Traits

Traits linked to SLC33A1

solute carrier family 33 member 1

The Human Phenotype Ontology links 34 traits to SLC33A1, 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
Absent speech development	Always
CNS hypomyelination	Always
Degeneration of cerebellum	Always
Degeneration of cerebrum	Always
Inability to walk	Always
Severe global developmental delay	Always
Widened subarachnoid space	Always
Babinski sign	Very often (80–99%)
Degeneration of the lateral corticospinal tracts	Very often (80–99%)
Increased reflexes	Very often (80–99%)
Clonus	Often (30–79%)
Epilepsy	Often (30–79%)
Impaired vibration sensation in the lower limbs	Often (30–79%)
Spinal cord lesion	Often (30–79%)
Abnormal cerebrospinal fluid morphology	Not recorded
Abnormal lower-limb motor evoked potentials	Not recorded
Overactive lower leg reflex	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Lower limb spasticity	Very often (80–99%)
Progressive spastic paraplegia	Very often (80–99%)
Spastic walk	Very often (80–99%)
Lower limb amyotrophy	Often (30–79%)
EMG abnormality	Not recorded
Low muscle tone	Not recorded
Muscle degeneration	Not recorded
Muscle weakness	Not recorded
Spastic paraplegia	Not recorded

Abnormality of limbs

Trait	How often it is seen
Lower limb hypertonia	Very often (80–99%)
Lower limb muscle weakness	Often (30–79%)
High-arched foot	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Clouding of the lens of the eye at birth	Always
Involuntary, rapid, rhythmic eye movements	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Copper deficiency	Always
Decreased serum ceruloplasmin	Always

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	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 SLC33A1 and how often each is seen. Find out more at hpo.jax.org.

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