Traits

Traits linked to COQ4

coenzyme Q4

The Human Phenotype Ontology links 71 traits to COQ4, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Absent reflexes	Always
Balance impairment	Always
Dystonia	Always
EEG with burst suppression	Always
Epilepsy	Always
Focal impaired awareness seizure	Always
Global developmental delay	Always
Hoffmann sign	Always
IQ between 34 and 49	Always
Knee clonus	Always
Lack of coordination of movement	Always
Loss of ability to walk	Always
Overactive lower leg reflex	Very often (80–99%)
Ataxia	Often (30–79%)
Babinski sign	Often (30–79%)
Cerebral infarct	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Degeneration of cerebrum	Often (30–79%)
Elevated brain lactate level by MRS	Often (30–79%)
Epileptic encephalopathy	Often (30–79%)
Generalized dystonia	Often (30–79%)
Grand mal seizures	Often (30–79%)
Hippocampal sclerosis	Often (30–79%)
Inability to coordinate movements when walking	Often (30–79%)
Limb ataxia	Often (30–79%)
Motor delay	Often (30–79%)
Postural tremor	Often (30–79%)
Small cerebellum	Often (30–79%)
Thin corpus callosum	Often (30–79%)
Upper limb hyperreflexia	Often (30–79%)
Cerebellar vermis hypoplasia	Sometimes (5–29%)
Cognitive impairment	Sometimes (5–29%)
Difficulty articulating speech	Sometimes (5–29%)
Focal hemiclonic seizure	Sometimes (5–29%)
Peripheral nerve disease	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Always
Muscle weakness	Always
Scoliosis	Always
Spasticity and rigidity of muscles	Always
Lower limb spasticity	Very often (80–99%)
Distal arthrogryposis	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Muscle tissue disease	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Hole in heart wall separating two lower heart chambers	Always
Enlarged and thickened heart muscle	Often (30–79%)
Severely reduced left ventricular ejection fraction	Often (30–79%)
Slow heartbeats	Often (30–79%)
Underdeveloped left heart	Rarely (1–4%)

Laboratory abnormality

Trait	How often it is seen
Decreased level of coenzyme Q10 in skeletal muscle	Always
High blood ammonia levels	Always
Higher than normal levels of lactate in blood	Very often (80–99%)
2-hydroxyglutarate aciduria	Often (30–79%)
Elevated blood creatine phosphokinase	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Involuntary, rapid, rhythmic eye movements	Always
Cerebral visual impairment	Often (30–79%)
Visual impairment	Often (30–79%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased activity of mitochondrial complex II	Often (30–79%)
Decreased activity of mitochondrial complex III	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
Coarse facial features	Always
Eye folds	Always

Abnormality of prenatal development or birth

Trait	How often it is seen
Caesarean section	Often (30–79%)
Moderate to late preterm birth	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Poor swallowing	Very often (80–99%)
Feeding difficulties	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory function loss	Always
Apnea	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Always
Prenatal growth deficiency	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Abnormal rhythmic movements of ankle	Always

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Persistent blue color of hands or feet	Often (30–79%)

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 COQ4 and how often each is seen. Find out more at hpo.jax.org.

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