Traits

Traits linked to AP1S1

adaptor related protein complex 1 subunit sigma 1

The Human Phenotype Ontology links 24 traits to AP1S1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the digestive system

Trait	How often it is seen
Diarrhea	Always
Abnormality of the intestine	Very often (80–99%)
Impaired release of bile from liver	Often (30–79%)
Scar tissue replaces healthy tissue in the liver	Often (30–79%)
Slowed or blocked flow of bile from liver	Often (30–79%)
Hepatic fibrosis	Sometimes (5–29%)
Jejunal atresia	Sometimes (5–29%)
Microcolon	Sometimes (5–29%)
Volvulus	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Global developmental delay	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Peripheral neuropathy	Very often (80–99%)

Laboratory abnormality

Trait	How often it is seen
Increased circulating very long-chain fatty acid concentration	Always
Copper deficiency	Often (30–79%)
Decreased serum ceruloplasmin	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
High forehead	Always
Upward slanting of the opening between the eyelids	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Ichthyosis	Always
Hyperkeratosis	Very often (80–99%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Redness of skin or mucous membrane	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Very often (80–99%)

Abnormality of the eye

Trait	How often it is seen
Clouding of the lens of the eye	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Very often (80–99%)

Growth abnormality

Trait	How often it is seen
Growth delay	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 AP1S1 and how often each is seen. Find out more at hpo.jax.org.

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