Traits

Traits linked to TBX1

T-box transcription factor 1

The Human Phenotype Ontology links 216 traits to TBX1, 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
Velopharyngeal incompetence	Always
Abnormal facial shape	Very often (80–99%)
Abnormal of nasal shape	Very often (80–99%)
Broad forehead	Very often (80–99%)
Bulbous nose	Very often (80–99%)
Cleft palate	Very often (80–99%)
Corners of eye widely separated	Very often (80–99%)
Eye folds	Very often (80–99%)
Flattening of the skull base	Very often (80–99%)
Prominent nasal bridge	Very often (80–99%)
Upward slanting of the opening between the eyelids	Very often (80–99%)
Wide nasal bridge	Very often (80–99%)
Abnormal dentition	Often (30–79%)
Abnormality of the eyelid	Often (30–79%)
Abnormality of the skull	Often (30–79%)
Decreased volume of lip	Often (30–79%)
Dental cavities	Often (30–79%)
Downward slanting of the opening between the eyelids	Often (30–79%)
Flat nose	Often (30–79%)
Flattened bony protrusion above eyes	Often (30–79%)
High forehead	Often (30–79%)
Long face	Often (30–79%)
Long philtrum	Often (30–79%)
Long, narrow head	Often (30–79%)
Midface retrusion	Often (30–79%)
Narrow face	Often (30–79%)
Pit in front of the ear	Often (30–79%)
Short neck	Often (30–79%)
Submucous cleft hard palate	Often (30–79%)
Zygomatic flattening	Often (30–79%)
Abnormal tooth enamel	Sometimes (5–29%)
Abnormally small head	Sometimes (5–29%)
Blockage of the rear opening of the nasal cavity	Sometimes (5–29%)
Drooling	Sometimes (5–29%)
Little lower jaw	Sometimes (5–29%)
Multiple suture craniosynostosis	Sometimes (5–29%)
Narrow mouth	Sometimes (5–29%)
Recurrent sinus disease	Sometimes (5–29%)
Retinal arteriolar tortuosity	Sometimes (5–29%)
Short philtrum	Sometimes (5–29%)
Smooth philtrum	Sometimes (5–29%)
Tall shaped head	Sometimes (5–29%)
Wide nose	Sometimes (5–29%)
Bifid uvula	Not recorded
High palate	Not recorded
High, narrow palate	Not recorded
Narrow eyelid opening	Not recorded
Narrow opening between the eyelids	Not recorded
Open mouth	Not recorded
Pierre-Robin sequence	Not recorded
Receding chin	Not recorded
Short opening between the eyelids	Not recorded
Underdeveloped tissue around nostril	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal aortic arch morphology	Very often (80–99%)
Abnormal cardiovascular system morphology	Very often (80–99%)
Abnormal pulmonary valve morphology	Very often (80–99%)
An opening in the wall separating the top two chambers of the heart	Very often (80–99%)
Hole in heart wall separating two lower heart chambers	Very often (80–99%)
Small thymus	Very often (80–99%)
Tetralogy of Fallot	Very often (80–99%)
Truncus arteriosus	Very often (80–99%)
Abnormality of the tonsils	Often (30–79%)
Abnormal aortic valve morphology	Sometimes (5–29%)
Absent/small thymus	Sometimes (5–29%)
Double aortic arch	Sometimes (5–29%)
Hypertensive crisis	Sometimes (5–29%)
Increased spleen size	Sometimes (5–29%)
Interrupted aortic arch	Sometimes (5–29%)
Patent ductus arteriosus	Sometimes (5–29%)
Pulmonary artery atresia	Sometimes (5–29%)
Transposition of the great arteries	Sometimes (5–29%)
Tricuspid atresia	Sometimes (5–29%)
Underdeveloped left heart	Sometimes (5–29%)
Varicose veins	Sometimes (5–29%)
Abnormality of the thymus	Not recorded
Complete atrioventricular canal defect	Not recorded
Double outlet right ventricle	Not recorded
Narrowing of aorta	Not recorded
Retinal vascular tortuosity	Not recorded
Right aortic arch with mirror image branching	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Difficulty finding words	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Abnormal speech pattern	Often (30–79%)
Anxiety	Often (30–79%)
Attention deficit	Often (30–79%)
Delayed speech and language development	Often (30–79%)
Epilepsy	Often (30–79%)
Global developmental delay	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
Meningocele	Often (30–79%)
Specific learning disability	Often (30–79%)
Arrhinencephaly	Sometimes (5–29%)
Autism	Sometimes (5–29%)
Behavioral abnormality	Sometimes (5–29%)
Bipolar disorder	Sometimes (5–29%)
Depression	Sometimes (5–29%)
Obsessive compulsive behavior	Sometimes (5–29%)
Parkinsonism	Sometimes (5–29%)
Repetitive movements	Sometimes (5–29%)
Schizophrenia	Sometimes (5–29%)
Split spine	Sometimes (5–29%)
Too much cerebrospinal fluid in the brain	Sometimes (5–29%)
Weakness of one side of body	Sometimes (5–29%)
Aggressive behavior	Not recorded
Can't control feelings	Not recorded
Paranoia	Not recorded

