Traits

Traits linked to EXOSC9

exosome component 9

The Human Phenotype Ontology links 61 traits to EXOSC9, 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
Global developmental delay	Always
Absent/small cerebellum	Very often (80–99%)
Decreased reflex response	Very often (80–99%)
Degeneration of anterior horn cells	Very often (80–99%)
Motor delay	Very often (80–99%)
Brisk reflexes	Often (30–79%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Epilepsy	Often (30–79%)
Hypoplasia of the pons	Often (30–79%)
Motor axonal neuropathy	Often (30–79%)
Muscle twitch	Often (30–79%)
Cerebellar cyst	Sometimes (5–29%)
Increased reflexes	Sometimes (5–29%)
Peripheral axonal neuropathy	Sometimes (5–29%)
Thin corpus callosum	Sometimes (5–29%)
Ataxia	Rarely (1–4%)
Degeneration of cerebrum	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Always
Low muscle tone	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Appendicular hypotonia	Often (30–79%)
Diffuse skeletal muscle wasting	Often (30–79%)
Generalized muscle weakness	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Low muscle tone in trunk	Often (30–79%)
Multiple joint contractures	Often (30–79%)
Poor head control	Often (30–79%)
Arthrogryposis multiplex congenita	Rarely (1–4%)
Flexed joint that cannot be straightened	Not recorded

Abnormality of the eye

Trait	How often it is seen
Congenital nystagmus	Often (30–79%)
Gaze-evoked nystagmus	Often (30–79%)
Horizontal nystagmus	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Inward turning cross eyed	Often (30–79%)
Optic atrophy	Often (30–79%)
Progressive loss of vision	Often (30–79%)
Cross-eyed	Sometimes (5–29%)
Wide-set eyes	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Often (30–79%)
High palate	Often (30–79%)
Progressively abnormally small cranium	Often (30–79%)
Tongue twitching	Often (30–79%)
Abnormal facial shape	Not recorded
Eye folds	Not recorded
Short neck	Not recorded

Abnormality of prenatal development or birth

Trait	How often it is seen
Fetal distress	Often (30–79%)
Less than 10 fetal movements in 12 hours	Often (30–79%)
Low levels of amniotic fluid	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory failure	Very often (80–99%)
Congenital laryngeal stridor	Sometimes (5–29%)
Respiratory function loss	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Often (30–79%)
Oral-pharyngeal dysphagia	Not recorded

Growth abnormality

Trait	How often it is seen
Faltering weight	Often (30–79%)
Prenatal growth deficiency	Not recorded

Abnormality of limbs

Trait	How often it is seen
Inward turned thumb	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Not recorded

Abnormality of the immune system

Trait	How often it is seen
Recurrent respiratory infections	Often (30–79%)

Abnormality of the voice

Trait	How often it is seen
Weak cry	Always

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 EXOSC9 and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test