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NDUFB11
NADH:ubiquinone oxidoreductase subunit B11
NDUFB11 is located on the short (p) arm of chromosome X, at band Xp11.3. Arm ratio per GRCh38 - banding schematic.
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Overview
NDUFB11 encodes NADH:ubiquinone oxidoreductase subunit B11, a protein component of mitochondrial respiratory chain complex I. Complex I represents the entry point for electrons into the mitochondrial respiratory chain, catalysing the transfer of electrons from NADH to ubiquinone whilst pumping protons across the inner mitochondrial membrane. This process generates the electrochemical gradient that drives ATP synthesis, the primary energy currency of cells. The NDUFB11 subunit contributes to the structural integrity and functional coordination of this large multi-protein assembly composed of numerous different protein subunits.
What the gene does
The NDUFB11 protein functions as an accessory subunit within the membrane arm of complex I, supporting the enzyme's electron transfer and proton translocation activities. Complex I oxidises NADH produced during glycolysis and the citric acid cycle, transferring electrons through a series of iron-sulphur clusters to ubiquinone in the inner mitochondrial membrane. This electron flow is coupled to the movement of protons from the mitochondrial matrix to the intermembrane space, establishing the proton-motive force required for ATP synthase activity. Whilst NDUFB11 does not directly participate in catalysis, it appears to contribute to the assembly and stability of the holocomplex, ensuring efficient electron transfer and preventing the generation of reactive oxygen species that can occur when complex I function is compromised. The precise biochemical role of individual accessory subunits like NDUFB11 remains an active area of research.
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Chromosome location
NDUFB11 is located on the short arm of the X chromosome at position Xp11.3. This chromosomal region contains numerous genes, and its location on the X chromosome means that inheritance patterns and clinical presentation can differ between males and females. Males carry only one copy of X-linked genes, whilst females carry two copies, one on each X chromosome.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein.
Key variants
Genetic variants in NDUFB11 can affect mitochondrial complex I assembly or function. The inheritance pattern for NDUFB11-related conditions varies, reflecting its location on the X chromosome. Males inheriting a pathogenic variant typically express the associated phenotype more fully, as they possess only one copy of the gene. Females may show variable clinical presentations depending on X-inactivation patterns, the random process by which one X chromosome is silenced in each cell during development.
Sample of pathogenic variants
4 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.262C>T | p.Arg88Ter | Pathogenic | ★★☆☆ | Mitochondrial complex I deficiency, nuclear type 1 |
c.270CTT[2] | p.Phe93del | Pathogenic/Likely pathogenic | ★★☆☆ | Mitochondrial complex I deficiency, nuclear type 30 |
c.361G>A | p.Glu121Lys | Pathogenic/Likely pathogenic | ★★☆☆ | NDUFB11-related disorders |
c.372del | p.Arg124fs | Pathogenic | - | Linear skin defects with multiple congenital anomalies 3 |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Alterations in NDUFB11 have been associated with mitochondrial respiratory chain disorders affecting energy production in tissues with high metabolic demands. These conditions can present with diverse clinical features reflecting the widespread role of mitochondria in cellular metabolism. The severity and specific manifestations depend on the nature of the genetic change and the degree to which complex I function is impaired. Clinical presentations may vary considerably between affected individuals, even within the same family.
No disease links recorded for this gene in our reference set.
UK clinical status
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
Why is NDUFB11 located on the X chromosome significant?
The X-chromosomal location means males and females can be affected differently. Males, having only one X chromosome, will express a pathogenic variant if present. Females carry two X chromosomes and may show milder or variable features depending on which copy is active in different cells.
What is mitochondrial complex I?
Complex I is the first and largest enzyme in the mitochondrial respiratory chain, responsible for initiating the process that converts food-derived nutrients into ATP, the cell's energy molecule. It comprises many protein subunits working together to transfer electrons and pump protons across the inner mitochondrial membrane.
How does NDUFB11 contribute to complex I function?
NDUFB11 acts as an accessory subunit that supports the structural integrity and coordinated function of the complex I enzyme assembly. Whilst it does not directly catalyse chemical reactions, it appears important for proper complex assembly and stable electron transfer activity.