DENND1B

Chr 1

DENN domain containing 1B

Also known as: C1ORF18, C1orf218, FAM31B

NCBI Gene: 163486 ENSG00000213047 UniProt: Q6P3S1

Clathrin (see MIM 118955)-mediated endocytosis is a major mechanism for internalization of proteins and lipids. Members of the connecdenn family, such as DENND1B, function as guanine nucleotide exchange factors (GEFs) for the early endosomal small GTPase RAB35 (MIM 604199) and bind to clathrin and clathrin adaptor protein-2 (AP2; see MIM 601024). Thus, connecdenns link RAB35 activation with the clathrin machinery (Marat and McPherson, 2010 [PubMed 20154091]).[supplied by OMIM, Nov 2010]

Primary Disease Associations & Inheritance

UniProtAsthma

Active trials

Pathogenic / LP

ClinVar variants

Pubs (1 yr)

0.3

Missense Z

0.49

LOEUF

Clinical Summary— DENND1B

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Population Constraint (gnomAD)

Constrained for loss-of-function variants (OE-LoF 0.25) despite low pLI — interpret in context.

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ClinVar Variants

20 Pathogenic / Likely Pathogenic· 46 VUS of 72 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Moderate LoF intolerance

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.

0.49LOEUF

pLI 0.204

Z-score 3.45

OE 0.25 (0.13–0.49)

Moderately constrained

More LoF-intolerant than ~75% of genes

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.

0.33Z-score

OE missense 0.93 (0.83–1.05)

191 obs / 204.4 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.0.25 (0.13–0.49)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.93 (0.83–1.05)

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.1.00

0≤1.21.6

LoF obs/exp: 6 / 24.4Missense obs/exp: 191 / 204.4Syn Z: 0.01

0.6745th %ile

GOF

0.6637th %ile

LOF

0.3941th %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.