Traits

Traits linked to FOXN1

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The Human Phenotype Ontology links 56 traits to FOXN1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the immune system

Trait	How often it is seen
Recurrent viral infections	Always
Cellular immunodeficiency	Very often (80–99%)
Decreased immune function	Very often (80–99%)
Recurrent infections	Very often (80–99%)
Severe T-cell immunodeficiency	Very often (80–99%)
Autoimmunity	Often (30–79%)
Opportunistic infection	Often (30–79%)
Pneumonia	Often (30–79%)
Recurrent bacterial infections	Often (30–79%)
Severe infection	Often (30–79%)
Severe viral infection	Often (30–79%)
Baby eczema	Sometimes (5–29%)
Combined immunodeficiency	Sometimes (5–29%)
Eczema	Sometimes (5–29%)
Infection in blood stream	Sometimes (5–29%)
Invasive fungal infection	Sometimes (5–29%)
Meningitis	Sometimes (5–29%)
Recurrent Candida infection	Sometimes (5–29%)
Recurrent Staphylococcus aureus infection	Sometimes (5–29%)
Recurrent streptococcus pneumoniae infections	Sometimes (5–29%)
Pus-filled lesion	Not recorded
Recurrent infections in bronchi and lungs	Not recorded
Recurrent pneumonia	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Abnormally low T cell receptor excision circle level	Always
Low T cell count	Always
Decreased naive T cell proportion	Very often (80–99%)
Coombs-positive hemolytic anemia	Sometimes (5–29%)
Oligoclonal T cell expansion	Sometimes (5–29%)
Decreased blood lymphocyte number	Not recorded
Decreased total CD4+ T cell proportion	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Recurrent infection of the gastrointestinal tract	Often (30–79%)
Atypical or prolonged liver inflammation	Sometimes (5–29%)
Diarrhea	Sometimes (5–29%)
Malabsorption	Sometimes (5–29%)
Chronic diarrhea	Not recorded

Abnormality of the integument

Trait	How often it is seen
Congenital alopecia totalis	Very often (80–99%)
Grooved nails	Very often (80–99%)
Nail pits	Very often (80–99%)
Poor nail formation	Often (30–79%)
Hair loss	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Chronic oral thrush	Sometimes (5–29%)
Sinus disease	Sometimes (5–29%)
Recurrent colds	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Absent thymus	Always
Swollen lymph nodes	Sometimes (5–29%)
Enlarged liver and spleen	Not recorded

Abnormal cellular phenotype

Trait	How often it is seen
Decreased mitogen-induced T-cell proliferation	Very often (80–99%)
Reduced delayed hypersensitivity	Not recorded

Abnormality of the endocrine system

Trait	How often it is seen
Thyroid gland inflammation	Sometimes (5–29%)
Underactive thyroid	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Emphysema	Not recorded
Permanent enlargement of the airways of the lungs	Not recorded

Abnormality of the ear

Trait	How often it is seen
Chronic infections of the middle ear	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Frequent urinary tract infections	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Hypocalcemic tetany	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Faltering weight	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 FOXN1 and how often each is seen. Find out more at hpo.jax.org.

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