IZUMO3

Chr 9

IZUMO family member 3

Also known as: C9orf134, bA20A20.1

The protein plays an important role in acrosome biogenesis during sperm development and enables protein homodimerization activity. Mutations cause male infertility with defects in sperm acrosome formation, following an autosomal recessive inheritance pattern. This gene is not highly constrained against loss-of-function variants, consistent with its specialized reproductive function.

OMIMResearchSummary from RefSeq, UniProt
MultiplemechanismLOEUF 1.73
Clinical SummaryIZUMO3
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
75 unique Pathogenic / Likely Pathogenic· 4 VUS of 83 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.73LOEUF
pLI 0.000
Z-score -0.51
OE 1.15 (0.771.73)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
-0.23Z-score
OE missense 1.06 (0.921.23)
128 obs / 120.9 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios
LoF OE1.15 (0.771.73)
00.351.4
Missense OE1.06 (0.921.23)
00.61.4
Synonymous OE0.99
01.21.6
LoF obs/exp: 15 / 13.0Missense obs/exp: 128 / 120.9Syn Z: 0.06
DN
0.6357th %ile
GOF
0.6932th %ile
LOF
0.3067th %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.

ClinVar Variant Classifications

83 submitted variants in ClinVar

Classification Summary

Pathogenic68
Likely Pathogenic7
VUS4
Likely Benign4
68
Pathogenic
7
Likely Pathogenic
4
VUS
4
Likely Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories· variant type breakdown unavailable

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
68
Likely Pathogenic
7
VUS
4
Likely Benign
4
Benign
0
Total83

Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

IZUMO3 · 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.

Search ClinicalTrials.gov →
Clinical Literature
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