Traits

Traits linked to THOC2

THO complex subunit 2

The Human Phenotype Ontology links 77 traits to THOC2, 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
Delayed speech and language development	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Abnormal cerebral white matter morphology	Often (30–79%)
Abnormal gait	Often (30–79%)
Behavioral abnormality	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
IQ between 34 and 49	Often (30–79%)
Tremor	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Abnormality of neuronal migration	Sometimes (5–29%)
Abnormality of the cerebellum	Sometimes (5–29%)
Anxiety	Sometimes (5–29%)
Autism spectrum disorder	Sometimes (5–29%)
Cerebellar dysplasia	Sometimes (5–29%)
Cerebellar vermis hypoplasia	Sometimes (5–29%)
Depression	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Gliosis	Sometimes (5–29%)
Grand mal seizures	Sometimes (5–29%)
Hyperactive movements	Sometimes (5–29%)
Intellectual disability, severe	Sometimes (5–29%)
Repetitive movements	Sometimes (5–29%)
Self-mutilation	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Big calvaria	Always
Depressed nasal bridge	Always
Little lower jaw	Always
Nasal tip, upturned	Always
Short columella	Always
Abnormally small head	Often (30–79%)
High palate	Often (30–79%)
Broad forehead	Sometimes (5–29%)
Enlargement of skull bones	Sometimes (5–29%)
High forehead	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Club feet	Always
Fixed elbow flexion	Always
Hand clenching	Always
Hip flexion contracture	Always
Knee extension contracture	Always
Rocker bottom foot	Always
Partial hip dislocation	Sometimes (5–29%)
Single transverse palmar crease	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Arthrogryposis multiplex congenita	Always
Increased variability in muscle fiber diameter	Always
Low muscle tone	Often (30–79%)
Abnormal formation of the hip	Sometimes (5–29%)
Double-Jointed	Sometimes (5–29%)
Involuntary muscle stiffness, contraction, or spasm	Sometimes (5–29%)
Uncontrollable movement in upper arms	Sometimes (5–29%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Fetal hydrothorax	Always
High levels of amniotic fluid	Always
Less than 10 fetal movements in 12 hours	Always
Short fetal thigh bone length	Always
Fetal ascites	Often (30–79%)
Premature birth	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Cross-eyed	Sometimes (5–29%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Outward facing eye ball	Sometimes (5–29%)
Visual impairment	Sometimes (5–29%)
Wide-set eyes	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Overweight	Often (30–79%)
Short stature	Often (30–79%)
Small for gestational age	Sometimes (5–29%)
Truncal obesity	Sometimes (5–29%)
Increased body mass index	Rarely (1–4%)

Abnormality of the genitourinary system

Trait	How often it is seen
Microphallus	Often (30–79%)
Decreased testicular size	Sometimes (5–29%)
Short penis	Sometimes (5–29%)
Undescended testes	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Large ears	Sometimes (5–29%)
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Poorly developed lungs	Always
Pulmonary scarring	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Fetal skin edema	Always
Nonimmune hydrops fetalis	Always

Abnormality of the cardiovascular system

Trait	How often it is seen
Heart attack	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased response to growth hormone stimulation test	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 THOC2 and how often each is seen. Find out more at hpo.jax.org.

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