Traits

Traits linked to SPTSSA

serine palmitoyltransferase small subunit A

The Human Phenotype Ontology links 22 traits to SPTSSA, 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
Delayed ability to walk	Always
Delayed speech and language development	Always
Epilepsy	Always
Intellectual disability	Always
Absent speech development	Often (30–79%)
Difficulty sleeping	Often (30–79%)
Dystonia	Often (30–79%)
Tethered cord	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Appendicular spasticity	Always
Joint contracture	Always
Low muscle tone in trunk	Always
Scoliosis	Always
Spastic walk	Always

Abnormality of head or neck

Trait	How often it is seen
Big calvaria	Often (30–79%)
Drooling	Often (30–79%)

Abnormality of the digestive system

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

Growth abnormality

Trait	How often it is seen
Faltering weight	Always
Short stature	Always

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Always

Abnormality of the eye

Trait	How often it is seen
Close sighted	Always

Abnormality of the integument

Trait	How often it is seen
port-wine stain	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 SPTSSA and how often each is seen. Find out more at hpo.jax.org.

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