Is CHRNB1 p.Asp136= (c.408C>T) pathogenic?

CHRNB1 p.Asp136= (c.408C>T) is classified Likely benign in CHRNB1 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-07-25). Absent from gnomAD v4.1; Associated with congenital myasthenic syndrome 2A.

What condition is associated with CHRNB1 p.Asp136= (c.408C>T)?

CHRNB1 p.Asp136= (c.408C>T) is associated with congenital myasthenic syndrome 2A (ClinVar).

How common is CHRNB1 p.Asp136= (c.408C>T) in the general population?

CHRNB1 p.Asp136= (c.408C>T) is absent from gnomAD v4.1 (gnomAD).

CHRNB1 p.Asp136=

c.408C>T · rs983967827 · VCV3003060

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

congenital myasthenic syndrome 2A

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 -6.5	GERP -4.9
Overall
CADD	2.132	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: CHRNB1
Protein: p.Asp136=
Coding: c.408C>T
MANE Select: NM_000747
dbSNP: rs983967827
Type: single nucleotide variant
Location: chr17:7447097 (GRCh38)
Gene constraint: LOEUF 1.047 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 80.01 · 25 PDB
Residue 136: a β-strand

Full CHRNB1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

congenital myasthenic syndrome 2A — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

CHRNB1 p.Asp136Gly Uncertain significance ★★ ⚠ same residue
CHRNB1 p.Asp136Tyr Uncertain significance ★ same residue
CHRNB1 p.Arg243Cys Pathogenic/Likely pathogenic ★★ same condition
CHRNB1 p.Glu275Ter Pathogenic/Likely pathogenic ★★ same condition
CHRNB1 p.Val289Met Pathogenic ★★ ⚠ same condition
CHRNB1 c.1218-3C>T Uncertain significance ★★ same condition
CHRNB1 c.1365+5G>C Uncertain significance ★★ same condition
CHRNB1 p.Ala105Val 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/chrnb1-p-asp136 (accessed [today's date]).

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