Traits

Traits linked to SPTAN1

spectrin alpha, non-erythrocytic 1

The Human Phenotype Ontology links 96 traits to SPTAN1, 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
Abnormal gait	Always
Babinski sign	Always
Brisk knee jerk	Always
Clumsiness	Always
Decreased compound muscle action potential amplitude	Always
Delayed speech and language development	Always
Epilepsy	Always
High stepping	Always
Impaired vibratory sensation	Always
IQ less than 20	Always
Jerking	Always
Loss of ability to walk	Always
Motor axonal neuropathy	Always
Motor delay	Always
Numbness	Always
Paroxysmal dyskinesia	Always
Peripheral axonal neuropathy	Always
Peripheral neuropathy	Always
Reading disability	Always
Reduced cerebral white matter volume	Always
Seizure affecting one half of brain	Always
Unsteady walk	Always
Wide based walk	Always
Willis-Ekbom disease	Always
Abnormal pyramidal sign	Very often (80–99%)
Hypsarrhythmia	Very often (80–99%)
Infantile spasms	Very often (80–99%)
Loss of developmental milestones	Very often (80–99%)
Abnormality of the nervous system	Often (30–79%)
Ataxia	Often (30–79%)
Atrophy/Degeneration affecting the brainstem	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Intellectual disability	Often (30–79%)
Underdevelopment of part of brain called corpus callosum	Often (30–79%)
Attention deficit	Sometimes (5–29%)
Brief seizures with staring spells	Sometimes (5–29%)
Dystonia	Sometimes (5–29%)
EEG with frontal focal spikes	Sometimes (5–29%)
EEG with polyspike wave complexes	Sometimes (5–29%)
Febrile seizure (within the age range of 3 months to 6 years)	Sometimes (5–29%)
Multifocal epileptiform discharges	Sometimes (5–29%)
Myoclonic seizure	Sometimes (5–29%)
Difficulty articulating speech	Rarely (1–4%)
Focal impaired awareness seizure	Rarely (1–4%)
Grand mal seizures	Rarely (1–4%)
Overactive lower leg reflex	Rarely (1–4%)
Sudden loss of muscle tone	Rarely (1–4%)
CNS hypomyelination	Not recorded
Degeneration of cerebrum	Not recorded
Epileptic encephalopathy	Not recorded
Increased reflexes	Not recorded
Intellectual disability, severe	Not recorded

Abnormality of limbs

Trait	How often it is seen
Areflexia of upper limbs	Always
Bunion	Always
Claw hand deformity	Always
Decreased arm strength	Always
Distal lower limb muscle weakness	Always
Dropped arches	Always
Foot drop	Always
Hammertoe	Always
High-arched foot	Always
Hyporeflexia of lower limbs	Always
Long fingers	Always
Shortening of the achilles tendon	Always
Upper limb amyotrophy	Always
Areflexia of lower limbs	Often (30–79%)
Lower limb muscle weakness	Often (30–79%)
Hyporeflexia of upper limbs	Sometimes (5–29%)
Proximal lower limb muscle weakness	Sometimes (5–29%)
Lower limb hypertonia	Rarely (1–4%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Difficulty walking up stairs	Always
Distal lower limb amyotrophy	Always
Double-Jointed	Always
Frequent falls	Always
Low muscle tone	Always
Pigeon chest	Always
Scoliosis	Always
Spastic tetraplegia	Always
Spastic walk	Always
Weakness of outermost muscles	Always
Muscle degeneration	Often (30–79%)
Spastic paraplegia	Often (30–79%)
Generalized decreased muscle tone	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Always
High palate	Always
Narrow palate	Always
Progressively abnormally small cranium	Always

Abnormality of the eye

Trait	How often it is seen
Damaged optic nerve	Always
Involuntary, rapid, rhythmic eye movements	Always
Cross-eyed	Sometimes (5–29%)

Abnormality of the digestive system

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

Abnormality of the integument

Trait	How often it is seen
Abnormal skin structure	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Lack of energy and strength	Always

Growth abnormality

Trait	How often it is seen
Tall stature	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 SPTAN1 and how often each is seen. Find out more at hpo.jax.org.

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