Traits

Traits linked to MED12

mediator complex subunit 12

The Human Phenotype Ontology links 261 traits to MED12, by body system: features seen in people with one of the gene's rare conditions.

MED12

Abnormality of head or neck

Trait	How often it is seen
Bulbous nose	Always
Depressed nasal bridge	Always
Eye folds	Always
High palate	Always
Little lower jaw	Always
Long face	Always
Narrow face	Always
Narrow mouth	Always
Narrow opening between the eyelids	Always
Short philtrum	Always
Sparse eyebrow	Always
Triangular face	Always
Wide nasal bridge	Always
Big calvaria	Very often (80–99%)
Cleft of the mouth	Very often (80–99%)
Dental crowding	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
High forehead	Very often (80–99%)
Pit in front of the ear	Very often (80–99%)
Prominent forehead	Very often (80–99%)
Skin tag in front of the ear	Very often (80–99%)
Asymmetry of the posterior head	Often (30–79%)
Both sided cleft lip	Often (30–79%)
Broad neck	Often (30–79%)
Coarse facial features	Often (30–79%)
Decreased size of maxilla	Often (30–79%)
Decreased size of tooth	Often (30–79%)
Drooling	Often (30–79%)
Full lips	Often (30–79%)
Fused teeth	Often (30–79%)
Long philtrum	Often (30–79%)
Narrow nose	Often (30–79%)
Open mouth	Often (30–79%)
Prominent back of the head	Often (30–79%)
Prominent nasal bridge	Often (30–79%)
Prominent nose	Often (30–79%)
Relatively large head	Often (30–79%)
Right and left cleft palate	Often (30–79%)
Thick nasal alae	Often (30–79%)
Wide mouth	Often (30–79%)
Widely patent fontanelles and sutures	Often (30–79%)
Zygomatic flattening	Often (30–79%)
Abnormal dentition	Sometimes (5–29%)
Blockage of the rear opening of the nasal cavity	Sometimes (5–29%)
Broad head shape	Sometimes (5–29%)
Cleft soft palate	Sometimes (5–29%)
Deformity of the skull	Sometimes (5–29%)
High frontal hairline	Sometimes (5–29%)
Narrowing of the tear duct	Sometimes (5–29%)
One sided cleft palate	Sometimes (5–29%)
One sided cleft upper lip	Sometimes (5–29%)
Short chin	Sometimes (5–29%)
Thin red part of the upper lip	Sometimes (5–29%)
Widely spaced teeth	Sometimes (5–29%)
Cleft palate	Not recorded
Cleft upper lip	Not recorded
Decreased volume of lip	Not recorded
Deep philtrum	Not recorded
Delayed closure of the soft spot on the skull	Not recorded
Frontal bossing	Not recorded
Full lower lip	Not recorded
Long nose	Not recorded
Narrow nasal bridge	Not recorded
Narrow palate	Not recorded
Postnatal macrocephaly	Not recorded
Short neck	Not recorded
Smooth philtrum	Not recorded
Wider-than-typical soft spot of skull	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Decreased liver function	Always
Intestinal malrotation	Always
Intrahepatic bile duct dilatation	Always
Jaundice	Always
Absent anus	Very often (80–99%)
Feeding difficulties	Very often (80–99%)
Abdominal pain	Often (30–79%)
Abnormal gallbladder structure	Often (30–79%)
Abnormality of the biliary system	Often (30–79%)
Abnormality of the large intestine	Often (30–79%)
Constipation	Often (30–79%)
Cyst of the ductus choledochus	Often (30–79%)
Inguinal hernia	Often (30–79%)
Malrotation of colon	Often (30–79%)
Prolonged yellowing of skin in newborn	Often (30–79%)
Pyloric stenosis	Often (30–79%)
Slowed or blocked flow of bile from liver	Often (30–79%)
Acid reflux	Sometimes (5–29%)
Bile duct inflammation	Sometimes (5–29%)
Bile duct proliferation	Sometimes (5–29%)
Bladder exstrophy	Sometimes (5–29%)
Celiac disease	Sometimes (5–29%)
Enlarged liver	Sometimes (5–29%)
Enlarged vein in esophagus	Sometimes (5–29%)
Gastric varix	Sometimes (5–29%)
Hepatic fibrosis	Sometimes (5–29%)
Intrahepatic bile duct cysts	Sometimes (5–29%)
Liver failure	Sometimes (5–29%)
Meckel diverticulum	Sometimes (5–29%)
Portal inflammation	Sometimes (5–29%)
Scar tissue replaces healthy tissue in the liver	Sometimes (5–29%)
Stomach hernia	Sometimes (5–29%)
Umbilical hernia	Sometimes (5–29%)
Vomiting	Sometimes (5–29%)
Anteriorly placed anus	Not recorded
Narrowing of anal opening	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Delayed speech and language development	Always
Intellectual disability	Always
Abnormal speech pattern	Very often (80–99%)
Behavioral abnormality	Very often (80–99%)
Abnormality of the cerebellum	Often (30–79%)
Absent speech development	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Aplasia/Hypoplasia of the corpus callosum	Often (30–79%)
Attention deficit	Often (30–79%)
Epilepsy	Often (30–79%)
Global developmental delay	Often (30–79%)
IQ between 34 and 49	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Wide based walk	Often (30–79%)
Abnormal social behavior	Sometimes (5–29%)
Autism	Sometimes (5–29%)
Hallucinations	Sometimes (5–29%)
Irritability	Sometimes (5–29%)
Obsessive compulsive behavior	Sometimes (5–29%)
Psychosis	Sometimes (5–29%)
Schizophrenia	Sometimes (5–29%)
Too much cerebrospinal fluid in the brain	Sometimes (5–29%)
Aggressive behavior	Not recorded
Can't control feelings	Not recorded
Gray matter heterotopia	Not recorded
High pitched voice	Not recorded
Low frustration tolerance	Not recorded
More active than typical	Not recorded
Motor delay	Not recorded
Partial agenesis of the corpus callosum	Not recorded
Poor social interactions	Not recorded

