NDUFB9
Chr 8ARNADH:ubiquinone oxidoreductase subunit B9
Also known as: B22, CI-B22, LYRM3, MC1DN24, UQOR22
The protein is an accessory subunit of mitochondrial complex I (NADH dehydrogenase) that functions in electron transfer from NADH to ubiquinone in the respiratory chain. Mutations cause mitochondrial complex I deficiency with autosomal recessive inheritance, though the specific clinical phenotype associated with NDUFB9 mutations remains uncertain. Complex I deficiencies typically present with variable manifestations including neonatal disease, cardiomyopathy, liver disease, and neurodegenerative disorders.
Primary Disease Associations & Inheritance
Limited evidence — not for standalone diagnostic reporting
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
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.
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
188 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 1 | 54 | 0 | 55 |
Likely Pathogenic | 0 | 0 | 0 | 0 | 0 |
VUS | 4 | 48 | 10 | 0 | 62 |
Likely Benign | 0 | 2 | 21 | 20 | 43 |
Benign | 0 | 1 | 14 | 1 | 16 |
Conflicting | — | 6 | |||
| Total | 4 | 52 | 99 | 21 | 182 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
NDUFB9 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools