Traits

Traits linked to CACNA1C

calcium voltage-gated channel subunit alpha1 C

The Human Phenotype Ontology links 87 traits to CACNA1C, by body system: features seen in people with one of the gene's rare conditions.

CACNA1C

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased blood pressure in blood vessels of lungs	Always
Prolonged QT interval	Always
Prolonged QTc interval	Always
Interruption of electrical communication between upper and lower chambers of heart	Very often (80–99%)
Slow heartbeats	Very often (80–99%)
Complete right bundle branch block	Often (30–79%)
Enlarged heart	Often (30–79%)
Fainting spell	Often (30–79%)
Heart stops beating	Often (30–79%)
Patent ductus arteriosus	Often (30–79%)
ST segment elevation	Often (30–79%)
Ventricular tachycardia	Often (30–79%)
Aborted sudden cardiac death	Sometimes (5–29%)
Elevated heart rate	Sometimes (5–29%)
First degree atrioventricular block	Sometimes (5–29%)
Hole in heart wall separating two lower heart chambers	Sometimes (5–29%)
Paroxysmal ventricular tachycardia	Sometimes (5–29%)
Patent foramen ovale	Sometimes (5–29%)
Sick sinus syndrome	Sometimes (5–29%)
Sinus bradycardia	Sometimes (5–29%)
Sudden cardiac death	Sometimes (5–29%)
Supraventricular tachycardia	Sometimes (5–29%)
Tetralogy of Fallot	Sometimes (5–29%)
Ventricular fibrillation	Sometimes (5–29%)
Trifascicular block	Rarely (1–4%)
Ventricular arrhythmia	Rarely (1–4%)
J wave	Not recorded
Quivering upper heart chambers resulting in irregular heartbeat	Not recorded
Shortened QT interval	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Central sleep apnea	Always
Delayed motor skills	Always
Delayed speech and language development	Always
Global developmental delay	Always
Myoclonic seizure	Always
Obstructive sleep apnea	Always
Seizure affecting one half of brain	Always
Tonic seizure	Always
Autism	Often (30–79%)
Balance impairment	Often (30–79%)
Epilepsy	Often (30–79%)
Motor delay	Often (30–79%)
Attention deficit	Sometimes (5–29%)
Intellectual disability	Sometimes (5–29%)
Intention tremor	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Decreased depth of eye sockets	Always
Decreased size of tooth	Always
Decreased volume of lip	Always
Depressed nasal bridge	Always
Downturned corners of mouth	Always
Frontal bossing	Always
Little lower jaw	Always
Narrow mouth	Always
Round face	Always
Sparse scalp hair	Always
Thin red part of the upper lip	Always

Abnormality of limbs

Trait	How often it is seen
3-4 finger cutaneous syndactyly	Always
Club feet	Always
Cutaneous syndactyly	Always
Webbed skin of 2nd-3rd toes	Always
Dropped arches	Sometimes (5–29%)
Pes valgus	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Appendicular hypotonia	Always
Flexed joint that cannot be straightened	Always
Low muscle tone in trunk	Always
Permanent flexion of the finger or toe	Always
Low muscle tone	Often (30–79%)
Lower limb spasticity	Rarely (1–4%)

Abnormality of the digestive system

Trait	How often it is seen
Acid reflux	Always
Constipation	Always
Narrowing of anal opening	Always
Poor swallowing	Always

Abnormality of the immune system

Trait	How often it is seen
Recurrent infections	Often (30–79%)
Bronchitis	Sometimes (5–29%)
Pneumonia	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Low blood calcium levels	Often (30–79%)
Low blood sugar	Often (30–79%)
Hypothermia	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Bulging eye	Always
Optic nerve hypoplasia	Always

Abnormality of the respiratory system

Trait	How often it is seen
Noisy breathing	Always
Softening of voice box tissue	Always

Abnormality of prenatal development or birth

Trait	How often it is seen
Only one artery in umbilical cord instead of two	Sometimes (5–29%)

Abnormality of the breast

Trait	How often it is seen
Inverted nipples	Always

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Always

Abnormality of the endocrine system

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

Constitutional symptom

Trait	How often it is seen
Sudden death	Not recorded

Growth abnormality

Trait	How often it is seen
Growth delay as children	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 CACNA1C and how often each is seen. Find out more at hpo.jax.org.

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