Abnormality of limbs

Trait	How often it is seen
Broad big toe	Always
Broad thumb	Always
Broad toe	Often (30–79%)
Curvature of digit	Often (30–79%)
Dropped arches	Often (30–79%)
Finger joint hyperextensibility	Often (30–79%)
Limited elbow extension and supination	Often (30–79%)
Long slender fingers	Often (30–79%)
Abnormality of the thumb	Sometimes (5–29%)
Curvature of index finger	Sometimes (5–29%)
Finger syndactyly	Sometimes (5–29%)
Long thumb	Sometimes (5–29%)
Overlapping toe	Sometimes (5–29%)
Permanent flexion of the finger	Sometimes (5–29%)
Short fingers or toes	Sometimes (5–29%)
Short thumb	Sometimes (5–29%)
Single transverse palmar crease	Sometimes (5–29%)
Ulnar deviation of the hand	Sometimes (5–29%)
Joint contracture of the hand	Not recorded
Prominent fingertip pads	Not recorded
Radial deviation of finger	Not recorded
Split hand	Not recorded
Webbed fingers or toes	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Double-Jointed	Always
Low muscle tone	Very often (80–99%)
Scoliosis	Very often (80–99%)
Abnormality of the sternum	Often (30–79%)
Decreased muscle tone in infant	Often (30–79%)
Funnel chest	Often (30–79%)
Generalized low muscle tone in neonate	Often (30–79%)
Hypermobility of all joints	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Abnormal formation of the hip	Sometimes (5–29%)
Congenital diaphragmatic hernia	Sometimes (5–29%)
Narrow chest	Sometimes (5–29%)
Osteoporosis	Sometimes (5–29%)
Progressive flexion contractures	Sometimes (5–29%)
Thoracolumbar scoliosis	Sometimes (5–29%)
Excessive inward curvature of lower spine	Not recorded
Flexed joint that cannot be straightened	Not recorded
Generalized decreased muscle tone	Not recorded
Low muscle tone, in neonatal onset	Not recorded
Multiple joint contractures	Not recorded
Permanent flexion of the finger or toe	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
An opening in the wall separating the top two chambers of the heart	Often (30–79%)
Disease of the heart muscle	Often (30–79%)
Narrowing of aorta	Often (30–79%)
Patent ductus arteriosus	Often (30–79%)
Bulge in wall of large artery that carries blood away from heart	Sometimes (5–29%)
Enlarged liver and spleen	Sometimes (5–29%)
High blood pressure	Sometimes (5–29%)
Hole in heart wall separating two lower heart chambers	Sometimes (5–29%)
Hypersplenism	Sometimes (5–29%)
Increased blood pressure in blood vessels of lungs	Sometimes (5–29%)
Increased spleen size	Sometimes (5–29%)
Mitral valve prolapse	Sometimes (5–29%)
Narrowing of lung artery	Sometimes (5–29%)
Partial anomalous pulmonary venous return	Sometimes (5–29%)
Patent foramen ovale	Sometimes (5–29%)
Portal hypertension	Sometimes (5–29%)
Abnormality of the heart	Not recorded
Bulging of wall of large artery located above heart	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Frequent urinary tract infections	Always
Hydronephrosis	Always
Hypospadias	Often (30–79%)
Large testis	Often (30–79%)
Short penis	Often (30–79%)
Undescended testes	Often (30–79%)
Vesicoureteral reflux	Often (30–79%)
Abnormally closed or absent vagina	Sometimes (5–29%)
Ectopic ureteral orifice	Sometimes (5–29%)
Hydroureter	Sometimes (5–29%)
Pyelonephritis	Sometimes (5–29%)
Renal failure	Sometimes (5–29%)
Scrotum surrounds penis	Sometimes (5–29%)
Underdeveloped bladder	Sometimes (5–29%)
Smaller than typical growth of scrotum	Not recorded

