Traits

Traits linked to FAT4

FAT atypical cadherin 4

The Human Phenotype Ontology links 134 traits to FAT4, 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
Abnormal facial shape	Always
Depressed nasal bridge	Always
Eye folds	Always
Full cheeks	Always
High frontal hairline	Always
Irregular teeth	Always
Narrow eyelid opening	Always
Prominent forehead	Always
Abnormality of dental shape	Very often (80–99%)
Decreased number of teeth	Very often (80–99%)
Delayed eruption of teeth	Very often (80–99%)
Extra teeth	Very often (80–99%)
Flat face	Very often (80–99%)
Wide nasal bridge	Very often (80–99%)
Abnormality of lining of mouth	Often (30–79%)
Broad forehead	Often (30–79%)
Gum enlargement	Often (30–79%)
Little lower jaw	Often (30–79%)
Narrow mouth	Often (30–79%)
Narrow opening between the eyelids	Often (30–79%)
Wide fontanelles	Often (30–79%)
Abnormally small head	Sometimes (5–29%)
Bilateral choanal atresia/stenosis	Sometimes (5–29%)
Decreased size of maxilla	Sometimes (5–29%)
Deformity of the skull	Sometimes (5–29%)
Receding chin	Sometimes (5–29%)
Short philtrum	Sometimes (5–29%)
Bad bite	Not recorded
Downturned corners of mouth	Not recorded
High palate	Not recorded
Large cranial suture	Not recorded
Midface retrusion	Not recorded
Narrow forehead	Not recorded
Short opening between the eyelids	Not recorded
Tented mouth	Not recorded
Wider-than-typical soft spot of skull	Not recorded
Zygomatic flattening	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Global developmental delay	Always
Underdevelopment of part of brain called corpus callosum	Always
Intellectual disability	Very often (80–99%)
Epilepsy	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
IQ between 34 and 49	Often (30–79%)
Periventricular nodular heterotopia	Often (30–79%)
Agenesis of corpus callosum	Sometimes (5–29%)
Ataxia	Sometimes (5–29%)
Benign neoplasm of the central nervous system	Sometimes (5–29%)
Cerebellar vermis hypoplasia	Sometimes (5–29%)
Dysplastic corpus callosum	Sometimes (5–29%)
Fewer and broader ridges in brain	Sometimes (5–29%)
Gray matter heterotopia	Sometimes (5–29%)
Intellectual disability, severe	Sometimes (5–29%)
Self-injurious behavior	Sometimes (5–29%)
Ventriculomegaly	Sometimes (5–29%)
Subcortical band heterotopia	Not recorded

Abnormality of limbs

Trait	How often it is seen
Club feet	Always
Partial hip dislocation	Always
Ulnar deviation of the hand	Always
Webbed fingers	Always
Webbed skin of toes	Always
Webbed fingers or toes	Often (30–79%)
Abnormal feet structure	Sometimes (5–29%)
Finger syndactyly	Sometimes (5–29%)
Permanent flexion of the finger	Sometimes (5–29%)
Curvature of digit	Not recorded
Short 4th long bone of foot	Not recorded
Shortened 4th long bone of hand	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Always
Decreased muscle tone in infant	Very often (80–99%)
Permanent flexion of the finger or toe	Very often (80–99%)
Narrow chest	Often (30–79%)
Osteopenia	Often (30–79%)
Human tail	Sometimes (5–29%)
Osteoporosis	Sometimes (5–29%)
Abnormal skeletal development	Not recorded
Double-Jointed	Not recorded
Scoliosis	Not recorded
Short collarbone	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Lymphangioma	Very often (80–99%)
Increased spleen size	Often (30–79%)
Intestinal lymphangiectasia	Often (30–79%)
Swollen lymph nodes	Often (30–79%)
Abnormality of the heart	Sometimes (5–29%)
Arteriovenous malformation	Sometimes (5–29%)
Fluid around heart	Sometimes (5–29%)
Narrowing of pulmonic valve	Sometimes (5–29%)
Pulmonary lymphangiectasia	Sometimes (5–29%)
Pericardial lymphangiectasia	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Anteriorly placed anus	Always
Feeding difficulties	Always
Inguinal hernia	Always
Feeding difficulties in infancy	Very often (80–99%)
Malabsorption	Very often (80–99%)
Accumulation of fluid in the abdomen	Often (30–79%)
Gastrostomy tube feeding in infancy	Often (30–79%)
Narrowing of anal opening	Sometimes (5–29%)
Pyloric stenosis	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Always
Narrow ear canal	Always
Small ears	Always
Abnormally shaped ears	Very often (80–99%)
Low-set ears	Very often (80–99%)
Conductive deafness	Often (30–79%)
Absent ear canal	Not recorded
Sensorineural hearing impairment	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Cleft of scrotum	Always
Short penis	Always
Small kidneys	Always
Undescended testes	Always
Abnormal kidney location	Sometimes (5–29%)
Horseshoe kidney	Sometimes (5–29%)
Hypospadias	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Swelling caused by excess lymph fluid under skin	Very often (80–99%)
Chylothorax	Sometimes (5–29%)
Hydrops fetalis	Sometimes (5–29%)
Low blood calcium levels	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Always
Glaucoma	Often (30–79%)
Drooping upper eyelid	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Abnormal tracheal morphology	Often (30–79%)
Floppy windpipe	Sometimes (5–29%)
Respiratory function loss	Sometimes (5–29%)

Growth abnormality

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

Abnormality of the immune system

Trait	How often it is seen
Erysipelas	Often (30–79%)
Recurrent respiratory infections	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Spinal dimple	Always
Limited armpit hair	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased circulating antibody level	Very often (80–99%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Decreased blood lymphocyte number	Very often (80–99%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Only one artery in umbilical cord instead of two	Always

Abnormality of the breast

Trait	How often it is seen
Small nipples	Always

Abnormality of the endocrine system

Trait	How often it is seen
Absence of pubertal development	Sometimes (5–29%)

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 FAT4 and how often each is seen. Find out more at hpo.jax.org.

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