Abnormality of the eye

Trait	How often it is seen
Bulging eye	Often (30–79%)
Drooping upper eyelid	Often (30–79%)
New blood vessel formation in cornea	Often (30–79%)
Posterior embryotoxon	Often (30–79%)
Wide-set eyes	Often (30–79%)
Abnormally small eyeball	Sometimes (5–29%)
Clouding of the lens of the eye	Sometimes (5–29%)
Cross-eyed	Sometimes (5–29%)
Glaucoma	Sometimes (5–29%)
Optic atrophy	Sometimes (5–29%)
Accommodative esotropia	Not recorded
Esophoria	Not recorded
Hardening of skin and connective tissue	Not recorded
Inward turning cross eyed	Not recorded
Lazy eye	Not recorded
Outward facing eye ball	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Small kidneys	Often (30–79%)
Undescended testes	Often (30–79%)
Abnormality of the uterus	Sometimes (5–29%)
Absent kidney on one side	Sometimes (5–29%)
Displacement of the urethral meatus	Sometimes (5–29%)
Hydrocele testis	Sometimes (5–29%)
Hydronephrosis	Sometimes (5–29%)
Hypospadias	Sometimes (5–29%)
Multiple kidney cysts	Sometimes (5–29%)
Narrowing of the urethra	Sometimes (5–29%)
Ovarian cyst	Sometimes (5–29%)
Polycystic kidney dysplasia	Sometimes (5–29%)
Renal failure	Sometimes (5–29%)
Vesicoureteral reflux	Sometimes (5–29%)
Renal dysplasia	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Anorectal anomaly	Often (30–79%)
Constipation	Often (30–79%)
Absent anus	Sometimes (5–29%)
Acid reflux	Sometimes (5–29%)
Enlarged colon lacking nerve cells	Sometimes (5–29%)
Feeding difficulties in infancy	Sometimes (5–29%)
Gallstones	Sometimes (5–29%)
Inguinal hernia	Sometimes (5–29%)
Intestinal malrotation	Sometimes (5–29%)
Loss of bowel control	Sometimes (5–29%)
Umbilical hernia	Sometimes (5–29%)
Femoral hernia	Not recorded

Abnormality of limbs

Trait	How often it is seen
Curvature of little finger	Very often (80–99%)
Short fingers or toes	Very often (80–99%)
Long slender fingers	Often (30–79%)
Club feet	Sometimes (5–29%)
Dislocated kneecap	Sometimes (5–29%)
Duplication of bones of the toes	Sometimes (5–29%)
Extra finger	Sometimes (5–29%)
Talipes	Sometimes (5–29%)
Abnormality of the hand	Not recorded
Broad big toe	Not recorded
Postaxial polydactyly	Not recorded

Abnormality of the ear

Trait	How often it is seen
Conductive deafness	Very often (80–99%)
Low-set ears	Very often (80–99%)
Chronic infections of the middle ear	Often (30–79%)
Hearing impairment	Often (30–79%)
Overfolded ears	Often (30–79%)
Recurrent middle ear infection	Often (30–79%)
Small earlobe	Often (30–79%)
Earlobe crease	Sometimes (5–29%)
Abnormality of the ear	Not recorded
Abnormality of the middle ear	Not recorded

Abnormality of the immune system

Trait	How often it is seen
Decreased immune function	Very often (80–99%)
Acne	Often (30–79%)
Recurrent pneumonia	Often (30–79%)
Seborrheic dermatitis	Often (30–79%)
Abnormality of immune system physiology	Sometimes (5–29%)
Asthma	Sometimes (5–29%)
Autoimmunity	Sometimes (5–29%)
Recurrent infections	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Very often (80–99%)
Intermittent involuntary muscle spasm	Often (30–79%)
Scoliosis	Often (30–79%)
Abnormality of the chest	Sometimes (5–29%)
Arthritis	Sometimes (5–29%)
Double-Jointed	Sometimes (5–29%)
Intervertebral disk degeneration	Sometimes (5–29%)
Pilonidal sinus	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Abnormality of the pharynx	Very often (80–99%)
Abnormal lung lobation	Sometimes (5–29%)
Chronic pulmonary obstruction	Sometimes (5–29%)
Partial or complete collapse of part or entire lung	Sometimes (5–29%)
Softening of voice box tissue	Sometimes (5–29%)
Unilateral primary pulmonary dysgenesis	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Blood spots	Sometimes (5–29%)
Gastrointestinal bleeding	Sometimes (5–29%)
Low number of red blood cells or hemoglobin	Sometimes (5–29%)
Low platelet count	Sometimes (5–29%)
Platelet abnormalities	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased parathyroid hormone secretion	Often (30–79%)
Overactive thyroid	Sometimes (5–29%)
Underactive thyroid	Sometimes (5–29%)
Parathyroid agenesis	Not recorded
Small parathyroid glands	Not recorded

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Very often (80–99%)
Obesity	Often (30–79%)
Short stature	Often (30–79%)
Faltering weight	Sometimes (5–29%)
Growth delay	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Low blood calcium levels	Often (30–79%)
Fatty infiltration of liver	Sometimes (5–29%)
Decreased circulating parathyroid hormone level	Not recorded
Laboratory abnormality	Not recorded

Abnormal cellular phenotype

Trait	How often it is seen
Impaired T cell function	Often (30–79%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Patchy loss of skin color	Sometimes (5–29%)

Abnormality of the voice

Trait	How often it is seen
Nasal speech	Very often (80–99%)

Constitutional symptom

Trait	How often it is seen
Muscle ache	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 TBX1 and how often each is seen. Find out more at hpo.jax.org.

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