ARL2BP

Chr 16AR

ARF like GTPase 2 binding protein

Also known as: BART, BART1, RP66, RP82

NCBI Gene: 23568 ENSG00000102931 UniProt: Q9Y2Y0

ADP-ribosylation factor (ARF)-like proteins (ARLs) comprise a functionally distinct group of the ARF family of RAS-related GTPases. The protein encoded by this gene binds to ARL2.GTP with high affinity but does not interact with ARL2.GDP, activated ARF, or RHO proteins. The lack of detectable membrane association of this protein or ARL2 upon activation of ARL2 is suggestive of actions distinct from those of the ARFs. This protein is considered to be the first ARL2-specific effector identified, due to its interaction with ARL2.GTP but lack of ARL2 GTPase-activating protein activity. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Retinitis pigmentosa 82 with or without situs inversusMIM #615434

Active trials

Pathogenic / LP

136

ClinVar variants

Pubs (1 yr)

0.8

Missense Z

1.35

LOEUF

Clinical Summary— ARL2BP

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Gene-Disease Validity (ClinGen)

ciliopathy · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

38 Pathogenic / Likely Pathogenic· 59 VUS of 136 total submissions

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GeneReview available — ARL2BP

Authoritative clinical overview · Recommended first read

Open GeneReview ↗

Some data sources returned errors (1)

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

1.35LOEUF

pLI 0.000

Z-score 0.75

OE 0.75 (0.44–1.35)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

0.83Z-score

OE missense 0.75 (0.61–0.92)

64 obs / 85.5 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.75 (0.44–1.35)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.75 (0.61–0.92)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.90

0≤1.21.6

LoF obs/exp: 8 / 10.7Missense obs/exp: 64 / 85.5Syn Z: 0.46

0.81top 10%

GOF

0.72top 25%

LOF

0.1895th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median

GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.