Is CHKB p.Pro66Thr (c.196C>A) pathogenic?

CHKB p.Pro66Thr (c.196C>A) is classified Uncertain significance in CHKB (ClinVar, Multiple submitters, 2 submitters; last evaluated 2022-08-08). AlphaMissense: likely benign (0.1263); Very rare (popmax 0.00937%, afr); Associated with Inborn genetic diseases.

What condition is associated with CHKB p.Pro66Thr (c.196C>A)?

CHKB p.Pro66Thr (c.196C>A) is associated with Inborn genetic diseases, megaconial type congenital muscular dystrophy (ClinVar).

How common is CHKB p.Pro66Thr (c.196C>A) in the general population?

CHKB p.Pro66Thr (c.196C>A) is very rare (popmax 0.00937%, afr) (gnomAD).

What do computational predictors say about CHKB p.Pro66Thr (c.196C>A)?

AlphaMissense predicts likely benign (score 0.1263) — an in-silico prediction, not a clinical call.

CHKB p.Pro66Thr

c.196C>A · rs141533752 · VCV1496086

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.1263 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00937%, afr)

Missense predictors

1/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Inborn genetic diseases

Computational evidence

Protein change
AlphaMissense	0.1263	likely benign
REVEL	0.043	moderately benign-leaning
SaProt	LLR -10.91	damaging
⇒ SaProt calls this damaging; AlphaMissense and REVEL do not.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.8	GERP 1.8, phastCons 1
Regional constraint	o/e 1.03	unconstrained · MANE · 3,597 bp · p 0.53 · regional, not allelic
Overall
CADD	21.7	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00937% African / African-American · 7/74,712 alleles

Filtering AF 0.00438% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0031%

Overall 0.000435% 7/1,610,172 alleles · very rare

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: CHKB
Protein: p.Pro66Thr
Coding: c.196C>A
MANE Select: NM_005198
dbSNP: rs141533752
Type: single nucleotide variant
Location: chr22:50582586 (GRCh38)
Gene constraint: LOEUF 1.015 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 86.54 · 3 PDB
Residue 66: a UniProt-annotated variant site (in mdcmc; loss of choline kinase activity; decreased amount of phosphatidylcholine in patients cells); an α-helix

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

Disease context

Inborn genetic diseases — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: megaconial type congenital muscular dystrophy

Similar variants

CHKB p.Gln51Ter Pathogenic/Likely pathogenic ★★ same condition
CHKB c.*208T>G Uncertain significance ★★ same condition
CHKB p.Ala361Val Uncertain significance ★★ ⚠ same condition
CHKB p.Arg344Trp Uncertain significance ★★ ⚠ same condition
CHKB p.Arg62Cys Uncertain significance ★★ ⚠ same condition
CHKB p.Gln309Glu Uncertain significance ★★ same condition
CHKB p.Glu214Asp Uncertain significance ★★ ⚠ same condition
CHKB p.Glu336Lys 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/chkb-p-pro66thr (accessed [today's date]).

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