Traits

Traits linked to NPC1

NPC intracellular cholesterol transporter 1

The Human Phenotype Ontology links 30 traits to NPC1, 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
Inability to coordinate movements when walking	Always
Intellectual disability	Always
Epilepsy	Very often (80–99%)
Ataxia	Not recorded
Cataplexy	Not recorded
Dementia	Not recorded
Difficulty articulating speech	Not recorded
Dystonia	Not recorded
Global developmental delay	Not recorded
Loss of brain cells	Not recorded
Loss of speech	Not recorded
Neurofibrillary tangles	Not recorded
Psychosis	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	Often (30–79%)
Fatal liver failure in infancy	Not recorded
Poor swallowing	Not recorded
Prolonged yellowing of skin in newborn	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased spleen size	Often (30–79%)
CNS foam cells	Not recorded
Foam cells	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Not recorded
Involuntary muscle stiffness, contraction, or spasm	Not recorded
Low muscle tone	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Sea-blue histiocytosis	Always
Bone-marrow foam cells	Not recorded

Laboratory abnormality

Trait	How often it is seen
Low cholesterol esterification rate	Always
Elevated circulating C-triol concentration	Not recorded

Abnormal cellular phenotype

Trait	How often it is seen
Unesterified cholesterol accumulation in cultured fibroblasts	Not recorded

Abnormality of prenatal development or birth

Trait	How often it is seen
Fetal ascites	Not recorded

Abnormality of the eye

Trait	How often it is seen
Vertical supranuclear gaze palsy	Not recorded

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 NPC1 and how often each is seen. Find out more at hpo.jax.org.

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