Traits

Traits linked to RAB3GAP2

RAB3 GTPase activating non-catalytic protein subunit 2

The Human Phenotype Ontology links 137 traits to RAB3GAP2, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Absent speech development	Always
Clonus	Always
Delayed ability to sit	Always
Delayed ability to walk	Always
Delayed speech and language development	Always
Diminished deep tendon reflex	Always
Enlarged sylvian cistern	Always
Generalized brain degeneration	Always
Global developmental delay	Always
Intellectual disability, severe	Always
More grooves in brain	Always
Periventricular white matter hyperintensities	Always
Severe global developmental delay	Always
Underdevelopment of part of brain called corpus callosum	Always
Aplasia/Hypoplasia of the corpus callosum	Very often (80–99%)
Fewer and broader ridges in brain	Very often (80–99%)
Fewer or absent grooves in brain	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Abnormal myelination	Often (30–79%)
Abnormality of movement	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Aplasia/Hypoplasia of the cerebellar vermis	Often (30–79%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Fluid-filled sac located in membrane surrounding brain or spinal cord	Often (30–79%)
Hand tremor	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Abnormality of the cerebellum	Sometimes (5–29%)
Cerebellar vermis hypoplasia	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Peripheral neuropathy	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Always
Broad head shape	Always
Decreased size of maxilla	Always
Long philtrum	Always
Low hairline at back of neck	Always
Prominent nasal bridge	Always
Short nose	Always
Short philtrum	Always
Drooping lower lip	Very often (80–99%)
Grooved tongue	Very often (80–99%)
High palate	Very often (80–99%)
Midface retrusion	Very often (80–99%)
Nasal tip, upturned	Very often (80–99%)
Wide nasal bridge	Very often (80–99%)
Zygomatic flattening	Very often (80–99%)
Abnormal dental position	Often (30–79%)
Depressed nasal bridge	Often (30–79%)
Little lower jaw	Often (30–79%)
Low frontal hairline	Often (30–79%)
Broad nasal tip	Not recorded
Development of small head that was not present at birth	Not recorded
Downward slanting of the opening between the eyelids	Not recorded
Eye folds	Not recorded

Abnormality of limbs

Trait	How often it is seen
Avascular necrosis of the capital femoral epiphysis	Always
Clinodactyly of the 5th toe	Always
Curvature of 4th toe	Always
Dropped arches	Always
Increased mobility in finger joint	Always
Talipes valgus	Always
Abnormality of the hand	Often (30–79%)
Abnormality of the outermost finger bone	Often (30–79%)
Broad femoral neck	Often (30–79%)
Finger bends toward pinky	Often (30–79%)
Osteopathia striata	Often (30–79%)
Broad fingertip	Not recorded
Club feet	Not recorded
Front half of foot turns inward	Not recorded
Overlapping toe	Not recorded
Short finger bones	Not recorded
Short palm	Not recorded
Short toe	Not recorded
Shortened long bone of hand	Not recorded
Slender ulna	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Always
Spastic diplegia	Always
Thoracic scoliosis	Always
Involuntary muscle stiffness, contraction, or spasm	Very often (80–99%)
Joint stiffness	Very often (80–99%)
Hunched back	Often (30–79%)
Lower limb spasticity	Often (30–79%)
Progressive spastic paraplegia	Often (30–79%)
Prominent swayback	Often (30–79%)
Scoliosis	Often (30–79%)
Spastic dysarthria	Often (30–79%)
Double-Jointed	Not recorded
Excessive inward curvature of lower spine	Not recorded
Flexed joint that cannot be straightened	Not recorded
Funnel chest	Not recorded
Low muscle tone in trunk	Not recorded
Pigeon chest	Not recorded

Abnormality of the eye

Trait	How often it is seen
Abnormally small eyeball	Always
Clouding of the lens of the eye	Always
Clouding of the lens of the eye at birth	Always
Deeply set eye	Always
Cerebral visual impairment	Very often (80–99%)
Cornea of eye less than 10mm in diameter	Very often (80–99%)
Optic atrophy	Very often (80–99%)
Abnormal retinal pigmentation	Often (30–79%)
Abnormality of visual evoked potentials	Often (30–79%)
Abnormally close eyes	Often (30–79%)
Cross-eyed	Often (30–79%)
Hole in the back of the eye	Sometimes (5–29%)
Undetectable visual evoked potentials	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Short penis	Always
Undescended testes	Always
Small clitoris	Often (30–79%)
Underdeveloped inner lips	Often (30–79%)
Underdeveloped penis	Often (30–79%)
Abnormal localisation of kidneys	Sometimes (5–29%)
Hydronephrosis	Sometimes (5–29%)
Small labia majora	Not recorded
Smaller than typical growth of scrotum	Not recorded

Abnormality of the ear

Trait	How often it is seen
Asymmetric ears	Always
Large ears	Always
Low-set ears	Always
Ears rotated toward back of head	Often (30–79%)
Hearing impairment	Often (30–79%)
Abnormal antihelix morphology	Sometimes (5–29%)
Prominent antitragus	Not recorded

Abnormality of the integument

Trait	How often it is seen
Abnormal fingerprints	Very often (80–99%)
Prematurely aged appearance	Very often (80–99%)
Abnormality of the toenail	Often (30–79%)
Excessive hairiness over body	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Heart stops beating	Often (30–79%)
Cardiac failure	Not recorded
Disease of the heart muscle	Not recorded

Growth abnormality

Trait	How often it is seen
Short stature	Very often (80–99%)
Prenatal growth deficiency	Often (30–79%)
Growth delay as children	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties in infancy	Always
Inguinal hernia	Often (30–79%)

Abnormality of the endocrine system

Trait	How often it is seen
Delayed puberty	Very often (80–99%)
Hypogonadotropic hypogonadism	Very often (80–99%)

Abnormality of the breast

Trait	How often it is seen
Prominent nipples	Not recorded

Abnormality of the immune system

Trait	How often it is seen
Recurrent respiratory infections	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Floppy windpipe	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 RAB3GAP2 and how often each is seen. Find out more at hpo.jax.org.

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