Is CHAT c.933+18T>C pathogenic?

CHAT c.933+18T>C is classified Likely benign in CHAT (ClinVar, Single submitter, 1 submitter; last evaluated 2023-06-14). Absent from gnomAD v4.1; Associated with congenital myasthenic syndrome 6.

What condition is associated with CHAT c.933+18T>C?

CHAT c.933+18T>C is associated with congenital myasthenic syndrome 6 (ClinVar).

How common is CHAT c.933+18T>C in the general population?

CHAT c.933+18T>C is absent from gnomAD v4.1 (gnomAD).

CHAT c.933+18T>C

rs2496353736 · VCV2998874

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 6

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
Splice region	donor +18	near-intronic (+18 nt from the splice site)
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -0.48	GERP -4.2
Non-coding constraint	Z 1.46	1 kb window · o/e 0.90 · regional · uncalibrated
Overall
CADD	10.57	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: CHAT
Coding: c.933+18T>C
MANE Select: NM_020549
dbSNP: rs2496353736
Type: single nucleotide variant
Location: chr10:49625671 (GRCh38)
Gene constraint: LOEUF 0.973 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 84.73 · 8 PDB

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

Disease context

congenital myasthenic syndrome 6 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

CHAT c.1282-2A>T Likely pathogenic ★★ same condition
CHAT c.1840-9A>G Pathogenic/Likely pathogenic ★★ same condition
CHAT c.698+1G>T Likely pathogenic ★★ same condition
CHAT c.698+2T>C Likely pathogenic ★★ same condition
CHAT p.Ala557Thr Pathogenic/Likely pathogenic ★★ same condition
CHAT p.Arg151Ter Pathogenic/Likely pathogenic ★★ same condition
CHAT p.Arg207Gly Likely pathogenic ★★ same condition
CHAT p.Arg207His Pathogenic/Likely pathogenic ★★ ⚠ 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/chat-c-933-plus-18t-c (accessed [today's date]).

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