Traits

Traits linked to TTPA

alpha tocopherol transfer protein

The Human Phenotype Ontology links 46 traits to TTPA, 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
Ataxia	Always
Clumsiness	Always
Degeneration of cerebellum	Always
Delayed somatosensory central conduction time	Always
Difficulty articulating speech	Always
Difficulty performing quick and alternating movements	Always
Dystonia	Always
Impaired proprioception	Always
Lack of coordination of movement	Always
Perseverative thought	Always
Positive Romberg sign	Always
Progressive cerebellar ataxia	Always
Short term memory impairment	Always
Abnormal pyramidal sign	Very often (80–99%)
Absent reflexes	Very often (80–99%)
Babinski sign	Very often (80–99%)
Peripheral neuropathy	Very often (80–99%)
Abnormal speech pattern	Often (30–79%)
Damage to nerves that sense feeling	Often (30–79%)
Head titubation	Often (30–79%)
Loss of developmental milestones	Sometimes (5–29%)
Mental deterioration	Sometimes (5–29%)
Paralysis or weakness of one side of body	Sometimes (5–29%)
Tremor	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Difficulties with night vision	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Abnormal retinal pigmentation	Sometimes (5–29%)
Abnormality of visual evoked potentials	Sometimes (5–29%)
Visual impairment	Sometimes (5–29%)
Pigmentary retinopathy	Rarely (1–4%)

Laboratory abnormality

Trait	How often it is seen
Vitamin E deficiency	Always
Diabetes mellitus	Sometimes (5–29%)
Elevated serum cholesterol	Not recorded
Increased circulating LDL level	Not recorded
Increased plasma triglycerides	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle weakness	Very often (80–99%)
Scoliosis	Often (30–79%)
Muscle degeneration	Sometimes (5–29%)
Spasticity and rigidity of muscles	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal heart rate	Sometimes (5–29%)
Enlarged and thickened heart muscle	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Fatty deposits in skin around the eyes	Not recorded

Abnormality of limbs

Trait	How often it is seen
High-arched foot	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Urinary urgency	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Tendon xanthomatosis	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 TTPA and how often each is seen. Find out more at hpo.jax.org.

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