Traits

Traits linked to COA8

cytochrome c oxidase assembly factor 8

The Human Phenotype Ontology links 43 traits to COA8, by body system: features seen in people with one of the gene's rare conditions.

COA8

Abnormality of the nervous system

Trait	How often it is seen
Cavitating leukodystrophy	Always
Loss of developmental milestones	Very often (80–99%)
Progressive leukoencephalopathy	Very often (80–99%)
Progressive peripheral neuropathy	Very often (80–99%)
Abnormal gait	Often (30–79%)
Abnormal pyramidal sign	Often (30–79%)
Ataxia	Often (30–79%)
Delayed speech and language development	Often (30–79%)
Difficulty articulating speech	Often (30–79%)
Epilepsy	Often (30–79%)
Excessive daytime sleepiness	Often (30–79%)
Global developmental delay	Often (30–79%)
Intellectual disability	Often (30–79%)
Motor delay	Often (30–79%)
Nerve damage causing decreased feeling and movement	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Abnormal urinary amino-acid findings	Often (30–79%)
Diffuse hepatic steatosis	Often (30–79%)
Glucose in urine	Often (30–79%)
High urine phosphate levels	Often (30–79%)
High urine protein levels	Often (30–79%)
Increased CSF lactate	Often (30–79%)
Increased lactate in body	Often (30–79%)
Renal Fanconi syndrome	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Spastic tetraparesis	Very often (80–99%)
Decreased lung function due to weak breathing muscles	Often (30–79%)
Fatigable weakness of swallowing muscles	Often (30–79%)
Fatty replacement of skeletal muscle	Often (30–79%)
Generalized decreased muscle tone	Often (30–79%)
Generalized muscle weakness	Often (30–79%)
Cytochrome C oxidase-negative muscle fibers	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Decreased liver function	Often (30–79%)
Enlarged liver	Often (30–79%)
Vomiting	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Drooping upper eyelid	Often (30–79%)
Optic atrophy	Often (30–79%)
Pigmentary retinopathy	Often (30–79%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased activity of mitochondrial complex IV	Always

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low number of red blood cells or hemoglobin	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Enlarged and thickened heart muscle	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Bilateral sensorineural hearing impairment	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Abnormal function of filtrating structures in kidney	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Exertional breathlessness	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Faltering weight	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 COA8 and how often each is seen. Find out more at hpo.jax.org.

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