Traits

Traits linked to CLCN2

chloride voltage-gated channel 2

The Human Phenotype Ontology links 37 traits to CLCN2, 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
Limb ataxia	Always
EEG with polyspike wave complexes	Very often (80–99%)
Generalized-onset seizure	Very often (80–99%)
Morning myoclonic jerks	Very often (80–99%)
Action tremor	Often (30–79%)
Headache	Often (30–79%)
Inability to coordinate movements when walking	Often (30–79%)
Brief seizures with staring spells	Sometimes (5–29%)
Febrile seizure (within the age range of 3 months to 6 years)	Sometimes (5–29%)
Generalized myoclonic seizure	Sometimes (5–29%)
Photosensitive tonic-clonic seizure	Sometimes (5–29%)
Aggressive behavior	Rarely (1–4%)
Repeated seizures without recovery between them	Rarely (1–4%)
Intellectual disability	Not recorded
Leukoencephalopathy	Not recorded
Morning generalized tonic-clonic seizures	Not recorded

Abnormality of the endocrine system

Trait	How often it is seen
Abnormal circulating renin	Very often (80–99%)
Glucocortocoid-insensitive primary hyperaldosteronism	Very often (80–99%)
Secretory adrenocortical adenoma	Often (30–79%)
Enlarged adrenal glands	Sometimes (5–29%)
Dexamethasone-suppressible primary hyperaldosteronism	Not recorded
Elevated plasma aldosterone	Not recorded

Abnormality of the eye

Trait	How often it is seen
Abnormality of eye movement	Often (30–79%)
Damaged optic nerve	Often (30–79%)
Partial loss of field of vision	Often (30–79%)
Chorioretinal atrophy	Sometimes (5–29%)
Choroidal neovascularization	Sometimes (5–29%)
Retinoschisis	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Bleeding within the skull	Sometimes (5–29%)
Bloody nose	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Low blood potassium levels	Always
Metabolic alkalosis	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Abnormality of the mouth	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
High blood pressure	Always

Abnormality of the digestive system

Trait	How often it is seen
Nausea	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Ringing in ears	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle weakness	Sometimes (5–29%)

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 CLCN2 and how often each is seen. Find out more at hpo.jax.org.

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