Traits

Traits linked to CACNA1S

calcium voltage-gated channel subunit alpha1 S

The Human Phenotype Ontology links 87 traits to CACNA1S, by body system: features seen in people with one of the gene's rare conditions.

CACNA1S

Abnormality of the musculoskeletal system

Trait	How often it is seen
Axial muscle weakness	Always
Episodic flaccid weakness	Always
Low muscle tone	Always
Abnormal muscle fiber morphology	Very often (80–99%)
EMG abnormality	Very often (80–99%)
Increased variability in muscle fiber diameter	Very often (80–99%)
Breakdown of skeletal muscle	Often (30–79%)
Exercise-induced muscle fatigue	Often (30–79%)
Increased endomysial connective tissue	Often (30–79%)
Intermittent painful muscle spasms	Often (30–79%)
Muscle spasm	Often (30–79%)
Muscle stiffness	Often (30–79%)
Scoliosis	Often (30–79%)
Acute rhabdomyolysis	Sometimes (5–29%)
Centrally nucleated skeletal muscle fibers	Sometimes (5–29%)
Decreased lung function due to weak breathing muscles	Sometimes (5–29%)
Exercise-induced rhabdomyolysis	Sometimes (5–29%)
Fatty replacement of skeletal muscle	Sometimes (5–29%)
Late-onset proximal muscle weakness	Sometimes (5–29%)
Muscle tissue disease	Sometimes (5–29%)
Necrotizing myopathy	Sometimes (5–29%)
Fatigable weakness of respiratory muscles	Rarely (1–4%)
Respiratory paralysis	Rarely (1–4%)
Muscle weakness	Not recorded
Myotonia	Not recorded

Laboratory abnormality

Trait	How often it is seen
Low blood potassium levels	Always
Recurrent low potassium	Always
Decreased urinary potassium	Very often (80–99%)
Increased intramyocellular lipid droplets	Very often (80–99%)
Low blood magnesium levels	Very often (80–99%)
Low blood phosphate level	Very often (80–99%)
Mildly elevated creatine kinase	Very often (80–99%)
Fever	Often (30–79%)
High blood phosphate levels	Often (30–79%)
Malignant hyperthermia	Often (30–79%)
Metabolic acidosis	Often (30–79%)
Postprandial hyperglycemia	Often (30–79%)
Elevated blood creatine phosphokinase	Sometimes (5–29%)
Elevated creatine kinase after exercise	Sometimes (5–29%)
Increased circulating potassium concentration	Sometimes (5–29%)
Myoglobinuria	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Palpitations	Very often (80–99%)
Supraventricular tachycardia	Often (30–79%)
Ventricular tachycardia	Often (30–79%)
Abnormal heart rate	Sometimes (5–29%)
Extra heart beat	Sometimes (5–29%)
High-output congestive heart failure	Sometimes (5–29%)
Prolonged QT interval	Sometimes (5–29%)
Second degree atrioventricular block	Sometimes (5–29%)
Shortened PR interval	Sometimes (5–29%)
Ventricular fibrillation	Sometimes (5–29%)
Elevated heart rate	Not recorded
Impaired myocardial contractility	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Motor delay	Always
Periodic hypokalemic paresis	Always
Periodic paralysis	Always
Paralysis	Very often (80–99%)
Paralysis of all four limbs	Very often (80–99%)
Decreased reflex response	Often (30–79%)
Diminished deep tendon reflex	Often (30–79%)
Tremor	Often (30–79%)
Abnormality of peripheral nerve conduction	Not recorded

Abnormality of the endocrine system

Trait	How often it is seen
Overactive thyroid	Always
Graves disease	Very often (80–99%)
Thyrotoxicosis with diffuse goiter	Very often (80–99%)
Thyrotoxicosis with toxic multinodular goiter	Very often (80–99%)
Thyrotoxicosis with toxic single thyroid nodule	Very often (80–99%)
Adrenocortical adenoma	Rarely (1–4%)
Enlarged thyroid gland in neck	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Constipation	Often (30–79%)
Feeding difficulties	Often (30–79%)
Acute liver failure	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
High palate	Always
Abnormality of masseter muscle	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Eye muscle paralysis	Often (30–79%)
Weakness of muscles controlling eye movement	Rarely (1–4%)

Abnormality of the genitourinary system

Trait	How often it is seen
Urinary retention	Often (30–79%)
Acute kidney injury	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
High blood carbon dioxide level	Often (30–79%)
Increased respiratory rate or depth of breathing	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Obesity	Very often (80–99%)
Weight loss	Often (30–79%)

Abnormal cellular phenotype

Trait	How often it is seen
Cardiomyocyte mitochondrial proliferation	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Abnormality of the coagulation cascade	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Lower limb muscle weakness	Very often (80–99%)

Abnormality of the integument

Trait	How often it is seen
Excessive sweating	Very often (80–99%)

Constitutional symptom

Trait	How often it is seen
Pain	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 CACNA1S and how often each is seen. Find out more at hpo.jax.org.

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