Is GNB4 p.Phe278= (c.834C>T) pathogenic?

GNB4 p.Phe278= (c.834C>T) is classified Likely benign in GNB4 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-05-27). Ultra-rare (popmax 0.011%, sas); Associated with Charcot-Marie-Tooth disease dominant intermediate F.

What condition is associated with GNB4 p.Phe278= (c.834C>T)?

GNB4 p.Phe278= (c.834C>T) is associated with Charcot-Marie-Tooth disease dominant intermediate F (ClinVar).

How common is GNB4 p.Phe278= (c.834C>T) in the general population?

GNB4 p.Phe278= (c.834C>T) is ultra-rare (popmax 0.011%, sas) (gnomAD).

GNB4 p.Phe278=

Q: How is Autosomal dominant intermediate Charcot-Marie-Tooth disease type F inherited?

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

c.834C>T · rs540700486 · VCV2178653

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.011%, sas)

Conditions

Charcot-Marie-Tooth disease dominant intermediate F

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 5.3	GERP 1.3, phastCons 1
Overall
CADD	8.338	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.011% South Asian · 10/91,082 alleles

Filtering AF 0.00594% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00453%

Overall 0.000681% 11/1,614,128 alleles · ultra-rare exomes 10/1,461,840 · genomes 1/152,288 · joint denominator

Ancestry group	Frequency	1 in
South Asiangrpmax	0.011%	9,108
European (non-Finnish)	8.47e-05%	1,179,999

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: GNB4
Protein: p.Phe278=
Coding: c.834C>T
MANE Select: NM_021629
dbSNP: rs540700486
Type: single nucleotide variant
Location: chr3:179405272 (GRCh38)
Gene constraint: LOEUF 0.863 · pLI <0.01 · ClinGen HI 0/3 (gnomAD)
Structure: AlphaFold pLDDT 97.14

Full GNB4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Charcot-Marie-Tooth disease dominant intermediate F — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Autosomal dominant intermediate Charcot-Marie-Tooth disease type F (Orphanet):

Inheritance: Autosomal dominant
Onset: All ages

Similar variants

GNB4 p.Phe278Leu Uncertain significance ★ ⚠ same residue
GNB4 p.Gly77Arg Pathogenic ★★ same condition
GNB4 p.Lys57Glu Pathogenic/Likely pathogenic ★★ same condition
GNB4 c.497+1G>C Uncertain significance ★★ same condition
GNB4 p.Arg137Ter Uncertain significance ★★ same condition
GNB4 p.Arg15Trp Uncertain significance ★★ ⚠ same condition
GNB4 p.Arg214Ter Uncertain significance ★★ same condition
GNB4 p.Arg22Gln 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/gnb4-p-phe278 (accessed [today's date]).

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