Traits

Traits linked to RBSN

rabenosyn, RAB effector

The Human Phenotype Ontology links 102 traits to RBSN, by body system: features seen in people with one of the gene's rare conditions.

RBSN

Abnormality of head or neck

Trait	How often it is seen
Abnormal facial shape	Always
Decreased size of tooth	Always
Dental cavities	Always
Development of small head that was not present at birth	Always
Full lower lip	Always
Highly arched eyebrow	Always
Low hanging columella	Always
Narrow opening between the eyelids	Always
Narrow palate	Always
Prominent nasal bridge	Always
Prominent nose	Always
Short nose	Always
Underdeveloped tissue around nostril	Always
Bulbous nose	Often (30–79%)
Depressed nasal tip	Often (30–79%)
Downward slanting of the opening between the eyelids	Often (30–79%)
Eye folds	Often (30–79%)
High palate	Often (30–79%)
Narrow forehead	Often (30–79%)
Narrow mouth	Often (30–79%)
Open mouth	Often (30–79%)
Prominent metopic ridge	Often (30–79%)
Sloping forehead	Often (30–79%)
Small retruded chin	Often (30–79%)
Upward slanting of the opening between the eyelids	Often (30–79%)

Abnormality of the nervous system

Trait	How often it is seen
Absent speech development	Always
Delayed ability to walk	Always
Delayed speech and language development	Always
Global developmental delay	Always
Inability to walk	Always
Infantile spasms	Always
Intellectual disability, severe	Always
Motor delay	Always
Thin corpus callosum	Always
Degeneration of cerebrum	Often (30–79%)
Delayed CNS myelination	Often (30–79%)
Increased reflexes	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
Intention tremor	Often (30–79%)
IQ between 34 and 49	Often (30–79%)

Abnormality of the eye

Trait	How often it is seen
Abnormally small eyeball	Always
Blue outer white part of eyeball	Always
Deeply set eye	Always
Drooping upper eyelid	Always
Hypoplastic optic chiasm	Always
Optic nerve hypoplasia	Always
Absent iris	Often (30–79%)
Cat eye	Often (30–79%)
Cornea of eye less than 10mm in diameter	Often (30–79%)
Optic nerve aplasia	Often (30–79%)
Optic nerve dysplasia	Often (30–79%)
Underdeveloped iris	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Circulating nucleated red blood cells	Always
Decreased blood lymphocyte number	Always
Decreased hemoglobin concentration	Always
Extramedullary hematopoiesis	Always
Low blood neutrophil count	Always
Low number of red blood cells or hemoglobin	Always
Bone marrow hypercellularity	Often (30–79%)
Low platelet count	Often (30–79%)
Myelofibrosis	Often (30–79%)

Abnormality of limbs

Trait	How often it is seen
Coxa valga	Always
Dropped arches	Always
Lower limb hypertonia	Always
Thickening of shaft or central part of long bones	Always
Upper limb hypertonia	Always
Curvature of digit	Often (30–79%)
Femur fracture	Often (30–79%)
Tapered finger	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormal formation of the hip	Always
Cone-shaped end part of bone	Always
Delayed bone maturation	Always
Low muscle tone	Always
Muscle degeneration	Always
Muscle weakness	Always
Osteopenia	Always
Poor head control	Always

Abnormality of the cardiovascular system

Trait	How often it is seen
Foam cells	Always
Accessory spleen	Often (30–79%)
Enlarged heart	Often (30–79%)
Increased spleen size	Often (30–79%)
Patent ductus arteriosus	Often (30–79%)
Patent foramen ovale	Often (30–79%)
Secundum atrial septal defect	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Double uterus	Always
Frequent urinary tract infections	Always
Streak gonad	Always
Underdeveloped inner lips	Always
Enlarged kidney	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	Always
Gastrostomy tube feeding in infancy	Always
Acid reflux	Often (30–79%)
Anteriorly placed anus	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Often (30–79%)
Low-set ears	Often (30–79%)
Sensorineural hearing impairment	Often (30–79%)

Abnormality of the endocrine system

Trait	How often it is seen
Elevated circulating follicle stimulating hormone level	Often (30–79%)
Elevated circulating luteinizing hormone level	Often (30–79%)

Abnormality of the immune system

Trait	How often it is seen
Recurrent infections	Always

Abnormality of the respiratory system

Trait	How often it is seen
Floppy windpipe	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Short stature	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Increased plasma triglycerides	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 RBSN and how often each is seen. Find out more at hpo.jax.org.

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