Abnormality of the ear

Trait	How often it is seen
Microtia, first degree	Always
Simple ear	Always
Narrow ear canal	Very often (80–99%)
Abnormally shaped ears	Often (30–79%)
Cupped ear	Often (30–79%)
Ears rotated toward back of head	Often (30–79%)
Hearing impairment	Often (30–79%)
Low-set ears	Often (30–79%)
Mild hearing impairment	Often (30–79%)
Small ears	Often (30–79%)
Dizziness	Sometimes (5–29%)
Prominent ear	Sometimes (5–29%)
Sensorineural hearing impairment	Sometimes (5–29%)
Abnormally folded helix	Not recorded

Abnormality of the eye

Trait	How often it is seen
Drooping upper eyelid	Always
Pigmentary retinopathy	Always
Abnormally small eyeball	Often (30–79%)
Cross-eyed	Often (30–79%)
Farsightedness	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Optic nerve hypoplasia	Often (30–79%)
Wide-set eyes	Often (30–79%)
Convergence excess esotropia	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Frontal upsweep of hair	Always
Itching	Often (30–79%)
Facial wrinkling	Sometimes (5–29%)
Spinal dimple	Sometimes (5–29%)
Birthmark	Not recorded
Fine hair	Not recorded
Skin tags	Not recorded
Sparse hair	Not recorded

Growth abnormality

Trait	How often it is seen
Disproportionate tall stature	Very often (80–99%)
Faltering weight	Often (30–79%)
Short stature	Often (30–79%)
Slender build	Often (30–79%)
Tall stature	Often (30–79%)
Decreased body weight	Sometimes (5–29%)
Growth delay	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Small pituitary gland	Often (30–79%)
Decreased circulating insulin-like growth factor 1 concentration	Sometimes (5–29%)
Impaired growth-hormone response to glucagon stimulation test	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low platelet count	Sometimes (5–29%)
Vomiting blood	Sometimes (5–29%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Premature birth	Often (30–79%)
Premature rupture of membranes	Sometimes (5–29%)

Abnormality of the voice

Trait	How often it is seen
Abnormality of the voice	Very often (80–99%)
Nasal speech	Very often (80–99%)

Laboratory abnormality

Trait	How often it is seen
High blood bilirubin levels	Sometimes (5–29%)
High liver enzymes	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 MED12 and how often each is seen. Find out more at hpo.jax.org.

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