Traits

Traits linked to SOS2

SOS Ras/Rho guanine nucleotide exchange factor 2

The Human Phenotype Ontology links 80 traits to SOS2, 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
Short neck	Always
Webbed neck	Always
Cystic hygroma	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
Full lower lip	Very often (80–99%)
High forehead	Very often (80–99%)
High palate	Very often (80–99%)
Little lower jaw	Very often (80–99%)
Midface retrusion	Very often (80–99%)
Sparse eyebrow	Very often (80–99%)
Thickened skin folds of neck	Very often (80–99%)
Triangular face	Very often (80–99%)
Low hairline at back of neck	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal cardiovascular system morphology	Very often (80–99%)
Abnormal EKG	Very often (80–99%)
Narrowing of lung artery	Very often (80–99%)
Abnormal heart rate	Often (30–79%)
Abnormal pulmonary valve morphology	Often (30–79%)
Abnormality of the lymphatic system	Often (30–79%)
Abnormality of the spleen	Often (30–79%)
An opening in the wall separating the top two chambers of the heart	Sometimes (5–29%)
Enlarged and thickened heart muscle	Sometimes (5–29%)
Hole in heart wall separating two lower heart chambers	Sometimes (5–29%)
Narrowing of aorta	Sometimes (5–29%)
Narrowing of pulmonic valve	Sometimes (5–29%)
Patent ductus arteriosus	Rarely (1–4%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Double-Jointed	Very often (80–99%)
Funnel chest	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Pigeon chest	Very often (80–99%)
Wide rib cage	Very often (80–99%)
Delayed bone maturation	Often (30–79%)
Low muscle tone	Often (30–79%)
Scoliosis	Often (30–79%)
Osteopenia	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Bulging eye	Very often (80–99%)
Drooping upper eyelid	Very often (80–99%)
Wide-set eyes	Very often (80–99%)
Blue eyes	Often (30–79%)
Cross-eyed	Often (30–79%)
Prominent corneal nerve fibers	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Prolonged prothrombin time	Always
Abnormal platelet function	Often (30–79%)
Abnormality of coagulation	Often (30–79%)
Bleeding tendency	Often (30–79%)
Bruising susceptibility	Sometimes (5–29%)
Juvenile myelomonocytic leukemia	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Curly hair	Very often (80–99%)
Abnormal fingerprints	Often (30–79%)
Abnormal hair quantity	Often (30–79%)
Chicken skin	Often (30–79%)
Coarse hair	Often (30–79%)
Beauty mark	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Abnormal speech pattern	Very often (80–99%)
Difficulty articulating speech	Very often (80–99%)
Global developmental delay	Often (30–79%)
Neurodevelopmental delay	Often (30–79%)
Intellectual disability	Sometimes (5–29%)
Specific learning disability	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Very often (80–99%)
Thickened helices	Very often (80–99%)
Aplasia of the semicircular canal	Sometimes (5–29%)
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Undescended testes	Always
Abnormality of the reproductive system	Often (30–79%)
Dilatation of the renal pelvis	Sometimes (5–29%)
Hydroureter	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Curvature of little finger	Sometimes (5–29%)
Fused forearm bones	Sometimes (5–29%)
Short fingers or toes	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Absent/small abdominal wall muscles	Very often (80–99%)
Enlarged liver	Often (30–79%)
Feeding difficulties in infancy	Often (30–79%)

Abnormality of the endocrine system

Trait	How often it is seen
Hypogonadotropic hypogonadism	Very often (80–99%)
Delayed start of first period	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Short stature	Very often (80–99%)
Growth delay as children	Sometimes (5–29%)

Abnormality of the breast

Trait	How often it is seen
Wide-spaced nipples	Very often (80–99%)

Laboratory abnormality

Trait	How often it is seen
Swelling caused by excess lymph fluid under skin	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 SOS2 and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test