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Traits

Traits linked to NDUFB9

NADH:ubiquinone oxidoreductase subunit B9

The Human Phenotype Ontology links 38 traits to NDUFB9, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

TraitHow often it is seen
AtaxiaVery often (80–99%)
EncephalopathyVery often (80–99%)
Focal T2 hyperintense brainstem lesionVery often (80–99%)
Global developmental delayVery often (80–99%)
LethargyVery often (80–99%)
LeukodystrophyVery often (80–99%)
LeukoencephalopathyVery often (80–99%)
Poor eye contactVery often (80–99%)

Abnormality of the eye

TraitHow often it is seen
Cross-eyedVery often (80–99%)
Damaged optic nerveVery often (80–99%)
Drooping upper eyelidVery often (80–99%)
Involuntary, rapid, rhythmic eye movementsVery often (80–99%)
Optic disc pallorVery often (80–99%)
Paroxysmal involuntary eye movementsVery often (80–99%)
BlindnessSometimes (5–29%)

Laboratory abnormality

TraitHow often it is seen
Higher than normal levels of lactate in bloodAlways
Increased circulating pyruvate concentrationVery often (80–99%)
Increased CSF lactateVery often (80–99%)
Increased lactate in bodyVery often (80–99%)
Low blood sugarVery often (80–99%)
Diabetes mellitusSometimes (5–29%)

Abnormality of the musculoskeletal system

TraitHow often it is seen
Low muscle toneAlways
Mitochondrial myopathyVery often (80–99%)
Muscle weaknessVery often (80–99%)
Poor head controlVery often (80–99%)

Abnormality of the digestive system

TraitHow often it is seen
Enlarged liverVery often (80–99%)
VomitingVery often (80–99%)
Feeding difficultiesSometimes (5–29%)

Abnormal cellular phenotype

TraitHow often it is seen
Decreased activity of mitochondrial complex IAlways
Abnormal mitochondria in muscle tissueVery often (80–99%)

Growth abnormality

TraitHow often it is seen
Faltering weightVery often (80–99%)
Prenatal growth deficiencyVery often (80–99%)

Abnormality of head or neck

TraitHow often it is seen
Abnormally small headSometimes (5–29%)

Abnormality of prenatal development or birth

TraitHow often it is seen
Fetal distressSometimes (5–29%)

Abnormality of the cardiovascular system

TraitHow often it is seen
Enlarged and thickened heart muscleVery often (80–99%)

Abnormality of the ear

TraitHow often it is seen
Sensorineural hearing impairmentVery often (80–99%)

Abnormality of the genitourinary system

TraitHow often it is seen
Proximal tubulopathyVery often (80–99%)

Abnormality of the respiratory system

TraitHow often it is seen
Respiratory function lossVery often (80–99%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to NDUFB9 and how often each is seen. Find out more at hpo.jax.org.

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