Traits

Traits linked to IL6ST

interleukin 6 cytokine family signal transducer

The Human Phenotype Ontology links 80 traits to IL6ST, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of head or neck

Trait	How often it is seen
Abnormally large tongue	Always
Big calvaria	Always
Big lower jaw	Always
Deep philtrum	Always
Deformity of the skull	Always
Dental crowding	Always
Depressed nasal bridge	Always
Downward slanting of the opening between the eyelids	Always
High palate	Always
Nasal tip, upturned	Always
Prominent forehead	Always
Scaphocephaly	Always
Short neck	Always
Delayed loss of baby teeth	Very often (80–99%)
Recurrent colds	Often (30–79%)
Enlarged cisterna magna	Sometimes (5–29%)
Extra teeth	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Death of bone due to decreased blood supply	Always
Disease of the joints	Always
Pigeon chest	Always
Scoliosis	Always
Thoracolumbar scoliosis	Always
Double-Jointed	Often (30–79%)
Increased susceptibility to fractures	Often (30–79%)
Permanent flexion of the finger or toe	Often (30–79%)
Short long bone	Sometimes (5–29%)
Small chest	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Asthma	Always
Eczema	Always
Food allergy	Always
Recurrent pneumonia	Always
Recurrent respiratory infections	Always
Baby eczema	Often (30–79%)
Recurrent skin infections	Often (30–79%)
Skin abscess	Often (30–79%)
Recurrent mucocutaneous candidiasis	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
High blood eosinophil count	Always
Microcytic anemia	Always
Low platelet count	Often (30–79%)
Decreased blood lymphocyte number	Sometimes (5–29%)
Disseminated intravascular coagulation	Sometimes (5–29%)
Low blood neutrophil count	Sometimes (5–29%)
Reduced total natural killer cell count	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Clubbing of fingers and toes	Always
Hip dislocation	Always
Joint contracture of the hand	Always
Outward turned elbows	Always
Bowing of the long bones	Very often (80–99%)
Club feet	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased circulating antibody level	Always
Increased circulating IgE concentration	Always
Decreased circulating IgA concentration	Often (30–79%)
Decreased circulating IgG concentration	Sometimes (5–29%)
Decreased circulating IgM concentration	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Enlarged liver and spleen	Always
Mitral regurgitation	Always
Swollen lymph nodes	Always
Cardiac failure	Often (30–79%)
Increased blood pressure in blood vessels of lungs	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Permanent enlargement of the airways of the lungs	Always
Breathing difficulties	Often (30–79%)
Pulmonary pneumatocele	Often (30–79%)
Bronchomalacia	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Always
Low-set ears	Always
Recurrent middle ear infection	Always

Abnormality of the digestive system

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

Abnormality of the eye

Trait	How often it is seen
Corneal inflammation	Always
Wide-set eyes	Always

Abnormality of the nervous system

Trait	How often it is seen
Neurodevelopmental delay	Always
Motor delay	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Always
Short stature	Always

Laboratory abnormality

Trait	How often it is seen
Elevated circulating C-reactive protein concentration	Always
Elevated circulating serum amyloid A concentration	Always

Abnormal tissue mass

Trait	How often it is seen
Fibroma	Always

Abnormality of prenatal development or birth

Trait	How often it is seen
Delayed umbilical cord separation	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Underactive thyroid	Always

Abnormality of the integument

Trait	How often it is seen
Excessive hair growth	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 IL6ST and how often each is seen. Find out more at hpo.jax.org.

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