CCDC88A

Chr 2AR

coiled-coil and HOOK domain protein 88A

Also known as: APE, GIRDIN, GIV, GRDN, HkRP1, KIAA1212, PEHO, PEHOL

The protein functions as a bifunctional modulator of G proteins, acting as both a guanine nucleotide exchange factor for G(i) alpha subunits and a dissociation inhibitor for G(s) alpha subunits, while also serving as an actin-binding protein essential for cytoskeleton integrity, cell migration, and ciliogenesis. Autosomal recessive mutations cause PEHO syndrome-like disorder, a severe early-onset neurodevelopmental condition. The gene is highly constrained against loss-of-function variants (pLI ~1.0, LOEUF 0.13), indicating strong evolutionary pressure to maintain protein function.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismARLOEUF 0.131 OMIM phenotype
Clinical SummaryCCDC88A
Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

LoF intolerant — likely haploinsufficient
LoF Constraint
0.13LOEUF
pLI 1.000
Z-score 8.66
OE 0.07 (0.040.13)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint
2.35Z-score
OE missense 0.78 (0.730.83)
678 obs / 873.4 exp
Mild constraint

Moderately missense-constrained (top ~2.5%)

Observed / Expected Ratios
LoF OE0.07 (0.040.13)
00.351.4
Missense OE0.78 (0.730.83)
00.61.4
Synonymous OE1.01
01.21.6
LoF obs/exp: 7 / 100.8Missense obs/exp: 678 / 873.4Syn Z: -0.18
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
moderateCCDC88A-related PEHO-like syndrome with neuronal migration disorder, seizures and microcephalyLOFAR

Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.

DN
0.4189th %ile
GOF
0.4481th %ile
LOF
0.71top 10%

The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

CCDC88A · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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