Is CHRNB2 p.Asp116= (c.348T>C) pathogenic?

CHRNB2 p.Asp116= (c.348T>C) is classified Likely benign in CHRNB2 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2026-02-03). Ultra-rare (popmax 0.0694%, afr); Associated with familial sleep-related hypermotor epilepsy.

What condition is associated with CHRNB2 p.Asp116= (c.348T>C)?

CHRNB2 p.Asp116= (c.348T>C) is associated with familial sleep-related hypermotor epilepsy (ClinVar).

How common is CHRNB2 p.Asp116= (c.348T>C) in the general population?

CHRNB2 p.Asp116= (c.348T>C) is ultra-rare (popmax 0.0694%, afr) (gnomAD).

How is Sleep-related hypermotor epilepsy inherited?

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

CHRNB2 p.Asp116=

c.348T>C · rs78921047 · VCV385232

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0694%, afr)

Conditions

familial sleep-related hypermotor epilepsy

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 0.68	GERP -0.2, phastCons 1
Overall
CADD	10.64	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0694% African / African-American · 52/74,886 alleles

Filtering AF 0.0543% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.049%

Overall 0.00373% 60/1,608,776 alleles · ultra-rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.0694%	1,440
Admixed American	0.01%	9,955
Remaining individualsnot grpmax-eligible	0.00321%	31,148

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: CHRNB2
Protein: p.Asp116=
Coding: c.348T>C
MANE Select: NM_000748
dbSNP: rs78921047
Type: single nucleotide variant
Location: chr1:154570350 (GRCh38)
Gene constraint: LOEUF 1.116 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 81.16 · 15 PDB

Full CHRNB2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

familial sleep-related hypermotor epilepsy — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Sleep-related hypermotor epilepsy (Orphanet):

Inheritance: Autosomal dominant
Onset: Adolescent, Adult, Childhood

Similar variants

CHRNB2 p.Asp116His Uncertain significance ★ ⚠ same residue
CHRNB2 p.Val287Leu Pathogenic/Likely pathogenic ★★ same condition
CHRNB2 p.Val287Met Pathogenic ★★ same condition
CHRNB2 p.Val308Ala Pathogenic/Likely pathogenic ★★ same condition
CHRNB2 c.1338+3G>T Uncertain significance ★★ same condition
CHRNB2 c.366-3C>T Uncertain significance ★★ same condition
CHRNB2 p.Ala135Val Uncertain significance ★★ ⚠ same condition
CHRNB2 p.Ala154Thr 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/chrnb2-p-asp116 (accessed [today's date]).

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