AP4B1

Chr 1AR

adaptor related protein complex 4 subunit beta 1

Also known as: BETA-4, CPSQ5, SPG47

NCBI Gene: 10717ENSG00000134262UniProt: Q9Y6B7OMIM: 607245

This gene encodes a subunit of a heterotetrameric adapter-like complex 4 that is involved in targeting proteins from the trans-Golgi network to the endosomal-lysosomal system. Mutations in this gene are associated with cerebral palsy spastic quadriplegic type 5 (CPSQ5) disorder. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2011]

GeneReviewsOMIMResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Spastic paraplegia 47, autosomal recessiveMIM #614066
AR

Clinical highlights

Gene-disease validity (ClinGen)
AP-4 deficiency syndrome · ARDefinitivesufficient evidence for diagnostic panels
Interpreting a novel variant
Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.
1
Active trials
10
Pubs (1 yr)
—
P/LP submissions
—
P/LP missense
0.83
LOEUF
LOF
Mechanism· G2P
📖
GeneReview available — AP4B1
Authoritative clinical overview · Recommended first read
Open GeneReview ↗

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?
0.83LOEUF
pLI 0.000
Z-score 2.37
OE 0.57 (0.40–0.83)
Tolerant

Typical tolerance to LoF variation

Missense Constraint?
0.13Z-score
OE missense 0.98 (0.90–1.07)
398 obs / 405.4 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?
LoF OE?0.57 (0.40–0.83)
0≤0.351.4
Missense OE?0.98 (0.90–1.07)
0≤0.61.4
Synonymous OE?1.01
0≤1.21.6
LoF obs/exp: 20 / 35.1Missense obs/exp: 398 / 405.4Syn Z: -0.06

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

AP4B1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients