Drug discovery here rescues five known pathogenic variants simultaneously.
Therapeutic Strategy Handoff · prediction

Feed this card to Wolfram Intelligence

Download the Q687H PDF below and upload it to Wolfram Intelligence to generate therapeutic-strategy proposals — guanidinium mimetics, sigma-1 agonist docking, NAC thiol-capping. NAC is already on the bench-testing list.

Download Q687H PDF card ↓Strategies are AI-generated predictions, not validated therapeutics.

UniProt Domain Annotation

Chain1890 · Wolframin
Topological domain653869 · Lumenal