Traits

Traits linked to KCND3

potassium voltage-gated channel subfamily D member 3

The Human Phenotype Ontology links 43 traits to KCND3, 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
Degeneration of cerebellum	Always
Inability to coordinate movements when walking	Always
Abnormal gait	Very often (80–99%)
Ataxia	Very often (80–99%)
Difficulty articulating speech	Very often (80–99%)
Balance impairment	Often (30–79%)
Decreased reflex response	Often (30–79%)
Impaired vibration sensation at ankles	Often (30–79%)
Increased reflexes	Often (30–79%)
Instability or lack of coordination of central trunk muscles	Often (30–79%)
Limb ataxia	Often (30–79%)
Cognitive impairment	Sometimes (5–29%)
Incoordination	Sometimes (5–29%)
Slurred speech	Sometimes (5–29%)
Wide based walk	Sometimes (5–29%)
Jerking	Not recorded
Postural tremor	Not recorded
Progressive cerebellar ataxia	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Palpitations	Always
ST segment elevation	Always
Complete right bundle branch block	Often (30–79%)
Fainting spell	Often (30–79%)
Heart stops beating	Often (30–79%)
Presyncope	Often (30–79%)
Prolonged QT interval	Often (30–79%)
Elevated heart rate	Sometimes (5–29%)
First degree atrioventricular block	Sometimes (5–29%)
Paroxysmal ventricular tachycardia	Sometimes (5–29%)
Sick sinus syndrome	Sometimes (5–29%)
Supraventricular tachycardia	Sometimes (5–29%)
Ventricular fibrillation	Sometimes (5–29%)
Trifascicular block	Rarely (1–4%)
Ventricular arrhythmia	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Saccadic smooth pursuit interruptions	Often (30–79%)
Double vision	Sometimes (5–29%)
Eye muscle paralysis	Sometimes (5–29%)
Impaired smooth pursuit	Sometimes (5–29%)
Gaze-evoked horizontal nystagmus	Not recorded
Intermittent microsaccadic pursuits	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Poor swallowing	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Loss of bladder control	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Cogwheel rigidity	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 KCND3 and how often each is seen. Find out more at hpo.jax.org.

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