Traits

Traits linked to TBC1D32

TBC1 domain family member 32

The Human Phenotype Ontology links 103 traits to TBC1D32, by body system: features seen in people with one of the gene's rare conditions.

TBC1D32

Abnormality of head or neck

Trait	How often it is seen
Broad forehead	Always
Cleft lip	Always
Dandy-Walker malformation	Always
Depressed nasal bridge	Always
High, narrow palate	Always
Nasal tip, upturned	Always
Tongue tied	Always
Wider-than-typical soft spot of skull	Always
Abnormal sella turcica morphology	Often (30–79%)
Midface retrusion	Often (30–79%)
Abnormally small head	Sometimes (5–29%)
Absent nose	Sometimes (5–29%)
Big calvaria	Sometimes (5–29%)
Blockage of the rear opening of the nasal cavity	Sometimes (5–29%)
Little lower jaw	Sometimes (5–29%)
Long philtrum	Sometimes (5–29%)
Midline facial cleft	Sometimes (5–29%)
Mono nostril	Sometimes (5–29%)
Only one upper front tooth	Sometimes (5–29%)
Prominent nose	Sometimes (5–29%)
Thin red part of the upper lip	Sometimes (5–29%)
Abnormal dentition	Not recorded
Accessory oral frenulum	Not recorded
Broad nasal tip	Not recorded
Central cleft upper lip	Not recorded
Cleft nasal tip	Not recorded
Cleft palate	Not recorded
Corners of eye widely separated	Not recorded
High palate	Not recorded

Abnormality of the eye

Trait	How often it is seen
Cerebral visual impairment	Always
Decreased clarity of vision	Always
Difficulties with night vision	Always
Hypoautofluorescent retinal lesion	Always
Hypoplastic optic chiasm	Always
Limited peripheral vision	Always
Optic disc pallor	Always
Spicular pigmentation of the retina	Always
Undetectable light- and dark-adapted electroretinogram	Always
Wide-set eyes	Always
Moderate myopia	Often (30–79%)
Perifoveal ring of hyperautofluorescence	Often (30–79%)
Severe near sightedness	Often (30–79%)
Abnormally small eyeball	Sometimes (5–29%)
Absence of eyeballs	Sometimes (5–29%)
Cross-eyed	Sometimes (5–29%)
Cyclops eye	Sometimes (5–29%)
Deeply set eye	Sometimes (5–29%)
Different colored eyes	Sometimes (5–29%)
Optic nerve aplasia	Sometimes (5–29%)
Retinal dysplasia	Sometimes (5–29%)
Hole in the back of the eye	Not recorded

Abnormality of limbs

Trait	How often it is seen
Club feet	Always
Disproportionately short upper portion of limb	Always
Extra little finger	Always
Short fingers or toes	Always
Small hand	Always
Gap between 1st and 2nd toes	Often (30–79%)
Underdeveloped inner large forearm bone	Often (30–79%)
Postaxial polydactyly	Sometimes (5–29%)
Rocker bottom foot	Sometimes (5–29%)
Short digit	Sometimes (5–29%)
Webbed 2nd-5th toes	Sometimes (5–29%)
Webbed skin of 2nd-3rd toes	Sometimes (5–29%)
Extra finger	Not recorded
Fused toes	Not recorded
Short shinbone	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Agenesis of corpus callosum	Always
Delayed speech and language development	Always
Dysgenesis of the cerebellar vermis	Always
Global developmental delay	Always
Lobar holoprosencephaly	Always
Partial agenesis of the corpus callosum	Always
Abnormal cerebellar vermis morphology	Often (30–79%)
Anencephaly	Sometimes (5–29%)
Dysgenesis of the hypothalamus	Sometimes (5–29%)
Fusion of the left and right thalami	Sometimes (5–29%)
Holoprosencephaly	Sometimes (5–29%)
Ventriculomegaly	Sometimes (5–29%)
Brain degeneration	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
All organs on wrong side of body	Always
Hole in heart wall separating two lower heart chambers	Always
Narrowing of blood vessels in back of eye	Always
Hole in center of heart	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased response to growth hormone stimulation test	Always
Underdeveloped pituitary gland	Always
Ectopic anterior pituitary gland	Sometimes (5–29%)
Small adrenal glands	Sometimes (5–29%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Always
Short fetal thigh bone length	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Intestinal malrotation	Often (30–79%)
Omphalocele	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Glue ear	Always
Low-set ears	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Short penis	Always
Small kidneys	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Short long bone	Sometimes (5–29%)
Permanent flexion of the finger or toe	Not recorded

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Sometimes (5–29%)
Short stature	Not recorded

Abnormal tissue mass

Trait	How often it is seen
Hamartoma	Not recorded

Abnormality of the immune system

Trait	How often it is seen
Recurrent aspiration pneumonia	Not recorded

Abnormality of the integument

Trait	How often it is seen
Milk spot	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Hypoplasia of the epiglottis	Not recorded

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 TBC1D32 and how often each is seen. Find out more at hpo.jax.org.

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