Is AFG2A p.Pro21= (c.63C>T) pathogenic?

AFG2A p.Pro21= (c.63C>T) is classified Likely benign in AFG2A (ClinVar, Single submitter, 1 submitter; last evaluated 2023-07-06). Very rare (popmax 0.00133%, afr); Associated with microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome.

How common is AFG2A p.Pro21= (c.63C>T) in the general population?

AFG2A p.Pro21= (c.63C>T) is very rare (popmax 0.00133%, afr) (gnomAD).

AFG2A p.Pro21=

Q: What condition is associated with AFG2A p.Pro21= (c.63C>T)?

AFG2A p.Pro21= (c.63C>T) is associated with microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome (ClinVar).

c.63C>T · VCV3747874

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00133%, afr)

Conditions

microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome

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 -1.7	GERP -3.4
Overall
CADD	5.323	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00133% African / African-American · 1/75,060 alleles

Filtering AF 0.000183% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00012%

Overall 0.000434% 7/1,614,256 alleles · very rare exomes 6/1,461,888 · genomes 1/152,368 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00133%	75,060
European (non-Finnish)	0.000508%	196,675

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: AFG2A
Protein: p.Pro21=
Coding: c.63C>T
MANE Select: NM_145207
Type: single nucleotide variant
Location: chr4:122923205 (GRCh38)
Structure: AlphaFold pLDDT 73.21 · 2 PDB
Residue 21: the 'required for interaction with afg2b and cinp' region; the 'disordered' region

Full AFG2A gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

AFG2A p.Pro21Ser Conflicting classifications of pathogenicity ★ ⚠ same residue
AFG2A c.1714+1G>A Pathogenic ★★ same condition
AFG2A c.446+1G>A Likely pathogenic ★★ same condition
AFG2A p.Ala844Val Pathogenic/Likely pathogenic ★★ same condition
AFG2A p.Arg445Ter Pathogenic/Likely pathogenic ★★ same condition
AFG2A p.Arg510Ter Pathogenic/Likely pathogenic ★★ same condition
AFG2A p.Arg514Ter Pathogenic/Likely pathogenic ★★ same condition
AFG2A p.Arg538Ter 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/afg2a-p-pro21 (accessed [today's date]).

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