Is AP4E1 p.Ile426= (c.1278C>T) pathogenic?

AP4E1 p.Ile426= (c.1278C>T) is classified Likely benign in AP4E1 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-01-05). Ultra-rare (popmax 0.0856%, sas); Associated with Spastic paraplegia.

What condition is associated with AP4E1 p.Ile426= (c.1278C>T)?

AP4E1 p.Ile426= (c.1278C>T) is associated with Spastic paraplegia (ClinVar).

How common is AP4E1 p.Ile426= (c.1278C>T) in the general population?

AP4E1 p.Ile426= (c.1278C>T) is ultra-rare (popmax 0.0856%, sas) (gnomAD).

AP4E1 p.Ile426=

c.1278C>T · VCV4743175

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0856%, sas)

Conditions

Spastic paraplegia

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP -1.2	GERP -3.4
Overall
CADD	5.979	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0856% South Asian · 78/91,080 alleles

Filtering AF 0.0703% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0646%

Overall 0.00514% 83/1,613,782 alleles · ultra-rare exomes 81/1,461,636 · genomes 2/152,146 · joint denominator

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0856%	1,168
Middle Eastern	0.0329%	3,040
Remaining individualsnot grpmax-eligible	0.0032%	31,234
African / African-American	0.00134%	74,904

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: AP4E1
Protein: p.Ile426=
Coding: c.1278C>T
MANE Select: NM_007347
Type: single nucleotide variant
Location: chr15:50948121 (GRCh38)
Gene constraint: LOEUF 0.576 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 72.42 · 4 PDB
Residue 426: a UniProt-annotated variant site (in)

Full AP4E1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Spastic paraplegia — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

AP4E1 p.Ile426Leu Conflicting classifications of pathogenicity ★ ⚠ same residue
AP4E1 p.Arg304Ter Pathogenic/Likely pathogenic ★★ same condition
AP4E1 p.Ala119Ser Uncertain significance ★★ ⚠ same condition
AP4E1 p.Ala45Thr Uncertain significance ★★ ⚠ same condition
AP4E1 p.Ala475Val Uncertain significance ★★ ⚠ same condition
AP4E1 p.Arg646Cys Uncertain significance ★★ same condition
AP4E1 p.Asn1086Ser Uncertain significance ★★ ⚠ same condition
AP4E1 p.Asp484Val 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/ap4e1-p-ile426 (accessed [today's date]).

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