Is APBA3 p.Arg443Cys (c.1327C>T) pathogenic?

APBA3 p.Arg443Cys (c.1327C>T) is classified Uncertain significance in APBA3 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-06-16). AlphaMissense: likely benign (0.335); Ultra-rare (popmax 0.0249%, sas).

How common is APBA3 p.Arg443Cys (c.1327C>T) in the general population?

APBA3 p.Arg443Cys (c.1327C>T) is ultra-rare (popmax 0.0249%, sas) (gnomAD).

What do computational predictors say about APBA3 p.Arg443Cys (c.1327C>T)?

AlphaMissense predicts likely benign (score 0.335) — an in-silico prediction, not a clinical call.

APBA3 p.Arg443Cys

c.1327C>T · VCV4117239

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.335 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0249%, sas)

Missense predictors

1/2 damaging

AlphaMissense, SaProt · REVEL no call

Computational evidence

Protein change
AlphaMissense	0.335	likely benign
REVEL	0.415	indeterminate
SaProt	LLR -10.85	damaging
⇒ SaProt calls this damaging; AlphaMissense does not; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 8.3	GERP 2.1, phastCons 1
Regional constraint	o/e 1.05	unconstrained · MANE · 9,235 bp · p 0.12 · regional, not allelic
Overall
CADD	31.0	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 0.0249% South Asian · 22/88,240 alleles

Filtering AF 0.0169% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0142%

Overall 0.00176% 28/1,587,594 alleles · ultra-rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0249%	4,011
Middle Eastern	0.017%	5,888
Remaining individualsnot grpmax-eligible	0.00648%	15,423
Admixed American	0.00176%	56,800

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: APBA3
Protein: p.Arg443Cys
Coding: c.1327C>T
MANE Select: NM_004886
Type: single nucleotide variant
Location: chr19:3752576 (GRCh38)
Gene constraint: LOEUF 1.237 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 64.79 · 3 PDB
Residue 443: the pdz 1 domain; a β-strand

Full APBA3 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

APBA3 p.Ala158Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala202Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala223Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala308Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala317Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala335Thr Uncertain significance ★ ⚠ same type
APBA3 p.Ala335Val Uncertain significance ★ ⚠ same type
APBA3 p.Ala351Thr Uncertain significance ★ ⚠ same type

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/apba3-p-arg443cys (accessed [today's date]).

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