Traits

Traits linked to MTTP

microsomal triglyceride transfer protein

The Human Phenotype Ontology links 68 traits to MTTP, 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
Abnormality of the nervous system	Very often (80–99%)
Absent reflexes	Often (30–79%)
Ataxia	Sometimes (5–29%)
Babinski sign	Sometimes (5–29%)
Difficulty articulating speech	Sometimes (5–29%)
High stepping	Sometimes (5–29%)
Impaired distal proprioception	Sometimes (5–29%)
Impaired proprioception	Sometimes (5–29%)
Impaired vibratory sensation	Sometimes (5–29%)
Inability to coordinate movements when walking	Sometimes (5–29%)
Lack of coordination of movement	Sometimes (5–29%)
Positive Romberg sign	Sometimes (5–29%)
Upper motor neuron dysfunction	Sometimes (5–29%)
Wide based walk	Sometimes (5–29%)
CNS demyelination	Not recorded
Peripheral demyelination	Not recorded

Laboratory abnormality

Trait	How often it is seen
Abnormal circulating apolipoprotein concentration	Very often (80–99%)
Vitamin E deficiency	Very often (80–99%)
Decreased circulating cholesterol level	Often (30–79%)
Decreased circulating high-density lipoprotein cholesterol	Often (30–79%)
Decreased circulating LDL-C concentration	Often (30–79%)
Deficient in vitamin D	Often (30–79%)
High blood bilirubin levels	Often (30–79%)
Low albumin	Often (30–79%)
Low blood triglyceride levels	Often (30–79%)
Vitamin A deficiency	Often (30–79%)
Fatty infiltration of liver	Sometimes (5–29%)
High liver enzymes	Sometimes (5–29%)
Low ESR	Sometimes (5–29%)
Abetalipoproteinemia	Not recorded

Abnormality of the eye

Trait	How often it is seen
Abnormal color vision	Often (30–79%)
Abnormal retinal pigmentation	Often (30–79%)
Difficulties with night vision	Often (30–79%)
Progressive loss of vision	Often (30–79%)
Blind spot	Sometimes (5–29%)
Fundus hypopigmentation	Sometimes (5–29%)
Rod-cone dystrophy	Sometimes (5–29%)
Blindness	Rarely (1–4%)
Corneal ulceration	Rarely (1–4%)
Drooping upper eyelid	Rarely (1–4%)
Eye muscle paralysis	Rarely (1–4%)
Noninflammatory retina disease	Not recorded
Retina degeneration	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Fat in feces	Very often (80–99%)
Fat malabsorption	Very often (80–99%)
Chronic diarrhea	Often (30–79%)
Enlarged liver	Sometimes (5–29%)
Vomiting	Sometimes (5–29%)
Hepatic fibrosis	Rarely (1–4%)
Scar tissue replaces healthy tissue in the liver	Rarely (1–4%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Acanthocytosis	Very often (80–99%)
Increased immature red blood cells	Often (30–79%)
Low number of red blood cells or hemoglobin	Often (30–79%)
Prolonged prothrombin time	Sometimes (5–29%)
Bleeding tendency	Rarely (1–4%)

Abnormality of limbs

Trait	How often it is seen
Club feet	Sometimes (5–29%)
Distal lower limb muscle weakness	Sometimes (5–29%)
High-arched foot	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Kyphoscoliosis	Sometimes (5–29%)
Muscle tissue disease	Sometimes (5–29%)
Osteopenia	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Cardiac failure	Rarely (1–4%)
Enlarged heart	Rarely (1–4%)

Abnormality of head or neck

Trait	How often it is seen
Dry eye syndrome	Rarely (1–4%)

Abnormality of the endocrine system

Trait	How often it is seen
Underactive thyroid	Rarely (1–4%)

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory failure	Rarely (1–4%)

Constitutional symptom

Trait	How often it is seen
Muscle ache	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Often (30–79%)

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 MTTP and how often each is seen. Find out more at hpo.jax.org.

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