GNG3

Chr 11

G protein subunit gamma 3

Also known as: HG3D

NCBI Gene: 2785 ENSG00000162188 UniProt: P63215

Guanine nucleotide binding proteins are heterotrimeric signal-transducing molecules consisting of alpha, beta, and gamma subunits. The gamma subunit determines the specificity of which signaling pathways will be affected by this particular complex. The protein encoded by this gene represents the gamma subunit of both inhibitory and stimulatory complexes. [provided by RefSeq, Jan 2012]

Active trials

Pathogenic / LP

ClinVar variants

Pubs (1 yr)

1.2

Missense Z

1.22

LOEUF

Clinical Summary— GNG3

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Population Constraint (gnomAD)

Moderately constrained gene (pLI 0.54) — some intolerance to loss-of-function variants.

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ClinVar Variants

13 Pathogenic / Likely Pathogenic· 11 VUS of 38 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.

1.22LOEUF

pLI 0.542

Z-score 1.41

OE 0.00 (0.00–1.22)

Moderately constrained

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.

1.16Z-score

OE missense 0.52 (0.38–0.73)

24 obs / 46.2 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.0.00 (0.00–1.22)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.52 (0.38–0.73)

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.1.10

0≤1.21.6

LoF obs/exp: 0 / 2.3Missense obs/exp: 24 / 46.2Syn Z: -0.31

0.6550th %ile

GOF

0.79top 25%

LOF

0.4726th %ile

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

GOFprediction above median

DNprediction 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.